From 605ae53cf6a39c4fd641260673ed7f91d3548db2 Mon Sep 17 00:00:00 2001
From: Dan Mordechay <dan.mordechay@weka.io>
Date: Tue, 20 Oct 2026 14:43:15 +0300
Subject: [PATCH 1/3] setup: recommended linter configs for Go, Python and
 TypeScript

Add three core templates under setup/, rendered into every plugin:
golangci.yaml, ruff.toml and eslint.config.ldd.mjs. Each enables the
linter rules that the routing tables route to a design rule, at the
limits the rules name, and takes the file-length limit from
{{.FileMaxLines}}. Each says how to adopt it on an existing codebase:
golangci-lint's new-from-merge-base, ESLint's bulk suppressions, ruff on
changed files. The plugin never writes them into a repository.

- The gap linter's threshold line names the rule and the setup file that
  would hold a file-length limit. For Python it says that ruff has no
  file-length rule and the gap linter holds it; it no longer proposes
  adding pylint, a tool the repository may not use.
- The ldd-lint matrix checks that the named setup file sets the rule at
  the scalar's value. When golangci-lint, ruff or node is on PATH, it
  also runs each tool's own check of its file.
- Fix: ldd-lint.sh did not parse under bash 3.2 (macOS /bin/bash). bash
  3.2 misreads a case pattern inside a process substitution; the case
  moves into a function, dir_of.
- The READMEs and docs/quick-start.md say "zero configuration to run" and
  name the recommended setup.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 core/README.md                                |  17 +-
 core/includes/scripts/ldd-lint-langs.sh       |  37 +++-
 core/scripts/ldd-lint.sh                      |  17 +-
 core/scripts/ldd-lint_test.sh                 |  25 ++-
 core/setup/eslint.config.ldd.mjs              |  93 +++++++++
 core/setup/golangci.yaml                      |  82 ++++++++
 core/setup/ruff.toml                          |  53 +++++
 docs/quick-start.md                           |   7 +-
 go-linter-driven-development/CHANGELOG.md     |  13 ++
 go-linter-driven-development/README.md        |   4 +-
 .../scripts/ldd-detect_test.sh                |   5 +
 .../scripts/ldd-lint.sh                       |  54 +++--
 .../scripts/ldd-lint_test.sh                  | 187 ++++++++++++++++-
 .../scripts/ldd-scope_test.sh                 |   5 +
 .../setup/eslint.config.ldd.mjs               |  93 +++++++++
 .../setup/golangci.yaml                       |  82 ++++++++
 go-linter-driven-development/setup/ruff.toml  |  53 +++++
 lang/generic/passthrough/CHANGELOG.md         |  13 ++
 lang/generic/passthrough/README.md            |   5 +
 lang/generic/scripts/ldd-fixture.sh           |   7 +
 lang/go/passthrough/CHANGELOG.md              |  13 ++
 lang/go/passthrough/README.md                 |   4 +-
 lang/go/scripts/ldd-fixture.sh                |   5 +
 lang/python/passthrough/CHANGELOG.md          |  13 ++
 lang/python/passthrough/README.md             |  12 +-
 lang/python/scripts/ldd-fixture.sh            |   5 +
 lang/ts-react/passthrough/CHANGELOG.md        |  13 ++
 lang/ts-react/passthrough/README.md           |   5 +
 lang/ts-react/scripts/ldd-fixture.sh          |   5 +
 linter-driven-development/CHANGELOG.md        |  13 ++
 linter-driven-development/README.md           |   5 +
 .../scripts/ldd-detect_test.sh                |   7 +
 linter-driven-development/scripts/ldd-lint.sh |  54 +++--
 .../scripts/ldd-lint_test.sh                  | 189 +++++++++++++++++-
 .../scripts/ldd-scope_test.sh                 |   7 +
 .../setup/eslint.config.ldd.mjs               |  93 +++++++++
 linter-driven-development/setup/golangci.yaml |  82 ++++++++
 linter-driven-development/setup/ruff.toml     |  53 +++++
 python-linter-driven-development/CHANGELOG.md |  13 ++
 python-linter-driven-development/README.md    |  12 +-
 .../scripts/ldd-detect_test.sh                |   5 +
 .../scripts/ldd-lint.sh                       |  54 +++--
 .../scripts/ldd-lint_test.sh                  | 187 ++++++++++++++++-
 .../scripts/ldd-scope_test.sh                 |   5 +
 .../setup/eslint.config.ldd.mjs               |  93 +++++++++
 .../setup/golangci.yaml                       |  82 ++++++++
 .../setup/ruff.toml                           |  53 +++++
 .../CHANGELOG.md                              |  13 ++
 ts-react-linter-driven-development/README.md  |   5 +
 .../scripts/ldd-detect_test.sh                |   5 +
 .../scripts/ldd-lint.sh                       |  54 +++--
 .../scripts/ldd-lint_test.sh                  | 187 ++++++++++++++++-
 .../scripts/ldd-scope_test.sh                 |   5 +
 .../setup/eslint.config.ldd.mjs               |  93 +++++++++
 .../setup/golangci.yaml                       |  82 ++++++++
 .../setup/ruff.toml                           |  53 +++++
 56 files changed, 2353 insertions(+), 78 deletions(-)
 create mode 100644 core/setup/eslint.config.ldd.mjs
 create mode 100644 core/setup/golangci.yaml
 create mode 100644 core/setup/ruff.toml
 create mode 100644 go-linter-driven-development/setup/eslint.config.ldd.mjs
 create mode 100644 go-linter-driven-development/setup/golangci.yaml
 create mode 100644 go-linter-driven-development/setup/ruff.toml
 create mode 100644 linter-driven-development/setup/eslint.config.ldd.mjs
 create mode 100644 linter-driven-development/setup/golangci.yaml
 create mode 100644 linter-driven-development/setup/ruff.toml
 create mode 100644 python-linter-driven-development/setup/eslint.config.ldd.mjs
 create mode 100644 python-linter-driven-development/setup/golangci.yaml
 create mode 100644 python-linter-driven-development/setup/ruff.toml
 create mode 100644 ts-react-linter-driven-development/setup/eslint.config.ldd.mjs
 create mode 100644 ts-react-linter-driven-development/setup/golangci.yaml
 create mode 100644 ts-react-linter-driven-development/setup/ruff.toml

diff --git a/core/README.md b/core/README.md
index 07f0e7a..49136ae 100644
--- a/core/README.md
+++ b/core/README.md
@@ -190,6 +190,16 @@ differently from the other bindings:
   matrix reads the binding's `scripts/ldd-fixture.sh` for the source suffix, the
   comment forms, a test file's name and two linter configs per row: one that names the
   file-length rule and one that names a rule of a similar name.
+- `setup/golangci.yaml`, `setup/ruff.toml` and `setup/eslint.config.ldd.mjs`, the
+  recommended linter configurations, are core templates rendered into every plugin,
+  so the generic plugin carries all three for the languages it reviews. Each enables
+  the linter rules the bindings' routing tables route to a design rule, at the
+  limits the rules name, and takes the file-length limit from `{{.FileMaxLines}}`.
+  Each names its linter on purpose and carries a `residue-exempt:` marker. The gap
+  linter's threshold line names the file and rule that would hold a limit, and the
+  `ldd-lint` matrix checks that the file sets that rule at the scalar's value; when
+  `golangci-lint`, `ruff` or `node` is on PATH, the matrix also has each tool check
+  its file.
 - `scripts/check-repo-brain_test.sh` is a core template whose cases read one include,
   `scripts/repo-brain-fixture.sh`: the fixture rows (marker, code file, second
   package, sub-project) for every language the rendered gate's adapter serves. The
@@ -220,11 +230,11 @@ Hard residue: none. No plugin-name or command-prefix literal, golangci
 reference, source-file glob, nolint directive, scalar word or retired Go idiom is
 left in core/.
 
-Soft residue by token (130 lines):
+Soft residue by token (131 lines):
 
 | Token | Lines | Files |
 |---|---:|---:|
-| interface | 85 | 24 |
+| interface | 86 | 25 |
 | Go (the word) | 13 | 8 |
 | Go code fence | 12 | 1 |
 | Go stdlib | 9 | 5 |
@@ -234,7 +244,7 @@ Soft residue by token (130 lines):
 | race detector | 2 | 2 |
 | sync. | 1 | 1 |
 
-Soft residue by file (130 lines):
+Soft residue by file (131 lines):
 
 | File | Lines | Tokens |
 |---|---:|---:|
@@ -273,5 +283,6 @@ Soft residue by file (130 lines):
 | `rules/R2-self-validating-types.md` | 1 | 1 |
 | `rules/R7-test-placement.md` | 1 | 1 |
 | `scripts/ldd-scope_test.sh` | 1 | 1 |
+| `setup/golangci.yaml` | 1 | 1 |
 | `skills/linter-driven-development/SKILL.md` | 1 | 1 |
 <!-- residue:end -->
diff --git a/core/includes/scripts/ldd-lint-langs.sh b/core/includes/scripts/ldd-lint-langs.sh
index 4a7509b..54c3325 100644
--- a/core/includes/scripts/ldd-lint-langs.sh
+++ b/core/includes/scripts/ldd-lint-langs.sh
@@ -21,9 +21,15 @@
 #                                   nothing. A named rule belongs to the linter:
 #                                   its limit, its counting and whether it is on
 #                                   are the repository's decision.
-#   lint_file_length_snippet <id> <max>  the linter setting that would hold the
-#                                   limit, or the .ldd-lint.yaml entry when no
-#                                   linter rule is known: text to propose
+#   lint_setup_files                one line per recommended config under the
+#                                   plugin's setup/: file TAB the tool that checks it
+#   lint_setup_check <file> <setup dir> <work dir>  run that tool's own check of
+#                                   the file; exit 0 when the tool accepts it
+#   lint_file_length_proposal <id>  what would hold the limit in the
+#                                   repository's linter: the rule, named after
+#                                   the plugin's recommended config under setup/
+#                                   that sets it, or the .ldd-lint.yaml entry when
+#                                   the language's linter has no such rule
 
 lint_comment_style() {
   case "$1" in
@@ -126,12 +132,27 @@ lint_file_length_rule() {
   return 0
 }
 
-lint_file_length_snippet() {
+lint_setup_files() {
+  printf 'golangci.yaml\tgolangci-lint\n'
+  printf 'ruff.toml\truff\n'
+  printf 'eslint.config.ldd.mjs\tnode\n'
+}
+
+lint_setup_check() { # <file> <setup dir> <work dir>
+  case "$1" in
+    golangci.yaml)         golangci-lint config verify -c "$2/$1" ;;
+    ruff.toml)             printf 'x = 1\n' > "$3/ldd_setup_check.py" && (cd "$3" && ruff check --no-cache --config "$2/$1" ldd_setup_check.py) ;;
+    eslint.config.ldd.mjs) node --check "$2/$1" ;;
+    *)                     return 2 ;;
+  esac
+}
+
+lint_file_length_proposal() {
   case "$1" in
-    go)                    printf "revive in .golangci.yaml: - name: file-length-limit, arguments: [{max: %s, skip-comments: true, skip-blank-lines: true}]" "$2" ;;
-    typescript|javascript) printf "the eslint config: 'sonarjs/max-lines': ['error', { maximum: %s }]" "$2" ;;
-    python)                printf "pyproject.toml: [tool.pylint.format] max-module-lines = %s (pylint counts every line, comments and blank lines too)" "$2" ;;
-    *)                     printf "no linter rule is known for %s; a .ldd-lint.yaml entry file_max_lines: %s would state this limit" "$1" "$2" ;;
+    go)                    printf "a setting to propose, never to add on your own: revive file-length-limit, as the plugin's setup/golangci.yaml sets it" ;;
+    typescript|javascript) printf "a setting to propose, never to add on your own: sonarjs/max-lines, as the plugin's setup/eslint.config.ldd.mjs sets it" ;;
+    python)                printf "ruff has no file-length rule, so this script holds the limit; a .ldd-lint.yaml entry file_max_lines: <n> states another" ;;
+    *)                     printf "no linter rule is known for %s; a .ldd-lint.yaml entry file_max_lines: <n> states another limit" "$1" ;;
   esac
 }
 # ================== end linter table ==================
\ No newline at end of file
diff --git a/core/scripts/ldd-lint.sh b/core/scripts/ldd-lint.sh
index 90d76ae..5710d7f 100755
--- a/core/scripts/ldd-lint.sh
+++ b/core/scripts/ldd-lint.sh
@@ -162,6 +162,16 @@ trap 'rm -f "$SCOPE" "$INVENTORY"' EXIT
 list_candidates | by_language > "$SCOPE"
 if [[ -n "$FILES_LIST" ]]; then list_repo | by_language > "$INVENTORY"; else cp "$SCOPE" "$INVENTORY"; fi
 
+# dir_of <path> — the directory part of a relative path, "." for a file at
+# the root. A function, because bash 3.2 misreads a case pattern's ")" inside
+# a process substitution.
+dir_of() {
+  case "$1" in
+    */*) printf '%s\n' "${1%/*}" ;;
+    *)   printf '.\n' ;;
+  esac
+}
+
 # measured <path> — exit 0 when the file counts for this language: not under
 # an excluded directory, not a test, not generated. Every path the script
 # hands to find, head or awk starts with "./", and a directory is cut from a
@@ -193,7 +203,7 @@ run_file_length() { # <id> — every measured file of that language
     say "threshold: $id file length — set by $OVERRIDE_FILE ($max code lines)"
   else
     max="$DEFAULT_FILE_MAX_LINES"; src="profile default"
-    say "threshold: $id file length — profile default ($max code lines); the repository's linter does not hold it; a setting to propose, never to add on your own: $(lint_file_length_snippet "$id" "$max")"
+    say "threshold: $id file length — profile default ($max code lines); the repository's linter does not hold it; $(lint_file_length_proposal "$id")"
   fi
   while IFS=$'\t' read -r _ f; do
     measured "$f" || continue
@@ -217,7 +227,7 @@ run_package_size() { # <id> — every directory that holds a measured file of th
   awk -F'\t' -v id="$id" '$1 == id { print $2 }' "$INVENTORY" | while IFS= read -r f; do
     [[ -n "$skip" ]] && printf '%s\n' "$f" | grep -qE -- "$skip" && continue
     measured "$f" || continue
-    case "$f" in */*) printf '%s\n' "${f%/*}" ;; *) printf '.\n' ;; esac
+    dir_of "$f"
   done | LC_ALL=C sort | uniq -c | awk '{ n = $1; sub(/^[ \t]*[0-9]+[ \t]/, ""); print $0 "\t" n }' > "$counts"
   while IFS= read -r d; do
     n=$(awk -F'\t' -v d="$d" '$1 == d { print $2; exit }' "$counts")
@@ -228,8 +238,7 @@ run_package_size() { # <id> — every directory that holds a measured file of th
       finding "$d" "$n source files (warning at $warn, $src)"
     fi
   done < <(awk -F'\t' -v id="$id" '$1 == id { print $2 }' "$SCOPE" | while IFS= read -r f; do
-             measured "$f" || continue
-             case "$f" in */*) printf '%s\n' "${f%/*}" ;; *) printf '.\n' ;; esac
+             measured "$f" && dir_of "$f"
            done | LC_ALL=C sort -u)
   rm -f "$counts"
 }
diff --git a/core/scripts/ldd-lint_test.sh b/core/scripts/ldd-lint_test.sh
index 3b81d47..d0ee69b 100644
--- a/core/scripts/ldd-lint_test.sh
+++ b/core/scripts/ldd-lint_test.sh
@@ -87,6 +87,8 @@ fill_dir() {
 
 {{include "scripts/ldd-fixture.sh"}}
 
+{{include "scripts/ldd-lint-langs.sh"}}
+
 # ========================= cases =========================
 run_row_cases() { # runs every case against the current row
 
@@ -146,7 +148,16 @@ finish
 begin "the plugin's default names a linter setting to propose, never to add"
 write_src "src/a$FX_EXT" 1
 run_lint file-length
-expect_exit 0 && expect_has "profile default ($MAX_LINES code lines)" && expect_has "a setting to propose, never to add on your own: " && ok
+SETUP_DIR="$(dirname "$LINT")/../setup"
+if [[ -n "$FX_SETUP_FILE" ]]; then
+  expect_exit 0 && expect_has "profile default ($MAX_LINES code lines)" \
+    && expect_has "a setting to propose, never to add on your own: " \
+    && expect_has "$FX_LENGTH_RULE, as the plugin's setup/$FX_SETUP_FILE sets it" \
+    && { grep -q -- "$FX_LENGTH_RULE" "$SETUP_DIR/$FX_SETUP_FILE" && grep -q -- "$MAX_LINES" "$SETUP_DIR/$FX_SETUP_FILE" || bad "setup/$FX_SETUP_FILE does not set $FX_LENGTH_RULE at $MAX_LINES"; } \
+    && grep -q -- "$FX_LENGTH_RULE" "$SETUP_DIR/$FX_SETUP_FILE" && ok
+else
+  expect_exit 0 && expect_has "profile default ($MAX_LINES code lines)" && expect_has "a .ldd-lint.yaml entry file_max_lines" && ok
+fi
 finish
 
 begin "a file-length rule in the linter config hands file length to the linter"
@@ -316,6 +327,18 @@ for opt in --root --files --glob --test-re; do
   finish
 done
 
+# --- the recommended configs under setup/, checked by their own linters when
+# the machine has them ---
+SETUP_DIR="$(dirname "$LINT")/../setup"
+
+while IFS=$'\t' read -r setup_file setup_tool; do
+  begin "setup/$setup_file passes its own linter's check"
+  if ! command -v "$setup_tool" >/dev/null 2>&1; then skip "$setup_tool is not on PATH"; finish; continue; fi
+  OUT=$(lint_setup_check "$setup_file" "$SETUP_DIR" "$REPO" 2>&1); CODE=$?; ERR=""
+  expect_exit 0 && ok
+  finish
+done < <(lint_setup_files)
+
 # ========================= summary =========================
 echo
 echo "ldd-lint_test: $pass passed, $failed failed, $skipped skipped"
diff --git a/core/setup/eslint.config.ldd.mjs b/core/setup/eslint.config.ldd.mjs
new file mode 100644
index 0000000..f31218c
--- /dev/null
+++ b/core/setup/eslint.config.ldd.mjs
@@ -0,0 +1,93 @@
+// Recommended ESLint flat-config fragment of the linter-driven-development
+// plugins: every rule the plugin's routing table routes to one of the twelve
+// design rules, at the limits the rules name. Each rule line says which rule its
+// failures feed. The plugin never writes this file into a repository: the
+// repository's owners copy it, or the parts they want, beside eslint.config.js
+// and spread it into the exported array:
+//
+//   import ldd from './eslint.config.ldd.mjs'
+//   export default [...yourConfig, ...ldd]
+//
+// residue-exempt: an ESLint configuration names its plugins and rules on purpose.
+// It needs eslint-plugin-sonarjs, eslint-plugin-react, eslint-plugin-react-hooks,
+// eslint-plugin-promise, eslint-plugin-import and typescript-eslint; a repository
+// that does not use one of them leaves its rules out. Limits a repository already
+// sets stay the repository's: the linter is the authority for every threshold it
+// holds. Rules this file leaves out (style, imports, formatting) are the
+// repository's own choice.
+//
+// Adopt it on an existing codebase with ESLint's bulk suppressions: run
+// `npx eslint --suppress-all` once to record today's violations, so only new ones
+// fail; `npx eslint --prune-suppressions` drops the entries that are fixed.
+
+import importPlugin from 'eslint-plugin-import'
+import promise from 'eslint-plugin-promise'
+import react from 'eslint-plugin-react'
+import reactHooks from 'eslint-plugin-react-hooks'
+import sonarjs from 'eslint-plugin-sonarjs'
+import tseslint from 'typescript-eslint'
+
+export default [
+  {
+    files: ['**/*.{ts,tsx}'],
+    plugins: {
+      '@typescript-eslint': tseslint.plugin,
+      import: importPlugin,
+      promise,
+      react,
+      'react-hooks': reactHooks,
+      sonarjs,
+    },
+    rules: {
+      // R3 storifying
+      'sonarjs/cognitive-complexity': ['error', 15],
+      'sonarjs/cyclomatic-complexity': ['error', { threshold: 10 }],
+      'sonarjs/expression-complexity': ['error', { max: 5 }],
+      'sonarjs/max-lines-per-function': ['error', { maximum: 200 }],
+      'sonarjs/nested-control-flow': ['error', { maximumNestingLevel: 4 }],
+      'sonarjs/no-nested-conditional': 'error',
+      'sonarjs/no-nested-functions': 'error',
+      'sonarjs/elseif-without-else': 'error',
+      'react/no-unstable-nested-components': 'error',
+      // R1 primitive obsession
+      'max-params': ['error', 4],
+      'sonarjs/no-duplicate-string': ['error', { threshold: 3 }],
+      'sonarjs/max-union-size': ['error', { threshold: 4 }],
+      'sonarjs/no-identical-functions': 'error',
+      // R2 self-validating types: parse at the boundary
+      '@typescript-eslint/no-explicit-any': 'error',
+      '@typescript-eslint/no-non-null-assertion': 'error',
+      // R5 vertical slice: one juicy module per file; counts code lines only
+      'sonarjs/max-lines': ['error', { maximum: {{.FileMaxLines}} }],
+      'react/no-multi-comp': ['error', { ignoreStateless: false }],
+      // R8 no globals
+      'import/no-mutable-exports': 'error',
+      // R10 concurrency safety
+      'react-hooks/exhaustive-deps': 'error',
+      '@typescript-eslint/no-floating-promises': 'error',
+      '@typescript-eslint/no-misused-promises': 'error',
+      'promise/catch-or-return': 'error',
+      // R11 conditional dispatch
+      '@typescript-eslint/switch-exhaustiveness-check': 'error',
+      'sonarjs/no-nested-switch': 'error',
+      'sonarjs/max-switch-cases': 'error',
+      'sonarjs/no-small-switch': 'error',
+      // R12 mutation discipline
+      'no-param-reassign': ['error', { props: true }],
+      'sonarjs/prefer-read-only-props': 'error',
+      'react/no-direct-mutation-state': 'error',
+    },
+  },
+  {
+    // Tests are long and repeat literals by design.
+    files: ['**/*.test.{ts,tsx}', '**/*.spec.{ts,tsx}'],
+    rules: {
+      'sonarjs/max-lines-per-function': 'off',
+      'sonarjs/no-duplicate-string': 'off',
+      'sonarjs/no-nested-functions': 'off',
+      'max-params': 'off',
+      'react/no-multi-comp': 'off',
+      '@typescript-eslint/no-non-null-assertion': 'off',
+    },
+  },
+]
diff --git a/core/setup/golangci.yaml b/core/setup/golangci.yaml
new file mode 100644
index 0000000..6e32efb
--- /dev/null
+++ b/core/setup/golangci.yaml
@@ -0,0 +1,82 @@
+# Recommended golangci-lint v2 configuration of the linter-driven-development
+# plugins: every linter rule the plugin's routing table routes to one of the
+# twelve design rules, at the limits the rules name. Each linter line says which
+# rule its failures feed. The plugin never writes this file into a repository:
+# the repository's owners copy it, or the parts they want, into .golangci.yaml.
+# residue-exempt: a golangci-lint configuration names its linters on purpose.
+#
+# Limits a repository already sets stay the repository's: the linter is the
+# authority for every threshold it holds. Rules this file leaves out (style,
+# naming, formatting) are the repository's own choice.
+#
+# Adopt it on an existing codebase with the ratchet below: only issues in code
+# changed since the merge base with main fail, so old code is not a wall of
+# findings on day one. Remove the ratchet once the old findings are gone.
+
+version: "2"
+
+issues:
+  new-from-merge-base: main
+
+linters:
+  default: none
+  enable:
+    - gocyclo           # R3 storifying: cyclomatic complexity
+    - gocognit          # R3 storifying: cognitive complexity
+    - funlen            # R3 storifying: function length
+    - nestif            # R3 storifying: nesting depth
+    - maintidx          # R3 storifying, R1 types: maintainability index
+    - dupl              # R1 types: duplicated logic; a duplicated switch is R11
+    - exhaustive        # R11 conditional dispatch: missing enum cases
+    - gochecknoglobals  # R8 no globals
+    - gochecknoinits    # R8 no globals
+    - ireturn           # R6 test-only interfaces: a constructor that returns an interface
+    - govet             # R10 concurrency: copylocks
+    - revive            # R1 types, R5 vertical slice: the rules below
+    - errcheck          # mechanical: an error that is not handled
+    - wrapcheck         # mechanical: an error without the context of its layer
+    - goconst           # mechanical; an enum-shaped string is R1's "Name enum strings"
+  settings:
+    gocyclo:
+      min-complexity: 10
+    gocognit:
+      min-complexity: 15
+    funlen:
+      lines: 50
+      statements: 40
+    nestif:
+      min-complexity: 2
+    maintidx:
+      under: 20
+    dupl:
+      threshold: 100
+    exhaustive:
+      # A default branch does not count as handling a case: every new case is
+      # handled where the switch is.
+      default-signifies-exhaustive: false
+    govet:
+      enable:
+        - copylocks
+    goconst:
+      min-len: 3
+      min-occurrences: 3
+    revive:
+      rules:
+        - name: argument-limit          # R1: more than 4 parameters wants a parameter object
+          arguments: [4]
+        - name: function-result-limit   # R1: more than 3 results wants a named result type
+          arguments: [3]
+        - name: file-length-limit       # R5: one juicy type per file; counts code lines only
+          arguments: [{max: {{.FileMaxLines}}, skip-comments: true, skip-blank-lines: true}]
+        - name: early-return            # mechanical: invert the condition and return early
+  exclusions:
+    rules:
+      # Tests are long and repeat literals by design.
+      - path: _test\.go
+        linters:
+          - funlen
+          - gocognit
+          - gocyclo
+          - maintidx
+          - dupl
+          - goconst
diff --git a/core/setup/ruff.toml b/core/setup/ruff.toml
new file mode 100644
index 0000000..1ffb4c6
--- /dev/null
+++ b/core/setup/ruff.toml
@@ -0,0 +1,53 @@
+# Recommended ruff configuration of the linter-driven-development plugins:
+# every rule the plugin's routing table routes to one of the twelve design
+# rules, at the limits the rules name. Each rule says which rule its failures
+# feed. The plugin never writes this file into a repository: the repository's
+# owners copy it, or the parts they want, into ruff.toml, or into
+# pyproject.toml with each table name prefixed by "tool.ruff." ([lint] becomes
+# [tool.ruff.lint]).
+# residue-exempt: a ruff configuration names its rule codes on purpose.
+#
+# Limits a repository already sets stay the repository's: the linter is the
+# authority for every threshold it holds. Rules this file leaves out (style,
+# docstrings, imports) are the repository's own choice. ruff has no file-length
+# rule: the plugin's gap linter, scripts/ldd-lint.sh file-length, holds that
+# limit at {{.FileMaxLines}} code lines.
+#
+# Adopt it on an existing codebase one change at a time: run ruff on the files
+# changed since the merge base with main, so old code is not a wall of
+# findings on day one:
+#   git diff --name-only --diff-filter=d "$(git merge-base HEAD main)" -- '*.py' | xargs ruff check
+
+[lint]
+# PLR1702 (nested blocks) is a preview rule.
+preview = true
+explicit-preview-rules = true
+extend-select = [
+  "C901",     # R3 storifying: complexity
+  "PLR0911",  # R3 storifying: too many returns
+  "PLR0912",  # R3 storifying: too many branches
+  "PLR0915",  # R3 storifying: too many statements
+  "PLR1702",  # R3 storifying: nesting
+  "PLR0913",  # R1 types: too many arguments wants a parameter object
+  "PLR2004",  # R1 types: a magic value; an enum-shaped string is "Name enum strings"
+  "FBT001",   # R11 conditional dispatch: a boolean positional parameter
+  "FBT002",   # R11 conditional dispatch: a boolean default parameter
+  "PLW0603",  # R8 no globals: a global statement
+  "B006",     # R12 mutation discipline: a mutable default argument
+  "B008",     # R12 mutation discipline: a call in a default argument
+]
+
+[lint.mccabe]
+max-complexity = 8
+
+[lint.pylint]
+max-args = 4          # self and cls are not counted
+max-branches = 12
+max-returns = 6
+max-statements = 50
+max-nested-blocks = 5
+
+[lint.per-file-ignores]
+# Tests repeat literals and take many fixtures by design.
+"**/test_*.py" = ["PLR2004", "PLR0913", "FBT001", "FBT002"]
+"**/*_test.py" = ["PLR2004", "PLR0913", "FBT001", "FBT002"]
diff --git a/docs/quick-start.md b/docs/quick-start.md
index 3b60ecf..9d92c40 100644
--- a/docs/quick-start.md
+++ b/docs/quick-start.md
@@ -25,8 +25,11 @@ they share it.
 /plugin install go-linter-driven-development@ai-coding-rules
 ```
 
-No configuration. The plugin finds your test and lint commands in the Taskfile,
-Makefile, README or CLAUDE.md. The first time the workflow starts, Claude asks for
+No configuration to run. The plugin finds your test and lint commands in the
+Taskfile, Makefile, README or CLAUDE.md. The plugin's `setup/` directory holds a
+recommended linter configuration for Go, Python and TypeScript; copying it, or the
+parts you want, makes the design triggers fire. The plugin never writes it into
+your repository. The first time the workflow starts, Claude asks for
 permission to use the skill. Choose "Yes, and don't ask again for this directory".
 
 ## 1. A feature or a bug fix, from zero
diff --git a/go-linter-driven-development/CHANGELOG.md b/go-linter-driven-development/CHANGELOG.md
index 36bff47..ef2e41a 100644
--- a/go-linter-driven-development/CHANGELOG.md
+++ b/go-linter-driven-development/CHANGELOG.md
@@ -7,6 +7,15 @@ Format based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); versio
 
 ### Added
 
+- **A recommended linter setup.** `setup/golangci.yaml`, `setup/ruff.toml` and
+  `setup/eslint.config.ldd.mjs` enable every linter rule the routing table routes to
+  a design rule, at the limits the rules name, with a way to adopt each on an
+  existing codebase: golangci-lint's merge-base ratchet, ESLint's bulk
+  suppressions, and ruff on changed files. The plugin never writes them into a
+  repository. The gap linter's threshold line names the file and rule that would
+  hold a file-length limit; for Python, where ruff has no file-length rule, it says
+  that the gap linter holds it.
+
 - **A gap linter for the design triggers no linter holds.** `scripts/ldd-lint.sh`
   measures lines per source file (`file-length`) and source files per directory
   (`package-size`). Where the repository's linter config names a file-length rule,
@@ -33,6 +42,10 @@ Format based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); versio
 
 ### Fixed
 
+- **The gap linter runs under bash 3.2.** macOS's `/bin/bash` stopped
+  `ldd-lint.sh` with a syntax error: bash 3.2 misreads a `case` pattern inside a
+  process substitution. The script now runs under bash 3.2 and bash 5.
+
 - **A value-taking option given last no longer hangs the review scripts.** When
   `ldd-detect.sh` or `ldd-scope.sh` got an option such as `--root` or `--base` as
   its last argument, the script looped forever. It now stops with "<option> needs
diff --git a/go-linter-driven-development/README.md b/go-linter-driven-development/README.md
index 5c15ab5..b7f0d41 100644
--- a/go-linter-driven-development/README.md
+++ b/go-linter-driven-development/README.md
@@ -209,7 +209,9 @@ Should show: `go-linter-driven-development (enabled)`
 
 The scenario guide — the easiest start first, then code you already wrote, a plan you already have, and running the plugin from a subagent — is [docs/quick-start.md](https://github.com/buzzdan/ai-coding-rules/blob/main/docs/quick-start.md) in the main repository.
 
-**Zero configuration required.** The plugin discovers your project's test and lint commands from `README.md`, `CLAUDE.md`, `Makefile`, or `Taskfile.yaml`. Just install and go.
+**Zero configuration to run.** The plugin discovers your project's test and lint commands from `README.md`, `CLAUDE.md`, `Makefile`, or `Taskfile.yaml`. Just install and go.
+
+**The recommended setup makes the design triggers fire.** `setup/golangci.yaml` in the plugin directory enables every linter the routing table routes to a design rule, at the limits the rules name, with a ratchet so only new code fails at first. The plugin never writes it into your repository: copy it, or the parts you want, into `.golangci.yaml`. Limits your configuration already sets stay yours.
 
 ### The Easiest Way: Just Talk to It
 
diff --git a/go-linter-driven-development/scripts/ldd-detect_test.sh b/go-linter-driven-development/scripts/ldd-detect_test.sh
index a1822b0..24b78bb 100644
--- a/go-linter-driven-development/scripts/ldd-detect_test.sh
+++ b/go-linter-driven-development/scripts/ldd-detect_test.sh
@@ -141,6 +141,9 @@ questions_in_rules() {
 #   FX_BLOCK_OPEN      the line that opens a block comment, "" when the
 #   FX_BLOCK_CLOSE     language has none, and the line that closes it
 #   FX_SKIP_FILES      source file names a directory count leaves out
+#   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
+#                      the file-length limit, and FX_LENGTH_RULE its rule; both
+#                      "" when the language's linter has no file-length rule
 #   fx_test_file <dir> <n>             a test file's path in <dir>
 #   FX_LINTER_CONFIG   the path, under the repository root, of the file that
 #                      fx_write_linter_config writes, and FX_LINTER_COMMENT the
@@ -156,6 +159,8 @@ FX_NATIVE="go"
 
 use_row() {
   FX_LINTER_CONFIG='.golangci.yaml'
+  FX_SETUP_FILE='golangci.yaml'
+  FX_LENGTH_RULE='file-length-limit'
   FX_LINTER_COMMENT='#'
   FX_EXT='.go'
   FX_LINE_COMMENT='// note'
diff --git a/go-linter-driven-development/scripts/ldd-lint.sh b/go-linter-driven-development/scripts/ldd-lint.sh
index 3423749..9768869 100755
--- a/go-linter-driven-development/scripts/ldd-lint.sh
+++ b/go-linter-driven-development/scripts/ldd-lint.sh
@@ -222,9 +222,15 @@ lang_is_test() {
 #                                   nothing. A named rule belongs to the linter:
 #                                   its limit, its counting and whether it is on
 #                                   are the repository's decision.
-#   lint_file_length_snippet <id> <max>  the linter setting that would hold the
-#                                   limit, or the .ldd-lint.yaml entry when no
-#                                   linter rule is known: text to propose
+#   lint_setup_files                one line per recommended config under the
+#                                   plugin's setup/: file TAB the tool that checks it
+#   lint_setup_check <file> <setup dir> <work dir>  run that tool's own check of
+#                                   the file; exit 0 when the tool accepts it
+#   lint_file_length_proposal <id>  what would hold the limit in the
+#                                   repository's linter: the rule, named after
+#                                   the plugin's recommended config under setup/
+#                                   that sets it, or the .ldd-lint.yaml entry when
+#                                   the language's linter has no such rule
 
 lint_comment_style() {
   case "$1" in
@@ -327,12 +333,27 @@ lint_file_length_rule() {
   return 0
 }
 
-lint_file_length_snippet() {
+lint_setup_files() {
+  printf 'golangci.yaml\tgolangci-lint\n'
+  printf 'ruff.toml\truff\n'
+  printf 'eslint.config.ldd.mjs\tnode\n'
+}
+
+lint_setup_check() { # <file> <setup dir> <work dir>
+  case "$1" in
+    golangci.yaml)         golangci-lint config verify -c "$2/$1" ;;
+    ruff.toml)             printf 'x = 1\n' > "$3/ldd_setup_check.py" && (cd "$3" && ruff check --no-cache --config "$2/$1" ldd_setup_check.py) ;;
+    eslint.config.ldd.mjs) node --check "$2/$1" ;;
+    *)                     return 2 ;;
+  esac
+}
+
+lint_file_length_proposal() {
   case "$1" in
-    go)                    printf "revive in .golangci.yaml: - name: file-length-limit, arguments: [{max: %s, skip-comments: true, skip-blank-lines: true}]" "$2" ;;
-    typescript|javascript) printf "the eslint config: 'sonarjs/max-lines': ['error', { maximum: %s }]" "$2" ;;
-    python)                printf "pyproject.toml: [tool.pylint.format] max-module-lines = %s (pylint counts every line, comments and blank lines too)" "$2" ;;
-    *)                     printf "no linter rule is known for %s; a .ldd-lint.yaml entry file_max_lines: %s would state this limit" "$1" "$2" ;;
+    go)                    printf "a setting to propose, never to add on your own: revive file-length-limit, as the plugin's setup/golangci.yaml sets it" ;;
+    typescript|javascript) printf "a setting to propose, never to add on your own: sonarjs/max-lines, as the plugin's setup/eslint.config.ldd.mjs sets it" ;;
+    python)                printf "ruff has no file-length rule, so this script holds the limit; a .ldd-lint.yaml entry file_max_lines: <n> states another" ;;
+    *)                     printf "no linter rule is known for %s; a .ldd-lint.yaml entry file_max_lines: <n> states another limit" "$1" ;;
   esac
 }
 # ================== end linter table ==================
@@ -404,6 +425,16 @@ trap 'rm -f "$SCOPE" "$INVENTORY"' EXIT
 list_candidates | by_language > "$SCOPE"
 if [[ -n "$FILES_LIST" ]]; then list_repo | by_language > "$INVENTORY"; else cp "$SCOPE" "$INVENTORY"; fi
 
+# dir_of <path> — the directory part of a relative path, "." for a file at
+# the root. A function, because bash 3.2 misreads a case pattern's ")" inside
+# a process substitution.
+dir_of() {
+  case "$1" in
+    */*) printf '%s\n' "${1%/*}" ;;
+    *)   printf '.\n' ;;
+  esac
+}
+
 # measured <path> — exit 0 when the file counts for this language: not under
 # an excluded directory, not a test, not generated. Every path the script
 # hands to find, head or awk starts with "./", and a directory is cut from a
@@ -435,7 +466,7 @@ run_file_length() { # <id> — every measured file of that language
     say "threshold: $id file length — set by $OVERRIDE_FILE ($max code lines)"
   else
     max="$DEFAULT_FILE_MAX_LINES"; src="profile default"
-    say "threshold: $id file length — profile default ($max code lines); the repository's linter does not hold it; a setting to propose, never to add on your own: $(lint_file_length_snippet "$id" "$max")"
+    say "threshold: $id file length — profile default ($max code lines); the repository's linter does not hold it; $(lint_file_length_proposal "$id")"
   fi
   while IFS=$'\t' read -r _ f; do
     measured "$f" || continue
@@ -459,7 +490,7 @@ run_package_size() { # <id> — every directory that holds a measured file of th
   awk -F'\t' -v id="$id" '$1 == id { print $2 }' "$INVENTORY" | while IFS= read -r f; do
     [[ -n "$skip" ]] && printf '%s\n' "$f" | grep -qE -- "$skip" && continue
     measured "$f" || continue
-    case "$f" in */*) printf '%s\n' "${f%/*}" ;; *) printf '.\n' ;; esac
+    dir_of "$f"
   done | LC_ALL=C sort | uniq -c | awk '{ n = $1; sub(/^[ \t]*[0-9]+[ \t]/, ""); print $0 "\t" n }' > "$counts"
   while IFS= read -r d; do
     n=$(awk -F'\t' -v d="$d" '$1 == d { print $2; exit }' "$counts")
@@ -470,8 +501,7 @@ run_package_size() { # <id> — every directory that holds a measured file of th
       finding "$d" "$n source files (warning at $warn, $src)"
     fi
   done < <(awk -F'\t' -v id="$id" '$1 == id { print $2 }' "$SCOPE" | while IFS= read -r f; do
-             measured "$f" || continue
-             case "$f" in */*) printf '%s\n' "${f%/*}" ;; *) printf '.\n' ;; esac
+             measured "$f" && dir_of "$f"
            done | LC_ALL=C sort -u)
   rm -f "$counts"
 }
diff --git a/go-linter-driven-development/scripts/ldd-lint_test.sh b/go-linter-driven-development/scripts/ldd-lint_test.sh
index 7638faf..5192d27 100644
--- a/go-linter-driven-development/scripts/ldd-lint_test.sh
+++ b/go-linter-driven-development/scripts/ldd-lint_test.sh
@@ -105,6 +105,9 @@ fill_dir() {
 #   FX_BLOCK_OPEN      the line that opens a block comment, "" when the
 #   FX_BLOCK_CLOSE     language has none, and the line that closes it
 #   FX_SKIP_FILES      source file names a directory count leaves out
+#   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
+#                      the file-length limit, and FX_LENGTH_RULE its rule; both
+#                      "" when the language's linter has no file-length rule
 #   fx_test_file <dir> <n>             a test file's path in <dir>
 #   FX_LINTER_CONFIG   the path, under the repository root, of the file that
 #                      fx_write_linter_config writes, and FX_LINTER_COMMENT the
@@ -120,6 +123,8 @@ FX_NATIVE="go"
 
 use_row() {
   FX_LINTER_CONFIG='.golangci.yaml'
+  FX_SETUP_FILE='golangci.yaml'
+  FX_LENGTH_RULE='file-length-limit'
   FX_LINTER_COMMENT='#'
   FX_EXT='.go'
   FX_LINE_COMMENT='// note'
@@ -180,6 +185,165 @@ fx_write_linter_config_other() {
   printf 'version: "2"\nlinters:\n  settings:\n    revive:\n      rules:\n        - name: argument-limit\n          arguments: [4]\n' > "$REPO/.golangci.yaml"
 }
 
+# ==================== linter table ====================
+# What the gap linter needs to know per language id: how a comment is written,
+# which source files a directory count leaves out, and whether the
+# repository's own linter holds the file-length limit. The same table is
+# rendered into every plugin, so two plugins measure one file the same way.
+# residue-exempt: the table names every language's linter and config file on
+# purpose, the same in every rendering.
+#
+#   lint_comment_style <id>         c (// and /* */), d (also /+ +/) or hash (#)
+#   lint_strip_comments <style> <file>  the file with every comment removed and
+#                                   string literals kept, one output line per
+#                                   input line: a comment-only line prints empty.
+#                                   Styles: c, d, hash (# and triple-quoted
+#                                   strings), ini (# and a leading ;)
+#   lint_package_skip_re <id>       ERE over a relative path: source files a
+#                                   directory count leaves out (an index module,
+#                                   a package marker, generated stubs); "" for none
+#   lint_file_length_rule <id>      "<rule> in <config file>" when a linter config
+#                                   at the repository root names a file-length
+#                                   rule outside a comment, else
+#                                   nothing. A named rule belongs to the linter:
+#                                   its limit, its counting and whether it is on
+#                                   are the repository's decision.
+#   lint_setup_files                one line per recommended config under the
+#                                   plugin's setup/: file TAB the tool that checks it
+#   lint_setup_check <file> <setup dir> <work dir>  run that tool's own check of
+#                                   the file; exit 0 when the tool accepts it
+#   lint_file_length_proposal <id>  what would hold the limit in the
+#                                   repository's linter: the rule, named after
+#                                   the plugin's recommended config under setup/
+#                                   that sets it, or the .ldd-lint.yaml entry when
+#                                   the language's linter has no such rule
+
+lint_comment_style() {
+  case "$1" in
+    python|ruby|shell) printf 'hash' ;;
+    d)                 printf 'd' ;;
+    *)                 printf 'c' ;;
+  esac
+}
+
+lint_package_skip_re() {
+  case "$1" in
+    go)                    printf '%s' '(_gen|\.pb)\.go$' ;;
+    python)                printf '%s' '(^|/)(__init__|conftest)\.py$|_pb2(_grpc)?\.py$' ;;
+    typescript|javascript) printf '%s' '(^|/)index\.[cm]?[jt]sx?$|\.stories\.[cm]?[jt]sx?$' ;;
+  esac
+  return 0
+}
+
+# LINT_STRIP_AWK walks each line one character at a time. A quote opens a
+# string that a comment marker cannot end; single and double quotes close at
+# the end of the line, a backtick string (c and d) and a triple-quoted string
+# (hash) run on. A block comment may open after code and run on. The awk uses
+# substr and string compares only, so mawk, gawk and BSD awk read it alike.
+LINT_STRIP_AWK='
+BEGIN { bq = sprintf("%c", 96); sq = sprintf("%c", 39); dq = "\"" }
+{
+  line = $0; out = ""; n = length(line); i = 1
+  if (q == dq || q == sq) q = ""
+  while (i <= n) {
+    if (inblock) {
+      if (substr(line, i, length(closer)) == closer) { inblock = 0; i += length(closer); out = out " "; continue }
+      i++; continue
+    }
+    ch = substr(line, i, 1)
+    if (q != "") {
+      if (ch == "\\" && (q == dq || q == sq)) { out = out substr(line, i, 2); i += 2; continue }
+      if (substr(line, i, length(q)) == q) { out = out q; i += length(q); q = ""; continue }
+      out = out ch; i++; continue
+    }
+    if (style == "hash" || style == "ini") {
+      if (ch == "#") break
+      if (style == "ini" && ch == ";" && out ~ /^[ \t]*$/) break
+      three = substr(line, i, 3)
+      if (style == "hash" && (three == dq dq dq || three == sq sq sq)) { q = three; out = out three; i += 3; continue }
+    } else {
+      two = substr(line, i, 2)
+      if (two == "//") break
+      if (two == "/*" || (style == "d" && two == "/+")) { inblock = 1; closer = (two == "/+") ? "+/" : "*/"; out = out " "; i += 2; continue }
+      if (ch == bq) { q = bq; out = out ch; i++; continue }
+    }
+    if (ch == dq || ch == sq) { q = ch; out = out ch; i++; continue }
+    out = out ch; i++
+  }
+  print out
+}
+'
+
+lint_strip_comments() { # <style> <file>
+  awk -v style="$1" "$LINT_STRIP_AWK" "$2"
+}
+
+# _lint_config_style <config file> — how that config format writes a comment
+_lint_config_style() {
+  case "$1" in
+    *.yaml|*.yml|*.toml) printf 'hash' ;;
+    *.cfg|*.ini|.pylintrc|pylintrc) printf 'ini' ;;
+    *) printf 'c' ;;
+  esac
+}
+
+# _lint_names <ERE> <file>... — print the first file whose text outside its
+# comments matches the pattern
+_lint_names() {
+  local re="$1" f; shift
+  for f in "$@"; do
+    [[ -f "$f" ]] || continue
+    lint_strip_comments "$(_lint_config_style "$f")" "./$f" 2>/dev/null | grep -qE -- "$re" && { printf '%s' "$f"; return 0; }
+  done
+  return 1
+}
+
+lint_file_length_rule() {
+  local f
+  case "$1" in
+    go)
+      f=$(_lint_names 'file-length-limit' .golangci.yaml .golangci.yml .golangci.toml .golangci.json) \
+        && printf 'revive file-length-limit in %s' "$f" ;;
+    typescript|javascript)
+      local configs=(eslint.config.js eslint.config.mjs eslint.config.cjs eslint.config.ts eslint.config.mts eslint.config.cts
+                     .eslintrc .eslintrc.js .eslintrc.cjs .eslintrc.json .eslintrc.yml .eslintrc.yaml)
+      if f=$(_lint_names 'sonarjs/max-lines([^-a-zA-Z]|$)' "${configs[@]}"); then
+        printf 'sonarjs/max-lines in %s' "$f"
+      elif f=$(_lint_names '(^|[^-/a-zA-Z])max-lines([^-a-zA-Z]|$)' "${configs[@]}"); then
+        printf 'max-lines in %s' "$f"
+      fi ;;
+    python)
+      f=$(_lint_names '^[[:space:]]*max-module-lines[[:space:]]*=' pyproject.toml .pylintrc pylintrc setup.cfg tox.ini) \
+        && printf 'pylint max-module-lines in %s' "$f" ;;
+  esac
+  return 0
+}
+
+lint_setup_files() {
+  printf 'golangci.yaml\tgolangci-lint\n'
+  printf 'ruff.toml\truff\n'
+  printf 'eslint.config.ldd.mjs\tnode\n'
+}
+
+lint_setup_check() { # <file> <setup dir> <work dir>
+  case "$1" in
+    golangci.yaml)         golangci-lint config verify -c "$2/$1" ;;
+    ruff.toml)             printf 'x = 1\n' > "$3/ldd_setup_check.py" && (cd "$3" && ruff check --no-cache --config "$2/$1" ldd_setup_check.py) ;;
+    eslint.config.ldd.mjs) node --check "$2/$1" ;;
+    *)                     return 2 ;;
+  esac
+}
+
+lint_file_length_proposal() {
+  case "$1" in
+    go)                    printf "a setting to propose, never to add on your own: revive file-length-limit, as the plugin's setup/golangci.yaml sets it" ;;
+    typescript|javascript) printf "a setting to propose, never to add on your own: sonarjs/max-lines, as the plugin's setup/eslint.config.ldd.mjs sets it" ;;
+    python)                printf "ruff has no file-length rule, so this script holds the limit; a .ldd-lint.yaml entry file_max_lines: <n> states another" ;;
+    *)                     printf "no linter rule is known for %s; a .ldd-lint.yaml entry file_max_lines: <n> states another limit" "$1" ;;
+  esac
+}
+# ================== end linter table ==================
+
 # ========================= cases =========================
 run_row_cases() { # runs every case against the current row
 
@@ -239,7 +403,16 @@ finish
 begin "the plugin's default names a linter setting to propose, never to add"
 write_src "src/a$FX_EXT" 1
 run_lint file-length
-expect_exit 0 && expect_has "profile default ($MAX_LINES code lines)" && expect_has "a setting to propose, never to add on your own: " && ok
+SETUP_DIR="$(dirname "$LINT")/../setup"
+if [[ -n "$FX_SETUP_FILE" ]]; then
+  expect_exit 0 && expect_has "profile default ($MAX_LINES code lines)" \
+    && expect_has "a setting to propose, never to add on your own: " \
+    && expect_has "$FX_LENGTH_RULE, as the plugin's setup/$FX_SETUP_FILE sets it" \
+    && { grep -q -- "$FX_LENGTH_RULE" "$SETUP_DIR/$FX_SETUP_FILE" && grep -q -- "$MAX_LINES" "$SETUP_DIR/$FX_SETUP_FILE" || bad "setup/$FX_SETUP_FILE does not set $FX_LENGTH_RULE at $MAX_LINES"; } \
+    && grep -q -- "$FX_LENGTH_RULE" "$SETUP_DIR/$FX_SETUP_FILE" && ok
+else
+  expect_exit 0 && expect_has "profile default ($MAX_LINES code lines)" && expect_has "a .ldd-lint.yaml entry file_max_lines" && ok
+fi
 finish
 
 begin "a file-length rule in the linter config hands file length to the linter"
@@ -409,6 +582,18 @@ for opt in --root --files --glob --test-re; do
   finish
 done
 
+# --- the recommended configs under setup/, checked by their own linters when
+# the machine has them ---
+SETUP_DIR="$(dirname "$LINT")/../setup"
+
+while IFS=$'\t' read -r setup_file setup_tool; do
+  begin "setup/$setup_file passes its own linter's check"
+  if ! command -v "$setup_tool" >/dev/null 2>&1; then skip "$setup_tool is not on PATH"; finish; continue; fi
+  OUT=$(lint_setup_check "$setup_file" "$SETUP_DIR" "$REPO" 2>&1); CODE=$?; ERR=""
+  expect_exit 0 && ok
+  finish
+done < <(lint_setup_files)
+
 # ========================= summary =========================
 echo
 echo "ldd-lint_test: $pass passed, $failed failed, $skipped skipped"
diff --git a/go-linter-driven-development/scripts/ldd-scope_test.sh b/go-linter-driven-development/scripts/ldd-scope_test.sh
index 9d7af0c..954433b 100755
--- a/go-linter-driven-development/scripts/ldd-scope_test.sh
+++ b/go-linter-driven-development/scripts/ldd-scope_test.sh
@@ -117,6 +117,9 @@ mk_repo() { fx_write_marker "$REPO" fixture; fx_write_code; mk_docs; }
 #   FX_BLOCK_OPEN      the line that opens a block comment, "" when the
 #   FX_BLOCK_CLOSE     language has none, and the line that closes it
 #   FX_SKIP_FILES      source file names a directory count leaves out
+#   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
+#                      the file-length limit, and FX_LENGTH_RULE its rule; both
+#                      "" when the language's linter has no file-length rule
 #   fx_test_file <dir> <n>             a test file's path in <dir>
 #   FX_LINTER_CONFIG   the path, under the repository root, of the file that
 #                      fx_write_linter_config writes, and FX_LINTER_COMMENT the
@@ -132,6 +135,8 @@ FX_NATIVE="go"
 
 use_row() {
   FX_LINTER_CONFIG='.golangci.yaml'
+  FX_SETUP_FILE='golangci.yaml'
+  FX_LENGTH_RULE='file-length-limit'
   FX_LINTER_COMMENT='#'
   FX_EXT='.go'
   FX_LINE_COMMENT='// note'
diff --git a/go-linter-driven-development/setup/eslint.config.ldd.mjs b/go-linter-driven-development/setup/eslint.config.ldd.mjs
new file mode 100644
index 0000000..3e47c93
--- /dev/null
+++ b/go-linter-driven-development/setup/eslint.config.ldd.mjs
@@ -0,0 +1,93 @@
+// Recommended ESLint flat-config fragment of the linter-driven-development
+// plugins: every rule the plugin's routing table routes to one of the twelve
+// design rules, at the limits the rules name. Each rule line says which rule its
+// failures feed. The plugin never writes this file into a repository: the
+// repository's owners copy it, or the parts they want, beside eslint.config.js
+// and spread it into the exported array:
+//
+//   import ldd from './eslint.config.ldd.mjs'
+//   export default [...yourConfig, ...ldd]
+//
+// residue-exempt: an ESLint configuration names its plugins and rules on purpose.
+// It needs eslint-plugin-sonarjs, eslint-plugin-react, eslint-plugin-react-hooks,
+// eslint-plugin-promise, eslint-plugin-import and typescript-eslint; a repository
+// that does not use one of them leaves its rules out. Limits a repository already
+// sets stay the repository's: the linter is the authority for every threshold it
+// holds. Rules this file leaves out (style, imports, formatting) are the
+// repository's own choice.
+//
+// Adopt it on an existing codebase with ESLint's bulk suppressions: run
+// `npx eslint --suppress-all` once to record today's violations, so only new ones
+// fail; `npx eslint --prune-suppressions` drops the entries that are fixed.
+
+import importPlugin from 'eslint-plugin-import'
+import promise from 'eslint-plugin-promise'
+import react from 'eslint-plugin-react'
+import reactHooks from 'eslint-plugin-react-hooks'
+import sonarjs from 'eslint-plugin-sonarjs'
+import tseslint from 'typescript-eslint'
+
+export default [
+  {
+    files: ['**/*.{ts,tsx}'],
+    plugins: {
+      '@typescript-eslint': tseslint.plugin,
+      import: importPlugin,
+      promise,
+      react,
+      'react-hooks': reactHooks,
+      sonarjs,
+    },
+    rules: {
+      // R3 storifying
+      'sonarjs/cognitive-complexity': ['error', 15],
+      'sonarjs/cyclomatic-complexity': ['error', { threshold: 10 }],
+      'sonarjs/expression-complexity': ['error', { max: 5 }],
+      'sonarjs/max-lines-per-function': ['error', { maximum: 200 }],
+      'sonarjs/nested-control-flow': ['error', { maximumNestingLevel: 4 }],
+      'sonarjs/no-nested-conditional': 'error',
+      'sonarjs/no-nested-functions': 'error',
+      'sonarjs/elseif-without-else': 'error',
+      'react/no-unstable-nested-components': 'error',
+      // R1 primitive obsession
+      'max-params': ['error', 4],
+      'sonarjs/no-duplicate-string': ['error', { threshold: 3 }],
+      'sonarjs/max-union-size': ['error', { threshold: 4 }],
+      'sonarjs/no-identical-functions': 'error',
+      // R2 self-validating types: parse at the boundary
+      '@typescript-eslint/no-explicit-any': 'error',
+      '@typescript-eslint/no-non-null-assertion': 'error',
+      // R5 vertical slice: one juicy module per file; counts code lines only
+      'sonarjs/max-lines': ['error', { maximum: 450 }],
+      'react/no-multi-comp': ['error', { ignoreStateless: false }],
+      // R8 no globals
+      'import/no-mutable-exports': 'error',
+      // R10 concurrency safety
+      'react-hooks/exhaustive-deps': 'error',
+      '@typescript-eslint/no-floating-promises': 'error',
+      '@typescript-eslint/no-misused-promises': 'error',
+      'promise/catch-or-return': 'error',
+      // R11 conditional dispatch
+      '@typescript-eslint/switch-exhaustiveness-check': 'error',
+      'sonarjs/no-nested-switch': 'error',
+      'sonarjs/max-switch-cases': 'error',
+      'sonarjs/no-small-switch': 'error',
+      // R12 mutation discipline
+      'no-param-reassign': ['error', { props: true }],
+      'sonarjs/prefer-read-only-props': 'error',
+      'react/no-direct-mutation-state': 'error',
+    },
+  },
+  {
+    // Tests are long and repeat literals by design.
+    files: ['**/*.test.{ts,tsx}', '**/*.spec.{ts,tsx}'],
+    rules: {
+      'sonarjs/max-lines-per-function': 'off',
+      'sonarjs/no-duplicate-string': 'off',
+      'sonarjs/no-nested-functions': 'off',
+      'max-params': 'off',
+      'react/no-multi-comp': 'off',
+      '@typescript-eslint/no-non-null-assertion': 'off',
+    },
+  },
+]
diff --git a/go-linter-driven-development/setup/golangci.yaml b/go-linter-driven-development/setup/golangci.yaml
new file mode 100644
index 0000000..da5ef91
--- /dev/null
+++ b/go-linter-driven-development/setup/golangci.yaml
@@ -0,0 +1,82 @@
+# Recommended golangci-lint v2 configuration of the linter-driven-development
+# plugins: every linter rule the plugin's routing table routes to one of the
+# twelve design rules, at the limits the rules name. Each linter line says which
+# rule its failures feed. The plugin never writes this file into a repository:
+# the repository's owners copy it, or the parts they want, into .golangci.yaml.
+# residue-exempt: a golangci-lint configuration names its linters on purpose.
+#
+# Limits a repository already sets stay the repository's: the linter is the
+# authority for every threshold it holds. Rules this file leaves out (style,
+# naming, formatting) are the repository's own choice.
+#
+# Adopt it on an existing codebase with the ratchet below: only issues in code
+# changed since the merge base with main fail, so old code is not a wall of
+# findings on day one. Remove the ratchet once the old findings are gone.
+
+version: "2"
+
+issues:
+  new-from-merge-base: main
+
+linters:
+  default: none
+  enable:
+    - gocyclo           # R3 storifying: cyclomatic complexity
+    - gocognit          # R3 storifying: cognitive complexity
+    - funlen            # R3 storifying: function length
+    - nestif            # R3 storifying: nesting depth
+    - maintidx          # R3 storifying, R1 types: maintainability index
+    - dupl              # R1 types: duplicated logic; a duplicated switch is R11
+    - exhaustive        # R11 conditional dispatch: missing enum cases
+    - gochecknoglobals  # R8 no globals
+    - gochecknoinits    # R8 no globals
+    - ireturn           # R6 test-only interfaces: a constructor that returns an interface
+    - govet             # R10 concurrency: copylocks
+    - revive            # R1 types, R5 vertical slice: the rules below
+    - errcheck          # mechanical: an error that is not handled
+    - wrapcheck         # mechanical: an error without the context of its layer
+    - goconst           # mechanical; an enum-shaped string is R1's "Name enum strings"
+  settings:
+    gocyclo:
+      min-complexity: 10
+    gocognit:
+      min-complexity: 15
+    funlen:
+      lines: 50
+      statements: 40
+    nestif:
+      min-complexity: 2
+    maintidx:
+      under: 20
+    dupl:
+      threshold: 100
+    exhaustive:
+      # A default branch does not count as handling a case: every new case is
+      # handled where the switch is.
+      default-signifies-exhaustive: false
+    govet:
+      enable:
+        - copylocks
+    goconst:
+      min-len: 3
+      min-occurrences: 3
+    revive:
+      rules:
+        - name: argument-limit          # R1: more than 4 parameters wants a parameter object
+          arguments: [4]
+        - name: function-result-limit   # R1: more than 3 results wants a named result type
+          arguments: [3]
+        - name: file-length-limit       # R5: one juicy type per file; counts code lines only
+          arguments: [{max: 450, skip-comments: true, skip-blank-lines: true}]
+        - name: early-return            # mechanical: invert the condition and return early
+  exclusions:
+    rules:
+      # Tests are long and repeat literals by design.
+      - path: _test\.go
+        linters:
+          - funlen
+          - gocognit
+          - gocyclo
+          - maintidx
+          - dupl
+          - goconst
diff --git a/go-linter-driven-development/setup/ruff.toml b/go-linter-driven-development/setup/ruff.toml
new file mode 100644
index 0000000..36ce201
--- /dev/null
+++ b/go-linter-driven-development/setup/ruff.toml
@@ -0,0 +1,53 @@
+# Recommended ruff configuration of the linter-driven-development plugins:
+# every rule the plugin's routing table routes to one of the twelve design
+# rules, at the limits the rules name. Each rule says which rule its failures
+# feed. The plugin never writes this file into a repository: the repository's
+# owners copy it, or the parts they want, into ruff.toml, or into
+# pyproject.toml with each table name prefixed by "tool.ruff." ([lint] becomes
+# [tool.ruff.lint]).
+# residue-exempt: a ruff configuration names its rule codes on purpose.
+#
+# Limits a repository already sets stay the repository's: the linter is the
+# authority for every threshold it holds. Rules this file leaves out (style,
+# docstrings, imports) are the repository's own choice. ruff has no file-length
+# rule: the plugin's gap linter, scripts/ldd-lint.sh file-length, holds that
+# limit at 450 code lines.
+#
+# Adopt it on an existing codebase one change at a time: run ruff on the files
+# changed since the merge base with main, so old code is not a wall of
+# findings on day one:
+#   git diff --name-only --diff-filter=d "$(git merge-base HEAD main)" -- '*.py' | xargs ruff check
+
+[lint]
+# PLR1702 (nested blocks) is a preview rule.
+preview = true
+explicit-preview-rules = true
+extend-select = [
+  "C901",     # R3 storifying: complexity
+  "PLR0911",  # R3 storifying: too many returns
+  "PLR0912",  # R3 storifying: too many branches
+  "PLR0915",  # R3 storifying: too many statements
+  "PLR1702",  # R3 storifying: nesting
+  "PLR0913",  # R1 types: too many arguments wants a parameter object
+  "PLR2004",  # R1 types: a magic value; an enum-shaped string is "Name enum strings"
+  "FBT001",   # R11 conditional dispatch: a boolean positional parameter
+  "FBT002",   # R11 conditional dispatch: a boolean default parameter
+  "PLW0603",  # R8 no globals: a global statement
+  "B006",     # R12 mutation discipline: a mutable default argument
+  "B008",     # R12 mutation discipline: a call in a default argument
+]
+
+[lint.mccabe]
+max-complexity = 8
+
+[lint.pylint]
+max-args = 4          # self and cls are not counted
+max-branches = 12
+max-returns = 6
+max-statements = 50
+max-nested-blocks = 5
+
+[lint.per-file-ignores]
+# Tests repeat literals and take many fixtures by design.
+"**/test_*.py" = ["PLR2004", "PLR0913", "FBT001", "FBT002"]
+"**/*_test.py" = ["PLR2004", "PLR0913", "FBT001", "FBT002"]
diff --git a/lang/generic/passthrough/CHANGELOG.md b/lang/generic/passthrough/CHANGELOG.md
index 1befcfe..80a0749 100644
--- a/lang/generic/passthrough/CHANGELOG.md
+++ b/lang/generic/passthrough/CHANGELOG.md
@@ -7,6 +7,15 @@ Format based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); versio
 
 ### Added
 
+- **A recommended linter setup.** `setup/golangci.yaml`, `setup/ruff.toml` and
+  `setup/eslint.config.ldd.mjs` enable every linter rule the routing table routes to
+  a design rule, at the limits the rules name, with a way to adopt each on an
+  existing codebase: golangci-lint's merge-base ratchet, ESLint's bulk
+  suppressions, and ruff on changed files. The plugin never writes them into a
+  repository. The gap linter's threshold line names the file and rule that would
+  hold a file-length limit; for Python, where ruff has no file-length rule, it says
+  that the gap linter holds it.
+
 - **A gap linter for the design triggers no linter holds.** `scripts/ldd-lint.sh`
   measures lines per source file (`file-length`) and source files per directory
   (`package-size`). Where the repository's linter config names a file-length rule,
@@ -27,6 +36,10 @@ Format based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); versio
 
 ### Fixed
 
+- **The gap linter runs under bash 3.2.** macOS's `/bin/bash` stopped
+  `ldd-lint.sh` with a syntax error: bash 3.2 misreads a `case` pattern inside a
+  process substitution. The script now runs under bash 3.2 and bash 5.
+
 - **A value-taking option given last no longer hangs the review scripts.** When
   `ldd-detect.sh` or `ldd-scope.sh` got an option such as `--root` or `--base` as
   its last argument, the script looped forever. It now stops with "<option> needs
diff --git a/lang/generic/passthrough/README.md b/lang/generic/passthrough/README.md
index bf11dbf..854826c 100644
--- a/lang/generic/passthrough/README.md
+++ b/lang/generic/passthrough/README.md
@@ -47,6 +47,11 @@ phase is exactly as strong as your repository's own linter configuration:
   invokes — `golangci-lint`, `ruff`, `eslint`, `clippy`, `checkstyle` — via the
   Taskfile, Makefile or package script that invokes it. It never installs or runs a
   linter the repository does not use.
+- **It ships a recommended setup for Go, Python and TypeScript.** `setup/` in the
+  plugin directory holds `golangci.yaml`, `ruff.toml` and `eslint.config.ldd.mjs`:
+  every linter rule the routing table routes to a design rule, at the limits the
+  rules name. The plugin never writes them into your repository: copy one, or the
+  parts you want. Limits your configuration already sets stay yours.
 - **It routes findings by what they are about.** The refactoring skill's routing
   table is keyed by finding family — complexity, function length, nesting,
   duplicated code, non-exhaustive switch, globals, single-implementation interfaces,
diff --git a/lang/generic/scripts/ldd-fixture.sh b/lang/generic/scripts/ldd-fixture.sh
index 6ae87c2..d315b53 100644
--- a/lang/generic/scripts/ldd-fixture.sh
+++ b/lang/generic/scripts/ldd-fixture.sh
@@ -18,6 +18,9 @@
 #   FX_BLOCK_OPEN      the line that opens a block comment, "" when the
 #   FX_BLOCK_CLOSE     language has none, and the line that closes it
 #   FX_SKIP_FILES      source file names a directory count leaves out
+#   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
+#                      the file-length limit, and FX_LENGTH_RULE its rule; both
+#                      "" when the language's linter has no file-length rule
 #   fx_test_file <dir> <n>             a test file's path in <dir>
 #   FX_LINTER_CONFIG   the path, under the repository root, of the file that
 #                      fx_write_linter_config writes, and FX_LINTER_COMMENT the
@@ -35,6 +38,8 @@ use_row() {
   case "$1" in
     go)
       FX_LINTER_CONFIG='.golangci.yml'
+      FX_SETUP_FILE='golangci.yaml'
+      FX_LENGTH_RULE='file-length-limit'
       FX_LINTER_COMMENT='#'
       FX_EXT='.go'
       FX_LINE_COMMENT='// note'
@@ -47,6 +52,8 @@ use_row() {
       ;;
     python)
       FX_LINTER_CONFIG='.pylintrc'
+      FX_SETUP_FILE=''
+      FX_LENGTH_RULE=''
       FX_LINTER_COMMENT=';'
       FX_EXT='.py'
       FX_LINE_COMMENT='# note'
diff --git a/lang/go/passthrough/CHANGELOG.md b/lang/go/passthrough/CHANGELOG.md
index 36bff47..ef2e41a 100644
--- a/lang/go/passthrough/CHANGELOG.md
+++ b/lang/go/passthrough/CHANGELOG.md
@@ -7,6 +7,15 @@ Format based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); versio
 
 ### Added
 
+- **A recommended linter setup.** `setup/golangci.yaml`, `setup/ruff.toml` and
+  `setup/eslint.config.ldd.mjs` enable every linter rule the routing table routes to
+  a design rule, at the limits the rules name, with a way to adopt each on an
+  existing codebase: golangci-lint's merge-base ratchet, ESLint's bulk
+  suppressions, and ruff on changed files. The plugin never writes them into a
+  repository. The gap linter's threshold line names the file and rule that would
+  hold a file-length limit; for Python, where ruff has no file-length rule, it says
+  that the gap linter holds it.
+
 - **A gap linter for the design triggers no linter holds.** `scripts/ldd-lint.sh`
   measures lines per source file (`file-length`) and source files per directory
   (`package-size`). Where the repository's linter config names a file-length rule,
@@ -33,6 +42,10 @@ Format based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); versio
 
 ### Fixed
 
+- **The gap linter runs under bash 3.2.** macOS's `/bin/bash` stopped
+  `ldd-lint.sh` with a syntax error: bash 3.2 misreads a `case` pattern inside a
+  process substitution. The script now runs under bash 3.2 and bash 5.
+
 - **A value-taking option given last no longer hangs the review scripts.** When
   `ldd-detect.sh` or `ldd-scope.sh` got an option such as `--root` or `--base` as
   its last argument, the script looped forever. It now stops with "<option> needs
diff --git a/lang/go/passthrough/README.md b/lang/go/passthrough/README.md
index 5c15ab5..b7f0d41 100644
--- a/lang/go/passthrough/README.md
+++ b/lang/go/passthrough/README.md
@@ -209,7 +209,9 @@ Should show: `go-linter-driven-development (enabled)`
 
 The scenario guide — the easiest start first, then code you already wrote, a plan you already have, and running the plugin from a subagent — is [docs/quick-start.md](https://github.com/buzzdan/ai-coding-rules/blob/main/docs/quick-start.md) in the main repository.
 
-**Zero configuration required.** The plugin discovers your project's test and lint commands from `README.md`, `CLAUDE.md`, `Makefile`, or `Taskfile.yaml`. Just install and go.
+**Zero configuration to run.** The plugin discovers your project's test and lint commands from `README.md`, `CLAUDE.md`, `Makefile`, or `Taskfile.yaml`. Just install and go.
+
+**The recommended setup makes the design triggers fire.** `setup/golangci.yaml` in the plugin directory enables every linter the routing table routes to a design rule, at the limits the rules name, with a ratchet so only new code fails at first. The plugin never writes it into your repository: copy it, or the parts you want, into `.golangci.yaml`. Limits your configuration already sets stay yours.
 
 ### The Easiest Way: Just Talk to It
 
diff --git a/lang/go/scripts/ldd-fixture.sh b/lang/go/scripts/ldd-fixture.sh
index d437f89..2ddfac6 100644
--- a/lang/go/scripts/ldd-fixture.sh
+++ b/lang/go/scripts/ldd-fixture.sh
@@ -18,6 +18,9 @@
 #   FX_BLOCK_OPEN      the line that opens a block comment, "" when the
 #   FX_BLOCK_CLOSE     language has none, and the line that closes it
 #   FX_SKIP_FILES      source file names a directory count leaves out
+#   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
+#                      the file-length limit, and FX_LENGTH_RULE its rule; both
+#                      "" when the language's linter has no file-length rule
 #   fx_test_file <dir> <n>             a test file's path in <dir>
 #   FX_LINTER_CONFIG   the path, under the repository root, of the file that
 #                      fx_write_linter_config writes, and FX_LINTER_COMMENT the
@@ -33,6 +36,8 @@ FX_NATIVE="go"
 
 use_row() {
   FX_LINTER_CONFIG='.golangci.yaml'
+  FX_SETUP_FILE='golangci.yaml'
+  FX_LENGTH_RULE='file-length-limit'
   FX_LINTER_COMMENT='#'
   FX_EXT='.go'
   FX_LINE_COMMENT='// note'
diff --git a/lang/python/passthrough/CHANGELOG.md b/lang/python/passthrough/CHANGELOG.md
index 380c0df..1d8d852 100644
--- a/lang/python/passthrough/CHANGELOG.md
+++ b/lang/python/passthrough/CHANGELOG.md
@@ -7,6 +7,15 @@ Format based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); versio
 
 ### Added
 
+- **A recommended linter setup.** `setup/golangci.yaml`, `setup/ruff.toml` and
+  `setup/eslint.config.ldd.mjs` enable every linter rule the routing table routes to
+  a design rule, at the limits the rules name, with a way to adopt each on an
+  existing codebase: golangci-lint's merge-base ratchet, ESLint's bulk
+  suppressions, and ruff on changed files. The plugin never writes them into a
+  repository. The gap linter's threshold line names the file and rule that would
+  hold a file-length limit; for Python, where ruff has no file-length rule, it says
+  that the gap linter holds it.
+
 - **A gap linter for the design triggers no linter holds.** `scripts/ldd-lint.sh`
   measures lines per source file (`file-length`) and source files per directory
   (`package-size`). Where the repository's linter config names a file-length rule,
@@ -27,6 +36,10 @@ Format based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); versio
 
 ### Fixed
 
+- **The gap linter runs under bash 3.2.** macOS's `/bin/bash` stopped
+  `ldd-lint.sh` with a syntax error: bash 3.2 misreads a `case` pattern inside a
+  process substitution. The script now runs under bash 3.2 and bash 5.
+
 - **A value-taking option given last no longer hangs the review scripts.** When
   `ldd-detect.sh` or `ldd-scope.sh` got an option such as `--root` or `--base` as
   its last argument, the script looped forever. It now stops with "<option> needs
diff --git a/lang/python/passthrough/README.md b/lang/python/passthrough/README.md
index 762721b..5c3af42 100644
--- a/lang/python/passthrough/README.md
+++ b/lang/python/passthrough/README.md
@@ -98,9 +98,15 @@ checker the repository does not use.
   `PLR0913` to R1, `PLW0603` to R8, `FBT` to R11, `B006`/`B008` to R12. The
   mechanical row — `ARG`, `SIM`, `RET`, `B904`, `BLE001`, `PLR2004`, import order,
   style — is fixed by the lint-fixer in an isolated context.
-- **Some findings have no ruff rule.** Duplicated code, file length, a `match`
-  missing enum cases, a `Protocol` with one implementer and shared-state races are
-  review findings: the hunters own them alone.
+- **Some findings have no ruff rule.** Duplicated code, a `match` missing enum
+  cases, a `Protocol` with one implementer and shared-state races are review
+  findings: the hunters own them alone. File length has no ruff rule either: the
+  gap linter, `scripts/ldd-lint.sh file-length`, measures it.
+- **The recommended setup makes the design triggers fire.** `setup/ruff.toml` in the
+  plugin directory selects every ruff rule the routing table routes to a design
+  rule, at the limits the rules name. The plugin never writes it into your
+  repository: copy it, or the parts you want, into `ruff.toml` or `pyproject.toml`.
+  Limits your configuration already sets stay yours.
 - **`# noqa`, `# ty: ignore` and `# type: ignore` are all suppressions.** The lint-fixer
   never adds one and never edits `[tool.ruff]`, `[tool.ty]` or `[tool.mypy]`; a new
   one in a diff is itself a review finding.
diff --git a/lang/python/scripts/ldd-fixture.sh b/lang/python/scripts/ldd-fixture.sh
index c900020..9d6eabf 100644
--- a/lang/python/scripts/ldd-fixture.sh
+++ b/lang/python/scripts/ldd-fixture.sh
@@ -18,6 +18,9 @@
 #   FX_BLOCK_OPEN      the line that opens a block comment, "" when the
 #   FX_BLOCK_CLOSE     language has none, and the line that closes it
 #   FX_SKIP_FILES      source file names a directory count leaves out
+#   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
+#                      the file-length limit, and FX_LENGTH_RULE its rule; both
+#                      "" when the language's linter has no file-length rule
 #   fx_test_file <dir> <n>             a test file's path in <dir>
 #   FX_LINTER_CONFIG   the path, under the repository root, of the file that
 #                      fx_write_linter_config writes, and FX_LINTER_COMMENT the
@@ -33,6 +36,8 @@ FX_NATIVE="python"
 
 use_row() {
   FX_LINTER_CONFIG='pyproject.toml'
+  FX_SETUP_FILE=''
+  FX_LENGTH_RULE=''
   FX_LINTER_COMMENT='#'
   FX_EXT='.py'
   FX_LINE_COMMENT='# note'
diff --git a/lang/ts-react/passthrough/CHANGELOG.md b/lang/ts-react/passthrough/CHANGELOG.md
index d4d78ed..a452a3a 100644
--- a/lang/ts-react/passthrough/CHANGELOG.md
+++ b/lang/ts-react/passthrough/CHANGELOG.md
@@ -7,6 +7,15 @@ Format based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); versio
 
 ### Added
 
+- **A recommended linter setup.** `setup/golangci.yaml`, `setup/ruff.toml` and
+  `setup/eslint.config.ldd.mjs` enable every linter rule the routing table routes to
+  a design rule, at the limits the rules name, with a way to adopt each on an
+  existing codebase: golangci-lint's merge-base ratchet, ESLint's bulk
+  suppressions, and ruff on changed files. The plugin never writes them into a
+  repository. The gap linter's threshold line names the file and rule that would
+  hold a file-length limit; for Python, where ruff has no file-length rule, it says
+  that the gap linter holds it.
+
 - **A gap linter for the design triggers no linter holds.** `scripts/ldd-lint.sh`
   measures lines per source file (`file-length`) and source files per directory
   (`package-size`). Where the repository's linter config names a file-length rule,
@@ -27,6 +36,10 @@ Format based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); versio
 
 ### Fixed
 
+- **The gap linter runs under bash 3.2.** macOS's `/bin/bash` stopped
+  `ldd-lint.sh` with a syntax error: bash 3.2 misreads a `case` pattern inside a
+  process substitution. The script now runs under bash 3.2 and bash 5.
+
 - **A value-taking option given last no longer hangs the review scripts.** When
   `ldd-detect.sh` or `ldd-scope.sh` got an option such as `--root` or `--base` as
   its last argument, the script looped forever. It now stops with "<option> needs
diff --git a/lang/ts-react/passthrough/README.md b/lang/ts-react/passthrough/README.md
index a0498f2..26f9bba 100644
--- a/lang/ts-react/passthrough/README.md
+++ b/lang/ts-react/passthrough/README.md
@@ -142,6 +142,11 @@ adds a checker the repository does not use.
   `@ts-expect-error`, `@ts-ignore`, `@ts-nocheck` and `// prettier-ignore`. The
   lint-fixer never adds one and never edits `eslint.config.*`, `tsconfig*.json` or
   `.prettierrc*`; a new one in a diff is itself a review finding.
+- **The recommended setup makes the design triggers fire.** `setup/eslint.config.ldd.mjs`
+  in the plugin directory is a flat-config fragment with every rule the routing
+  table routes to a design rule, at the limits the rules name. The plugin never
+  writes it into your repository: copy it beside `eslint.config.js` and spread it
+  into the exported array. Limits your configuration already sets stay yours.
 - **What it does not review.** Accessibility beyond what `jsx-a11y` flags —
   contrast, heading order, focus management, live regions — is the repository's
   axe run, which this plugin does not replace. Error-boundary placement and
diff --git a/lang/ts-react/scripts/ldd-fixture.sh b/lang/ts-react/scripts/ldd-fixture.sh
index aa24553..6f70b96 100644
--- a/lang/ts-react/scripts/ldd-fixture.sh
+++ b/lang/ts-react/scripts/ldd-fixture.sh
@@ -18,6 +18,9 @@
 #   FX_BLOCK_OPEN      the line that opens a block comment, "" when the
 #   FX_BLOCK_CLOSE     language has none, and the line that closes it
 #   FX_SKIP_FILES      source file names a directory count leaves out
+#   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
+#                      the file-length limit, and FX_LENGTH_RULE its rule; both
+#                      "" when the language's linter has no file-length rule
 #   fx_test_file <dir> <n>             a test file's path in <dir>
 #   FX_LINTER_CONFIG   the path, under the repository root, of the file that
 #                      fx_write_linter_config writes, and FX_LINTER_COMMENT the
@@ -36,6 +39,8 @@ FX_NATIVE="typescript"
 # Every file the row writes is a `.ts` file, so both globs select the same set.
 use_row() {
   FX_LINTER_CONFIG='eslint.config.mjs'
+  FX_SETUP_FILE='eslint.config.ldd.mjs'
+  FX_LENGTH_RULE='sonarjs/max-lines'
   FX_LINTER_COMMENT='//'
   FX_EXT='.ts'
   FX_LINE_COMMENT='// note'
diff --git a/linter-driven-development/CHANGELOG.md b/linter-driven-development/CHANGELOG.md
index 1befcfe..80a0749 100644
--- a/linter-driven-development/CHANGELOG.md
+++ b/linter-driven-development/CHANGELOG.md
@@ -7,6 +7,15 @@ Format based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); versio
 
 ### Added
 
+- **A recommended linter setup.** `setup/golangci.yaml`, `setup/ruff.toml` and
+  `setup/eslint.config.ldd.mjs` enable every linter rule the routing table routes to
+  a design rule, at the limits the rules name, with a way to adopt each on an
+  existing codebase: golangci-lint's merge-base ratchet, ESLint's bulk
+  suppressions, and ruff on changed files. The plugin never writes them into a
+  repository. The gap linter's threshold line names the file and rule that would
+  hold a file-length limit; for Python, where ruff has no file-length rule, it says
+  that the gap linter holds it.
+
 - **A gap linter for the design triggers no linter holds.** `scripts/ldd-lint.sh`
   measures lines per source file (`file-length`) and source files per directory
   (`package-size`). Where the repository's linter config names a file-length rule,
@@ -27,6 +36,10 @@ Format based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); versio
 
 ### Fixed
 
+- **The gap linter runs under bash 3.2.** macOS's `/bin/bash` stopped
+  `ldd-lint.sh` with a syntax error: bash 3.2 misreads a `case` pattern inside a
+  process substitution. The script now runs under bash 3.2 and bash 5.
+
 - **A value-taking option given last no longer hangs the review scripts.** When
   `ldd-detect.sh` or `ldd-scope.sh` got an option such as `--root` or `--base` as
   its last argument, the script looped forever. It now stops with "<option> needs
diff --git a/linter-driven-development/README.md b/linter-driven-development/README.md
index bf11dbf..854826c 100644
--- a/linter-driven-development/README.md
+++ b/linter-driven-development/README.md
@@ -47,6 +47,11 @@ phase is exactly as strong as your repository's own linter configuration:
   invokes — `golangci-lint`, `ruff`, `eslint`, `clippy`, `checkstyle` — via the
   Taskfile, Makefile or package script that invokes it. It never installs or runs a
   linter the repository does not use.
+- **It ships a recommended setup for Go, Python and TypeScript.** `setup/` in the
+  plugin directory holds `golangci.yaml`, `ruff.toml` and `eslint.config.ldd.mjs`:
+  every linter rule the routing table routes to a design rule, at the limits the
+  rules name. The plugin never writes them into your repository: copy one, or the
+  parts you want. Limits your configuration already sets stay yours.
 - **It routes findings by what they are about.** The refactoring skill's routing
   table is keyed by finding family — complexity, function length, nesting,
   duplicated code, non-exhaustive switch, globals, single-implementation interfaces,
diff --git a/linter-driven-development/scripts/ldd-detect_test.sh b/linter-driven-development/scripts/ldd-detect_test.sh
index 8e1c887..7b23daf 100644
--- a/linter-driven-development/scripts/ldd-detect_test.sh
+++ b/linter-driven-development/scripts/ldd-detect_test.sh
@@ -141,6 +141,9 @@ questions_in_rules() {
 #   FX_BLOCK_OPEN      the line that opens a block comment, "" when the
 #   FX_BLOCK_CLOSE     language has none, and the line that closes it
 #   FX_SKIP_FILES      source file names a directory count leaves out
+#   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
+#                      the file-length limit, and FX_LENGTH_RULE its rule; both
+#                      "" when the language's linter has no file-length rule
 #   fx_test_file <dir> <n>             a test file's path in <dir>
 #   FX_LINTER_CONFIG   the path, under the repository root, of the file that
 #                      fx_write_linter_config writes, and FX_LINTER_COMMENT the
@@ -158,6 +161,8 @@ use_row() {
   case "$1" in
     go)
       FX_LINTER_CONFIG='.golangci.yml'
+      FX_SETUP_FILE='golangci.yaml'
+      FX_LENGTH_RULE='file-length-limit'
       FX_LINTER_COMMENT='#'
       FX_EXT='.go'
       FX_LINE_COMMENT='// note'
@@ -170,6 +175,8 @@ use_row() {
       ;;
     python)
       FX_LINTER_CONFIG='.pylintrc'
+      FX_SETUP_FILE=''
+      FX_LENGTH_RULE=''
       FX_LINTER_COMMENT=';'
       FX_EXT='.py'
       FX_LINE_COMMENT='# note'
diff --git a/linter-driven-development/scripts/ldd-lint.sh b/linter-driven-development/scripts/ldd-lint.sh
index c0252a3..98ea9af 100755
--- a/linter-driven-development/scripts/ldd-lint.sh
+++ b/linter-driven-development/scripts/ldd-lint.sh
@@ -338,9 +338,15 @@ lang_is_test() {
 #                                   nothing. A named rule belongs to the linter:
 #                                   its limit, its counting and whether it is on
 #                                   are the repository's decision.
-#   lint_file_length_snippet <id> <max>  the linter setting that would hold the
-#                                   limit, or the .ldd-lint.yaml entry when no
-#                                   linter rule is known: text to propose
+#   lint_setup_files                one line per recommended config under the
+#                                   plugin's setup/: file TAB the tool that checks it
+#   lint_setup_check <file> <setup dir> <work dir>  run that tool's own check of
+#                                   the file; exit 0 when the tool accepts it
+#   lint_file_length_proposal <id>  what would hold the limit in the
+#                                   repository's linter: the rule, named after
+#                                   the plugin's recommended config under setup/
+#                                   that sets it, or the .ldd-lint.yaml entry when
+#                                   the language's linter has no such rule
 
 lint_comment_style() {
   case "$1" in
@@ -443,12 +449,27 @@ lint_file_length_rule() {
   return 0
 }
 
-lint_file_length_snippet() {
+lint_setup_files() {
+  printf 'golangci.yaml\tgolangci-lint\n'
+  printf 'ruff.toml\truff\n'
+  printf 'eslint.config.ldd.mjs\tnode\n'
+}
+
+lint_setup_check() { # <file> <setup dir> <work dir>
+  case "$1" in
+    golangci.yaml)         golangci-lint config verify -c "$2/$1" ;;
+    ruff.toml)             printf 'x = 1\n' > "$3/ldd_setup_check.py" && (cd "$3" && ruff check --no-cache --config "$2/$1" ldd_setup_check.py) ;;
+    eslint.config.ldd.mjs) node --check "$2/$1" ;;
+    *)                     return 2 ;;
+  esac
+}
+
+lint_file_length_proposal() {
   case "$1" in
-    go)                    printf "revive in .golangci.yaml: - name: file-length-limit, arguments: [{max: %s, skip-comments: true, skip-blank-lines: true}]" "$2" ;;
-    typescript|javascript) printf "the eslint config: 'sonarjs/max-lines': ['error', { maximum: %s }]" "$2" ;;
-    python)                printf "pyproject.toml: [tool.pylint.format] max-module-lines = %s (pylint counts every line, comments and blank lines too)" "$2" ;;
-    *)                     printf "no linter rule is known for %s; a .ldd-lint.yaml entry file_max_lines: %s would state this limit" "$1" "$2" ;;
+    go)                    printf "a setting to propose, never to add on your own: revive file-length-limit, as the plugin's setup/golangci.yaml sets it" ;;
+    typescript|javascript) printf "a setting to propose, never to add on your own: sonarjs/max-lines, as the plugin's setup/eslint.config.ldd.mjs sets it" ;;
+    python)                printf "ruff has no file-length rule, so this script holds the limit; a .ldd-lint.yaml entry file_max_lines: <n> states another" ;;
+    *)                     printf "no linter rule is known for %s; a .ldd-lint.yaml entry file_max_lines: <n> states another limit" "$1" ;;
   esac
 }
 # ================== end linter table ==================
@@ -520,6 +541,16 @@ trap 'rm -f "$SCOPE" "$INVENTORY"' EXIT
 list_candidates | by_language > "$SCOPE"
 if [[ -n "$FILES_LIST" ]]; then list_repo | by_language > "$INVENTORY"; else cp "$SCOPE" "$INVENTORY"; fi
 
+# dir_of <path> — the directory part of a relative path, "." for a file at
+# the root. A function, because bash 3.2 misreads a case pattern's ")" inside
+# a process substitution.
+dir_of() {
+  case "$1" in
+    */*) printf '%s\n' "${1%/*}" ;;
+    *)   printf '.\n' ;;
+  esac
+}
+
 # measured <path> — exit 0 when the file counts for this language: not under
 # an excluded directory, not a test, not generated. Every path the script
 # hands to find, head or awk starts with "./", and a directory is cut from a
@@ -551,7 +582,7 @@ run_file_length() { # <id> — every measured file of that language
     say "threshold: $id file length — set by $OVERRIDE_FILE ($max code lines)"
   else
     max="$DEFAULT_FILE_MAX_LINES"; src="profile default"
-    say "threshold: $id file length — profile default ($max code lines); the repository's linter does not hold it; a setting to propose, never to add on your own: $(lint_file_length_snippet "$id" "$max")"
+    say "threshold: $id file length — profile default ($max code lines); the repository's linter does not hold it; $(lint_file_length_proposal "$id")"
   fi
   while IFS=$'\t' read -r _ f; do
     measured "$f" || continue
@@ -575,7 +606,7 @@ run_package_size() { # <id> — every directory that holds a measured file of th
   awk -F'\t' -v id="$id" '$1 == id { print $2 }' "$INVENTORY" | while IFS= read -r f; do
     [[ -n "$skip" ]] && printf '%s\n' "$f" | grep -qE -- "$skip" && continue
     measured "$f" || continue
-    case "$f" in */*) printf '%s\n' "${f%/*}" ;; *) printf '.\n' ;; esac
+    dir_of "$f"
   done | LC_ALL=C sort | uniq -c | awk '{ n = $1; sub(/^[ \t]*[0-9]+[ \t]/, ""); print $0 "\t" n }' > "$counts"
   while IFS= read -r d; do
     n=$(awk -F'\t' -v d="$d" '$1 == d { print $2; exit }' "$counts")
@@ -586,8 +617,7 @@ run_package_size() { # <id> — every directory that holds a measured file of th
       finding "$d" "$n source files (warning at $warn, $src)"
     fi
   done < <(awk -F'\t' -v id="$id" '$1 == id { print $2 }' "$SCOPE" | while IFS= read -r f; do
-             measured "$f" || continue
-             case "$f" in */*) printf '%s\n' "${f%/*}" ;; *) printf '.\n' ;; esac
+             measured "$f" && dir_of "$f"
            done | LC_ALL=C sort -u)
   rm -f "$counts"
 }
diff --git a/linter-driven-development/scripts/ldd-lint_test.sh b/linter-driven-development/scripts/ldd-lint_test.sh
index 962c198..1a1a7d8 100644
--- a/linter-driven-development/scripts/ldd-lint_test.sh
+++ b/linter-driven-development/scripts/ldd-lint_test.sh
@@ -105,6 +105,9 @@ fill_dir() {
 #   FX_BLOCK_OPEN      the line that opens a block comment, "" when the
 #   FX_BLOCK_CLOSE     language has none, and the line that closes it
 #   FX_SKIP_FILES      source file names a directory count leaves out
+#   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
+#                      the file-length limit, and FX_LENGTH_RULE its rule; both
+#                      "" when the language's linter has no file-length rule
 #   fx_test_file <dir> <n>             a test file's path in <dir>
 #   FX_LINTER_CONFIG   the path, under the repository root, of the file that
 #                      fx_write_linter_config writes, and FX_LINTER_COMMENT the
@@ -122,6 +125,8 @@ use_row() {
   case "$1" in
     go)
       FX_LINTER_CONFIG='.golangci.yml'
+      FX_SETUP_FILE='golangci.yaml'
+      FX_LENGTH_RULE='file-length-limit'
       FX_LINTER_COMMENT='#'
       FX_EXT='.go'
       FX_LINE_COMMENT='// note'
@@ -134,6 +139,8 @@ use_row() {
       ;;
     python)
       FX_LINTER_CONFIG='.pylintrc'
+      FX_SETUP_FILE=''
+      FX_LENGTH_RULE=''
       FX_LINTER_COMMENT=';'
       FX_EXT='.py'
       FX_LINE_COMMENT='# note'
@@ -241,6 +248,165 @@ fx_write_linter_config_other() {
   esac
 }
 
+# ==================== linter table ====================
+# What the gap linter needs to know per language id: how a comment is written,
+# which source files a directory count leaves out, and whether the
+# repository's own linter holds the file-length limit. The same table is
+# rendered into every plugin, so two plugins measure one file the same way.
+# residue-exempt: the table names every language's linter and config file on
+# purpose, the same in every rendering.
+#
+#   lint_comment_style <id>         c (// and /* */), d (also /+ +/) or hash (#)
+#   lint_strip_comments <style> <file>  the file with every comment removed and
+#                                   string literals kept, one output line per
+#                                   input line: a comment-only line prints empty.
+#                                   Styles: c, d, hash (# and triple-quoted
+#                                   strings), ini (# and a leading ;)
+#   lint_package_skip_re <id>       ERE over a relative path: source files a
+#                                   directory count leaves out (an index module,
+#                                   a package marker, generated stubs); "" for none
+#   lint_file_length_rule <id>      "<rule> in <config file>" when a linter config
+#                                   at the repository root names a file-length
+#                                   rule outside a comment, else
+#                                   nothing. A named rule belongs to the linter:
+#                                   its limit, its counting and whether it is on
+#                                   are the repository's decision.
+#   lint_setup_files                one line per recommended config under the
+#                                   plugin's setup/: file TAB the tool that checks it
+#   lint_setup_check <file> <setup dir> <work dir>  run that tool's own check of
+#                                   the file; exit 0 when the tool accepts it
+#   lint_file_length_proposal <id>  what would hold the limit in the
+#                                   repository's linter: the rule, named after
+#                                   the plugin's recommended config under setup/
+#                                   that sets it, or the .ldd-lint.yaml entry when
+#                                   the language's linter has no such rule
+
+lint_comment_style() {
+  case "$1" in
+    python|ruby|shell) printf 'hash' ;;
+    d)                 printf 'd' ;;
+    *)                 printf 'c' ;;
+  esac
+}
+
+lint_package_skip_re() {
+  case "$1" in
+    go)                    printf '%s' '(_gen|\.pb)\.go$' ;;
+    python)                printf '%s' '(^|/)(__init__|conftest)\.py$|_pb2(_grpc)?\.py$' ;;
+    typescript|javascript) printf '%s' '(^|/)index\.[cm]?[jt]sx?$|\.stories\.[cm]?[jt]sx?$' ;;
+  esac
+  return 0
+}
+
+# LINT_STRIP_AWK walks each line one character at a time. A quote opens a
+# string that a comment marker cannot end; single and double quotes close at
+# the end of the line, a backtick string (c and d) and a triple-quoted string
+# (hash) run on. A block comment may open after code and run on. The awk uses
+# substr and string compares only, so mawk, gawk and BSD awk read it alike.
+LINT_STRIP_AWK='
+BEGIN { bq = sprintf("%c", 96); sq = sprintf("%c", 39); dq = "\"" }
+{
+  line = $0; out = ""; n = length(line); i = 1
+  if (q == dq || q == sq) q = ""
+  while (i <= n) {
+    if (inblock) {
+      if (substr(line, i, length(closer)) == closer) { inblock = 0; i += length(closer); out = out " "; continue }
+      i++; continue
+    }
+    ch = substr(line, i, 1)
+    if (q != "") {
+      if (ch == "\\" && (q == dq || q == sq)) { out = out substr(line, i, 2); i += 2; continue }
+      if (substr(line, i, length(q)) == q) { out = out q; i += length(q); q = ""; continue }
+      out = out ch; i++; continue
+    }
+    if (style == "hash" || style == "ini") {
+      if (ch == "#") break
+      if (style == "ini" && ch == ";" && out ~ /^[ \t]*$/) break
+      three = substr(line, i, 3)
+      if (style == "hash" && (three == dq dq dq || three == sq sq sq)) { q = three; out = out three; i += 3; continue }
+    } else {
+      two = substr(line, i, 2)
+      if (two == "//") break
+      if (two == "/*" || (style == "d" && two == "/+")) { inblock = 1; closer = (two == "/+") ? "+/" : "*/"; out = out " "; i += 2; continue }
+      if (ch == bq) { q = bq; out = out ch; i++; continue }
+    }
+    if (ch == dq || ch == sq) { q = ch; out = out ch; i++; continue }
+    out = out ch; i++
+  }
+  print out
+}
+'
+
+lint_strip_comments() { # <style> <file>
+  awk -v style="$1" "$LINT_STRIP_AWK" "$2"
+}
+
+# _lint_config_style <config file> — how that config format writes a comment
+_lint_config_style() {
+  case "$1" in
+    *.yaml|*.yml|*.toml) printf 'hash' ;;
+    *.cfg|*.ini|.pylintrc|pylintrc) printf 'ini' ;;
+    *) printf 'c' ;;
+  esac
+}
+
+# _lint_names <ERE> <file>... — print the first file whose text outside its
+# comments matches the pattern
+_lint_names() {
+  local re="$1" f; shift
+  for f in "$@"; do
+    [[ -f "$f" ]] || continue
+    lint_strip_comments "$(_lint_config_style "$f")" "./$f" 2>/dev/null | grep -qE -- "$re" && { printf '%s' "$f"; return 0; }
+  done
+  return 1
+}
+
+lint_file_length_rule() {
+  local f
+  case "$1" in
+    go)
+      f=$(_lint_names 'file-length-limit' .golangci.yaml .golangci.yml .golangci.toml .golangci.json) \
+        && printf 'revive file-length-limit in %s' "$f" ;;
+    typescript|javascript)
+      local configs=(eslint.config.js eslint.config.mjs eslint.config.cjs eslint.config.ts eslint.config.mts eslint.config.cts
+                     .eslintrc .eslintrc.js .eslintrc.cjs .eslintrc.json .eslintrc.yml .eslintrc.yaml)
+      if f=$(_lint_names 'sonarjs/max-lines([^-a-zA-Z]|$)' "${configs[@]}"); then
+        printf 'sonarjs/max-lines in %s' "$f"
+      elif f=$(_lint_names '(^|[^-/a-zA-Z])max-lines([^-a-zA-Z]|$)' "${configs[@]}"); then
+        printf 'max-lines in %s' "$f"
+      fi ;;
+    python)
+      f=$(_lint_names '^[[:space:]]*max-module-lines[[:space:]]*=' pyproject.toml .pylintrc pylintrc setup.cfg tox.ini) \
+        && printf 'pylint max-module-lines in %s' "$f" ;;
+  esac
+  return 0
+}
+
+lint_setup_files() {
+  printf 'golangci.yaml\tgolangci-lint\n'
+  printf 'ruff.toml\truff\n'
+  printf 'eslint.config.ldd.mjs\tnode\n'
+}
+
+lint_setup_check() { # <file> <setup dir> <work dir>
+  case "$1" in
+    golangci.yaml)         golangci-lint config verify -c "$2/$1" ;;
+    ruff.toml)             printf 'x = 1\n' > "$3/ldd_setup_check.py" && (cd "$3" && ruff check --no-cache --config "$2/$1" ldd_setup_check.py) ;;
+    eslint.config.ldd.mjs) node --check "$2/$1" ;;
+    *)                     return 2 ;;
+  esac
+}
+
+lint_file_length_proposal() {
+  case "$1" in
+    go)                    printf "a setting to propose, never to add on your own: revive file-length-limit, as the plugin's setup/golangci.yaml sets it" ;;
+    typescript|javascript) printf "a setting to propose, never to add on your own: sonarjs/max-lines, as the plugin's setup/eslint.config.ldd.mjs sets it" ;;
+    python)                printf "ruff has no file-length rule, so this script holds the limit; a .ldd-lint.yaml entry file_max_lines: <n> states another" ;;
+    *)                     printf "no linter rule is known for %s; a .ldd-lint.yaml entry file_max_lines: <n> states another limit" "$1" ;;
+  esac
+}
+# ================== end linter table ==================
+
 # ========================= cases =========================
 run_row_cases() { # runs every case against the current row
 
@@ -300,7 +466,16 @@ finish
 begin "the plugin's default names a linter setting to propose, never to add"
 write_src "src/a$FX_EXT" 1
 run_lint file-length
-expect_exit 0 && expect_has "profile default ($MAX_LINES code lines)" && expect_has "a setting to propose, never to add on your own: " && ok
+SETUP_DIR="$(dirname "$LINT")/../setup"
+if [[ -n "$FX_SETUP_FILE" ]]; then
+  expect_exit 0 && expect_has "profile default ($MAX_LINES code lines)" \
+    && expect_has "a setting to propose, never to add on your own: " \
+    && expect_has "$FX_LENGTH_RULE, as the plugin's setup/$FX_SETUP_FILE sets it" \
+    && { grep -q -- "$FX_LENGTH_RULE" "$SETUP_DIR/$FX_SETUP_FILE" && grep -q -- "$MAX_LINES" "$SETUP_DIR/$FX_SETUP_FILE" || bad "setup/$FX_SETUP_FILE does not set $FX_LENGTH_RULE at $MAX_LINES"; } \
+    && grep -q -- "$FX_LENGTH_RULE" "$SETUP_DIR/$FX_SETUP_FILE" && ok
+else
+  expect_exit 0 && expect_has "profile default ($MAX_LINES code lines)" && expect_has "a .ldd-lint.yaml entry file_max_lines" && ok
+fi
 finish
 
 begin "a file-length rule in the linter config hands file length to the linter"
@@ -470,6 +645,18 @@ for opt in --root --files --glob --test-re; do
   finish
 done
 
+# --- the recommended configs under setup/, checked by their own linters when
+# the machine has them ---
+SETUP_DIR="$(dirname "$LINT")/../setup"
+
+while IFS=$'\t' read -r setup_file setup_tool; do
+  begin "setup/$setup_file passes its own linter's check"
+  if ! command -v "$setup_tool" >/dev/null 2>&1; then skip "$setup_tool is not on PATH"; finish; continue; fi
+  OUT=$(lint_setup_check "$setup_file" "$SETUP_DIR" "$REPO" 2>&1); CODE=$?; ERR=""
+  expect_exit 0 && ok
+  finish
+done < <(lint_setup_files)
+
 # ========================= summary =========================
 echo
 echo "ldd-lint_test: $pass passed, $failed failed, $skipped skipped"
diff --git a/linter-driven-development/scripts/ldd-scope_test.sh b/linter-driven-development/scripts/ldd-scope_test.sh
index fe40f58..9f21328 100755
--- a/linter-driven-development/scripts/ldd-scope_test.sh
+++ b/linter-driven-development/scripts/ldd-scope_test.sh
@@ -117,6 +117,9 @@ mk_repo() { fx_write_marker "$REPO" fixture; fx_write_code; mk_docs; }
 #   FX_BLOCK_OPEN      the line that opens a block comment, "" when the
 #   FX_BLOCK_CLOSE     language has none, and the line that closes it
 #   FX_SKIP_FILES      source file names a directory count leaves out
+#   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
+#                      the file-length limit, and FX_LENGTH_RULE its rule; both
+#                      "" when the language's linter has no file-length rule
 #   fx_test_file <dir> <n>             a test file's path in <dir>
 #   FX_LINTER_CONFIG   the path, under the repository root, of the file that
 #                      fx_write_linter_config writes, and FX_LINTER_COMMENT the
@@ -134,6 +137,8 @@ use_row() {
   case "$1" in
     go)
       FX_LINTER_CONFIG='.golangci.yml'
+      FX_SETUP_FILE='golangci.yaml'
+      FX_LENGTH_RULE='file-length-limit'
       FX_LINTER_COMMENT='#'
       FX_EXT='.go'
       FX_LINE_COMMENT='// note'
@@ -146,6 +151,8 @@ use_row() {
       ;;
     python)
       FX_LINTER_CONFIG='.pylintrc'
+      FX_SETUP_FILE=''
+      FX_LENGTH_RULE=''
       FX_LINTER_COMMENT=';'
       FX_EXT='.py'
       FX_LINE_COMMENT='# note'
diff --git a/linter-driven-development/setup/eslint.config.ldd.mjs b/linter-driven-development/setup/eslint.config.ldd.mjs
new file mode 100644
index 0000000..3e47c93
--- /dev/null
+++ b/linter-driven-development/setup/eslint.config.ldd.mjs
@@ -0,0 +1,93 @@
+// Recommended ESLint flat-config fragment of the linter-driven-development
+// plugins: every rule the plugin's routing table routes to one of the twelve
+// design rules, at the limits the rules name. Each rule line says which rule its
+// failures feed. The plugin never writes this file into a repository: the
+// repository's owners copy it, or the parts they want, beside eslint.config.js
+// and spread it into the exported array:
+//
+//   import ldd from './eslint.config.ldd.mjs'
+//   export default [...yourConfig, ...ldd]
+//
+// residue-exempt: an ESLint configuration names its plugins and rules on purpose.
+// It needs eslint-plugin-sonarjs, eslint-plugin-react, eslint-plugin-react-hooks,
+// eslint-plugin-promise, eslint-plugin-import and typescript-eslint; a repository
+// that does not use one of them leaves its rules out. Limits a repository already
+// sets stay the repository's: the linter is the authority for every threshold it
+// holds. Rules this file leaves out (style, imports, formatting) are the
+// repository's own choice.
+//
+// Adopt it on an existing codebase with ESLint's bulk suppressions: run
+// `npx eslint --suppress-all` once to record today's violations, so only new ones
+// fail; `npx eslint --prune-suppressions` drops the entries that are fixed.
+
+import importPlugin from 'eslint-plugin-import'
+import promise from 'eslint-plugin-promise'
+import react from 'eslint-plugin-react'
+import reactHooks from 'eslint-plugin-react-hooks'
+import sonarjs from 'eslint-plugin-sonarjs'
+import tseslint from 'typescript-eslint'
+
+export default [
+  {
+    files: ['**/*.{ts,tsx}'],
+    plugins: {
+      '@typescript-eslint': tseslint.plugin,
+      import: importPlugin,
+      promise,
+      react,
+      'react-hooks': reactHooks,
+      sonarjs,
+    },
+    rules: {
+      // R3 storifying
+      'sonarjs/cognitive-complexity': ['error', 15],
+      'sonarjs/cyclomatic-complexity': ['error', { threshold: 10 }],
+      'sonarjs/expression-complexity': ['error', { max: 5 }],
+      'sonarjs/max-lines-per-function': ['error', { maximum: 200 }],
+      'sonarjs/nested-control-flow': ['error', { maximumNestingLevel: 4 }],
+      'sonarjs/no-nested-conditional': 'error',
+      'sonarjs/no-nested-functions': 'error',
+      'sonarjs/elseif-without-else': 'error',
+      'react/no-unstable-nested-components': 'error',
+      // R1 primitive obsession
+      'max-params': ['error', 4],
+      'sonarjs/no-duplicate-string': ['error', { threshold: 3 }],
+      'sonarjs/max-union-size': ['error', { threshold: 4 }],
+      'sonarjs/no-identical-functions': 'error',
+      // R2 self-validating types: parse at the boundary
+      '@typescript-eslint/no-explicit-any': 'error',
+      '@typescript-eslint/no-non-null-assertion': 'error',
+      // R5 vertical slice: one juicy module per file; counts code lines only
+      'sonarjs/max-lines': ['error', { maximum: 450 }],
+      'react/no-multi-comp': ['error', { ignoreStateless: false }],
+      // R8 no globals
+      'import/no-mutable-exports': 'error',
+      // R10 concurrency safety
+      'react-hooks/exhaustive-deps': 'error',
+      '@typescript-eslint/no-floating-promises': 'error',
+      '@typescript-eslint/no-misused-promises': 'error',
+      'promise/catch-or-return': 'error',
+      // R11 conditional dispatch
+      '@typescript-eslint/switch-exhaustiveness-check': 'error',
+      'sonarjs/no-nested-switch': 'error',
+      'sonarjs/max-switch-cases': 'error',
+      'sonarjs/no-small-switch': 'error',
+      // R12 mutation discipline
+      'no-param-reassign': ['error', { props: true }],
+      'sonarjs/prefer-read-only-props': 'error',
+      'react/no-direct-mutation-state': 'error',
+    },
+  },
+  {
+    // Tests are long and repeat literals by design.
+    files: ['**/*.test.{ts,tsx}', '**/*.spec.{ts,tsx}'],
+    rules: {
+      'sonarjs/max-lines-per-function': 'off',
+      'sonarjs/no-duplicate-string': 'off',
+      'sonarjs/no-nested-functions': 'off',
+      'max-params': 'off',
+      'react/no-multi-comp': 'off',
+      '@typescript-eslint/no-non-null-assertion': 'off',
+    },
+  },
+]
diff --git a/linter-driven-development/setup/golangci.yaml b/linter-driven-development/setup/golangci.yaml
new file mode 100644
index 0000000..da5ef91
--- /dev/null
+++ b/linter-driven-development/setup/golangci.yaml
@@ -0,0 +1,82 @@
+# Recommended golangci-lint v2 configuration of the linter-driven-development
+# plugins: every linter rule the plugin's routing table routes to one of the
+# twelve design rules, at the limits the rules name. Each linter line says which
+# rule its failures feed. The plugin never writes this file into a repository:
+# the repository's owners copy it, or the parts they want, into .golangci.yaml.
+# residue-exempt: a golangci-lint configuration names its linters on purpose.
+#
+# Limits a repository already sets stay the repository's: the linter is the
+# authority for every threshold it holds. Rules this file leaves out (style,
+# naming, formatting) are the repository's own choice.
+#
+# Adopt it on an existing codebase with the ratchet below: only issues in code
+# changed since the merge base with main fail, so old code is not a wall of
+# findings on day one. Remove the ratchet once the old findings are gone.
+
+version: "2"
+
+issues:
+  new-from-merge-base: main
+
+linters:
+  default: none
+  enable:
+    - gocyclo           # R3 storifying: cyclomatic complexity
+    - gocognit          # R3 storifying: cognitive complexity
+    - funlen            # R3 storifying: function length
+    - nestif            # R3 storifying: nesting depth
+    - maintidx          # R3 storifying, R1 types: maintainability index
+    - dupl              # R1 types: duplicated logic; a duplicated switch is R11
+    - exhaustive        # R11 conditional dispatch: missing enum cases
+    - gochecknoglobals  # R8 no globals
+    - gochecknoinits    # R8 no globals
+    - ireturn           # R6 test-only interfaces: a constructor that returns an interface
+    - govet             # R10 concurrency: copylocks
+    - revive            # R1 types, R5 vertical slice: the rules below
+    - errcheck          # mechanical: an error that is not handled
+    - wrapcheck         # mechanical: an error without the context of its layer
+    - goconst           # mechanical; an enum-shaped string is R1's "Name enum strings"
+  settings:
+    gocyclo:
+      min-complexity: 10
+    gocognit:
+      min-complexity: 15
+    funlen:
+      lines: 50
+      statements: 40
+    nestif:
+      min-complexity: 2
+    maintidx:
+      under: 20
+    dupl:
+      threshold: 100
+    exhaustive:
+      # A default branch does not count as handling a case: every new case is
+      # handled where the switch is.
+      default-signifies-exhaustive: false
+    govet:
+      enable:
+        - copylocks
+    goconst:
+      min-len: 3
+      min-occurrences: 3
+    revive:
+      rules:
+        - name: argument-limit          # R1: more than 4 parameters wants a parameter object
+          arguments: [4]
+        - name: function-result-limit   # R1: more than 3 results wants a named result type
+          arguments: [3]
+        - name: file-length-limit       # R5: one juicy type per file; counts code lines only
+          arguments: [{max: 450, skip-comments: true, skip-blank-lines: true}]
+        - name: early-return            # mechanical: invert the condition and return early
+  exclusions:
+    rules:
+      # Tests are long and repeat literals by design.
+      - path: _test\.go
+        linters:
+          - funlen
+          - gocognit
+          - gocyclo
+          - maintidx
+          - dupl
+          - goconst
diff --git a/linter-driven-development/setup/ruff.toml b/linter-driven-development/setup/ruff.toml
new file mode 100644
index 0000000..36ce201
--- /dev/null
+++ b/linter-driven-development/setup/ruff.toml
@@ -0,0 +1,53 @@
+# Recommended ruff configuration of the linter-driven-development plugins:
+# every rule the plugin's routing table routes to one of the twelve design
+# rules, at the limits the rules name. Each rule says which rule its failures
+# feed. The plugin never writes this file into a repository: the repository's
+# owners copy it, or the parts they want, into ruff.toml, or into
+# pyproject.toml with each table name prefixed by "tool.ruff." ([lint] becomes
+# [tool.ruff.lint]).
+# residue-exempt: a ruff configuration names its rule codes on purpose.
+#
+# Limits a repository already sets stay the repository's: the linter is the
+# authority for every threshold it holds. Rules this file leaves out (style,
+# docstrings, imports) are the repository's own choice. ruff has no file-length
+# rule: the plugin's gap linter, scripts/ldd-lint.sh file-length, holds that
+# limit at 450 code lines.
+#
+# Adopt it on an existing codebase one change at a time: run ruff on the files
+# changed since the merge base with main, so old code is not a wall of
+# findings on day one:
+#   git diff --name-only --diff-filter=d "$(git merge-base HEAD main)" -- '*.py' | xargs ruff check
+
+[lint]
+# PLR1702 (nested blocks) is a preview rule.
+preview = true
+explicit-preview-rules = true
+extend-select = [
+  "C901",     # R3 storifying: complexity
+  "PLR0911",  # R3 storifying: too many returns
+  "PLR0912",  # R3 storifying: too many branches
+  "PLR0915",  # R3 storifying: too many statements
+  "PLR1702",  # R3 storifying: nesting
+  "PLR0913",  # R1 types: too many arguments wants a parameter object
+  "PLR2004",  # R1 types: a magic value; an enum-shaped string is "Name enum strings"
+  "FBT001",   # R11 conditional dispatch: a boolean positional parameter
+  "FBT002",   # R11 conditional dispatch: a boolean default parameter
+  "PLW0603",  # R8 no globals: a global statement
+  "B006",     # R12 mutation discipline: a mutable default argument
+  "B008",     # R12 mutation discipline: a call in a default argument
+]
+
+[lint.mccabe]
+max-complexity = 8
+
+[lint.pylint]
+max-args = 4          # self and cls are not counted
+max-branches = 12
+max-returns = 6
+max-statements = 50
+max-nested-blocks = 5
+
+[lint.per-file-ignores]
+# Tests repeat literals and take many fixtures by design.
+"**/test_*.py" = ["PLR2004", "PLR0913", "FBT001", "FBT002"]
+"**/*_test.py" = ["PLR2004", "PLR0913", "FBT001", "FBT002"]
diff --git a/python-linter-driven-development/CHANGELOG.md b/python-linter-driven-development/CHANGELOG.md
index 380c0df..1d8d852 100644
--- a/python-linter-driven-development/CHANGELOG.md
+++ b/python-linter-driven-development/CHANGELOG.md
@@ -7,6 +7,15 @@ Format based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); versio
 
 ### Added
 
+- **A recommended linter setup.** `setup/golangci.yaml`, `setup/ruff.toml` and
+  `setup/eslint.config.ldd.mjs` enable every linter rule the routing table routes to
+  a design rule, at the limits the rules name, with a way to adopt each on an
+  existing codebase: golangci-lint's merge-base ratchet, ESLint's bulk
+  suppressions, and ruff on changed files. The plugin never writes them into a
+  repository. The gap linter's threshold line names the file and rule that would
+  hold a file-length limit; for Python, where ruff has no file-length rule, it says
+  that the gap linter holds it.
+
 - **A gap linter for the design triggers no linter holds.** `scripts/ldd-lint.sh`
   measures lines per source file (`file-length`) and source files per directory
   (`package-size`). Where the repository's linter config names a file-length rule,
@@ -27,6 +36,10 @@ Format based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); versio
 
 ### Fixed
 
+- **The gap linter runs under bash 3.2.** macOS's `/bin/bash` stopped
+  `ldd-lint.sh` with a syntax error: bash 3.2 misreads a `case` pattern inside a
+  process substitution. The script now runs under bash 3.2 and bash 5.
+
 - **A value-taking option given last no longer hangs the review scripts.** When
   `ldd-detect.sh` or `ldd-scope.sh` got an option such as `--root` or `--base` as
   its last argument, the script looped forever. It now stops with "<option> needs
diff --git a/python-linter-driven-development/README.md b/python-linter-driven-development/README.md
index 762721b..5c3af42 100644
--- a/python-linter-driven-development/README.md
+++ b/python-linter-driven-development/README.md
@@ -98,9 +98,15 @@ checker the repository does not use.
   `PLR0913` to R1, `PLW0603` to R8, `FBT` to R11, `B006`/`B008` to R12. The
   mechanical row — `ARG`, `SIM`, `RET`, `B904`, `BLE001`, `PLR2004`, import order,
   style — is fixed by the lint-fixer in an isolated context.
-- **Some findings have no ruff rule.** Duplicated code, file length, a `match`
-  missing enum cases, a `Protocol` with one implementer and shared-state races are
-  review findings: the hunters own them alone.
+- **Some findings have no ruff rule.** Duplicated code, a `match` missing enum
+  cases, a `Protocol` with one implementer and shared-state races are review
+  findings: the hunters own them alone. File length has no ruff rule either: the
+  gap linter, `scripts/ldd-lint.sh file-length`, measures it.
+- **The recommended setup makes the design triggers fire.** `setup/ruff.toml` in the
+  plugin directory selects every ruff rule the routing table routes to a design
+  rule, at the limits the rules name. The plugin never writes it into your
+  repository: copy it, or the parts you want, into `ruff.toml` or `pyproject.toml`.
+  Limits your configuration already sets stay yours.
 - **`# noqa`, `# ty: ignore` and `# type: ignore` are all suppressions.** The lint-fixer
   never adds one and never edits `[tool.ruff]`, `[tool.ty]` or `[tool.mypy]`; a new
   one in a diff is itself a review finding.
diff --git a/python-linter-driven-development/scripts/ldd-detect_test.sh b/python-linter-driven-development/scripts/ldd-detect_test.sh
index 941acf9..6921c09 100644
--- a/python-linter-driven-development/scripts/ldd-detect_test.sh
+++ b/python-linter-driven-development/scripts/ldd-detect_test.sh
@@ -141,6 +141,9 @@ questions_in_rules() {
 #   FX_BLOCK_OPEN      the line that opens a block comment, "" when the
 #   FX_BLOCK_CLOSE     language has none, and the line that closes it
 #   FX_SKIP_FILES      source file names a directory count leaves out
+#   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
+#                      the file-length limit, and FX_LENGTH_RULE its rule; both
+#                      "" when the language's linter has no file-length rule
 #   fx_test_file <dir> <n>             a test file's path in <dir>
 #   FX_LINTER_CONFIG   the path, under the repository root, of the file that
 #                      fx_write_linter_config writes, and FX_LINTER_COMMENT the
@@ -156,6 +159,8 @@ FX_NATIVE="python"
 
 use_row() {
   FX_LINTER_CONFIG='pyproject.toml'
+  FX_SETUP_FILE=''
+  FX_LENGTH_RULE=''
   FX_LINTER_COMMENT='#'
   FX_EXT='.py'
   FX_LINE_COMMENT='# note'
diff --git a/python-linter-driven-development/scripts/ldd-lint.sh b/python-linter-driven-development/scripts/ldd-lint.sh
index 4fa1f97..4ca2b89 100755
--- a/python-linter-driven-development/scripts/ldd-lint.sh
+++ b/python-linter-driven-development/scripts/ldd-lint.sh
@@ -225,9 +225,15 @@ lang_is_test() {
 #                                   nothing. A named rule belongs to the linter:
 #                                   its limit, its counting and whether it is on
 #                                   are the repository's decision.
-#   lint_file_length_snippet <id> <max>  the linter setting that would hold the
-#                                   limit, or the .ldd-lint.yaml entry when no
-#                                   linter rule is known: text to propose
+#   lint_setup_files                one line per recommended config under the
+#                                   plugin's setup/: file TAB the tool that checks it
+#   lint_setup_check <file> <setup dir> <work dir>  run that tool's own check of
+#                                   the file; exit 0 when the tool accepts it
+#   lint_file_length_proposal <id>  what would hold the limit in the
+#                                   repository's linter: the rule, named after
+#                                   the plugin's recommended config under setup/
+#                                   that sets it, or the .ldd-lint.yaml entry when
+#                                   the language's linter has no such rule
 
 lint_comment_style() {
   case "$1" in
@@ -330,12 +336,27 @@ lint_file_length_rule() {
   return 0
 }
 
-lint_file_length_snippet() {
+lint_setup_files() {
+  printf 'golangci.yaml\tgolangci-lint\n'
+  printf 'ruff.toml\truff\n'
+  printf 'eslint.config.ldd.mjs\tnode\n'
+}
+
+lint_setup_check() { # <file> <setup dir> <work dir>
+  case "$1" in
+    golangci.yaml)         golangci-lint config verify -c "$2/$1" ;;
+    ruff.toml)             printf 'x = 1\n' > "$3/ldd_setup_check.py" && (cd "$3" && ruff check --no-cache --config "$2/$1" ldd_setup_check.py) ;;
+    eslint.config.ldd.mjs) node --check "$2/$1" ;;
+    *)                     return 2 ;;
+  esac
+}
+
+lint_file_length_proposal() {
   case "$1" in
-    go)                    printf "revive in .golangci.yaml: - name: file-length-limit, arguments: [{max: %s, skip-comments: true, skip-blank-lines: true}]" "$2" ;;
-    typescript|javascript) printf "the eslint config: 'sonarjs/max-lines': ['error', { maximum: %s }]" "$2" ;;
-    python)                printf "pyproject.toml: [tool.pylint.format] max-module-lines = %s (pylint counts every line, comments and blank lines too)" "$2" ;;
-    *)                     printf "no linter rule is known for %s; a .ldd-lint.yaml entry file_max_lines: %s would state this limit" "$1" "$2" ;;
+    go)                    printf "a setting to propose, never to add on your own: revive file-length-limit, as the plugin's setup/golangci.yaml sets it" ;;
+    typescript|javascript) printf "a setting to propose, never to add on your own: sonarjs/max-lines, as the plugin's setup/eslint.config.ldd.mjs sets it" ;;
+    python)                printf "ruff has no file-length rule, so this script holds the limit; a .ldd-lint.yaml entry file_max_lines: <n> states another" ;;
+    *)                     printf "no linter rule is known for %s; a .ldd-lint.yaml entry file_max_lines: <n> states another limit" "$1" ;;
   esac
 }
 # ================== end linter table ==================
@@ -407,6 +428,16 @@ trap 'rm -f "$SCOPE" "$INVENTORY"' EXIT
 list_candidates | by_language > "$SCOPE"
 if [[ -n "$FILES_LIST" ]]; then list_repo | by_language > "$INVENTORY"; else cp "$SCOPE" "$INVENTORY"; fi
 
+# dir_of <path> — the directory part of a relative path, "." for a file at
+# the root. A function, because bash 3.2 misreads a case pattern's ")" inside
+# a process substitution.
+dir_of() {
+  case "$1" in
+    */*) printf '%s\n' "${1%/*}" ;;
+    *)   printf '.\n' ;;
+  esac
+}
+
 # measured <path> — exit 0 when the file counts for this language: not under
 # an excluded directory, not a test, not generated. Every path the script
 # hands to find, head or awk starts with "./", and a directory is cut from a
@@ -438,7 +469,7 @@ run_file_length() { # <id> — every measured file of that language
     say "threshold: $id file length — set by $OVERRIDE_FILE ($max code lines)"
   else
     max="$DEFAULT_FILE_MAX_LINES"; src="profile default"
-    say "threshold: $id file length — profile default ($max code lines); the repository's linter does not hold it; a setting to propose, never to add on your own: $(lint_file_length_snippet "$id" "$max")"
+    say "threshold: $id file length — profile default ($max code lines); the repository's linter does not hold it; $(lint_file_length_proposal "$id")"
   fi
   while IFS=$'\t' read -r _ f; do
     measured "$f" || continue
@@ -462,7 +493,7 @@ run_package_size() { # <id> — every directory that holds a measured file of th
   awk -F'\t' -v id="$id" '$1 == id { print $2 }' "$INVENTORY" | while IFS= read -r f; do
     [[ -n "$skip" ]] && printf '%s\n' "$f" | grep -qE -- "$skip" && continue
     measured "$f" || continue
-    case "$f" in */*) printf '%s\n' "${f%/*}" ;; *) printf '.\n' ;; esac
+    dir_of "$f"
   done | LC_ALL=C sort | uniq -c | awk '{ n = $1; sub(/^[ \t]*[0-9]+[ \t]/, ""); print $0 "\t" n }' > "$counts"
   while IFS= read -r d; do
     n=$(awk -F'\t' -v d="$d" '$1 == d { print $2; exit }' "$counts")
@@ -473,8 +504,7 @@ run_package_size() { # <id> — every directory that holds a measured file of th
       finding "$d" "$n source files (warning at $warn, $src)"
     fi
   done < <(awk -F'\t' -v id="$id" '$1 == id { print $2 }' "$SCOPE" | while IFS= read -r f; do
-             measured "$f" || continue
-             case "$f" in */*) printf '%s\n' "${f%/*}" ;; *) printf '.\n' ;; esac
+             measured "$f" && dir_of "$f"
            done | LC_ALL=C sort -u)
   rm -f "$counts"
 }
diff --git a/python-linter-driven-development/scripts/ldd-lint_test.sh b/python-linter-driven-development/scripts/ldd-lint_test.sh
index 2289c66..6093bb0 100644
--- a/python-linter-driven-development/scripts/ldd-lint_test.sh
+++ b/python-linter-driven-development/scripts/ldd-lint_test.sh
@@ -105,6 +105,9 @@ fill_dir() {
 #   FX_BLOCK_OPEN      the line that opens a block comment, "" when the
 #   FX_BLOCK_CLOSE     language has none, and the line that closes it
 #   FX_SKIP_FILES      source file names a directory count leaves out
+#   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
+#                      the file-length limit, and FX_LENGTH_RULE its rule; both
+#                      "" when the language's linter has no file-length rule
 #   fx_test_file <dir> <n>             a test file's path in <dir>
 #   FX_LINTER_CONFIG   the path, under the repository root, of the file that
 #                      fx_write_linter_config writes, and FX_LINTER_COMMENT the
@@ -120,6 +123,8 @@ FX_NATIVE="python"
 
 use_row() {
   FX_LINTER_CONFIG='pyproject.toml'
+  FX_SETUP_FILE=''
+  FX_LENGTH_RULE=''
   FX_LINTER_COMMENT='#'
   FX_EXT='.py'
   FX_LINE_COMMENT='# note'
@@ -174,6 +179,165 @@ fx_write_linter_config_other() {
   printf '[tool.pylint.design]\nmax-args = 4\n' > "$REPO/pyproject.toml"
 }
 
+# ==================== linter table ====================
+# What the gap linter needs to know per language id: how a comment is written,
+# which source files a directory count leaves out, and whether the
+# repository's own linter holds the file-length limit. The same table is
+# rendered into every plugin, so two plugins measure one file the same way.
+# residue-exempt: the table names every language's linter and config file on
+# purpose, the same in every rendering.
+#
+#   lint_comment_style <id>         c (// and /* */), d (also /+ +/) or hash (#)
+#   lint_strip_comments <style> <file>  the file with every comment removed and
+#                                   string literals kept, one output line per
+#                                   input line: a comment-only line prints empty.
+#                                   Styles: c, d, hash (# and triple-quoted
+#                                   strings), ini (# and a leading ;)
+#   lint_package_skip_re <id>       ERE over a relative path: source files a
+#                                   directory count leaves out (an index module,
+#                                   a package marker, generated stubs); "" for none
+#   lint_file_length_rule <id>      "<rule> in <config file>" when a linter config
+#                                   at the repository root names a file-length
+#                                   rule outside a comment, else
+#                                   nothing. A named rule belongs to the linter:
+#                                   its limit, its counting and whether it is on
+#                                   are the repository's decision.
+#   lint_setup_files                one line per recommended config under the
+#                                   plugin's setup/: file TAB the tool that checks it
+#   lint_setup_check <file> <setup dir> <work dir>  run that tool's own check of
+#                                   the file; exit 0 when the tool accepts it
+#   lint_file_length_proposal <id>  what would hold the limit in the
+#                                   repository's linter: the rule, named after
+#                                   the plugin's recommended config under setup/
+#                                   that sets it, or the .ldd-lint.yaml entry when
+#                                   the language's linter has no such rule
+
+lint_comment_style() {
+  case "$1" in
+    python|ruby|shell) printf 'hash' ;;
+    d)                 printf 'd' ;;
+    *)                 printf 'c' ;;
+  esac
+}
+
+lint_package_skip_re() {
+  case "$1" in
+    go)                    printf '%s' '(_gen|\.pb)\.go$' ;;
+    python)                printf '%s' '(^|/)(__init__|conftest)\.py$|_pb2(_grpc)?\.py$' ;;
+    typescript|javascript) printf '%s' '(^|/)index\.[cm]?[jt]sx?$|\.stories\.[cm]?[jt]sx?$' ;;
+  esac
+  return 0
+}
+
+# LINT_STRIP_AWK walks each line one character at a time. A quote opens a
+# string that a comment marker cannot end; single and double quotes close at
+# the end of the line, a backtick string (c and d) and a triple-quoted string
+# (hash) run on. A block comment may open after code and run on. The awk uses
+# substr and string compares only, so mawk, gawk and BSD awk read it alike.
+LINT_STRIP_AWK='
+BEGIN { bq = sprintf("%c", 96); sq = sprintf("%c", 39); dq = "\"" }
+{
+  line = $0; out = ""; n = length(line); i = 1
+  if (q == dq || q == sq) q = ""
+  while (i <= n) {
+    if (inblock) {
+      if (substr(line, i, length(closer)) == closer) { inblock = 0; i += length(closer); out = out " "; continue }
+      i++; continue
+    }
+    ch = substr(line, i, 1)
+    if (q != "") {
+      if (ch == "\\" && (q == dq || q == sq)) { out = out substr(line, i, 2); i += 2; continue }
+      if (substr(line, i, length(q)) == q) { out = out q; i += length(q); q = ""; continue }
+      out = out ch; i++; continue
+    }
+    if (style == "hash" || style == "ini") {
+      if (ch == "#") break
+      if (style == "ini" && ch == ";" && out ~ /^[ \t]*$/) break
+      three = substr(line, i, 3)
+      if (style == "hash" && (three == dq dq dq || three == sq sq sq)) { q = three; out = out three; i += 3; continue }
+    } else {
+      two = substr(line, i, 2)
+      if (two == "//") break
+      if (two == "/*" || (style == "d" && two == "/+")) { inblock = 1; closer = (two == "/+") ? "+/" : "*/"; out = out " "; i += 2; continue }
+      if (ch == bq) { q = bq; out = out ch; i++; continue }
+    }
+    if (ch == dq || ch == sq) { q = ch; out = out ch; i++; continue }
+    out = out ch; i++
+  }
+  print out
+}
+'
+
+lint_strip_comments() { # <style> <file>
+  awk -v style="$1" "$LINT_STRIP_AWK" "$2"
+}
+
+# _lint_config_style <config file> — how that config format writes a comment
+_lint_config_style() {
+  case "$1" in
+    *.yaml|*.yml|*.toml) printf 'hash' ;;
+    *.cfg|*.ini|.pylintrc|pylintrc) printf 'ini' ;;
+    *) printf 'c' ;;
+  esac
+}
+
+# _lint_names <ERE> <file>... — print the first file whose text outside its
+# comments matches the pattern
+_lint_names() {
+  local re="$1" f; shift
+  for f in "$@"; do
+    [[ -f "$f" ]] || continue
+    lint_strip_comments "$(_lint_config_style "$f")" "./$f" 2>/dev/null | grep -qE -- "$re" && { printf '%s' "$f"; return 0; }
+  done
+  return 1
+}
+
+lint_file_length_rule() {
+  local f
+  case "$1" in
+    go)
+      f=$(_lint_names 'file-length-limit' .golangci.yaml .golangci.yml .golangci.toml .golangci.json) \
+        && printf 'revive file-length-limit in %s' "$f" ;;
+    typescript|javascript)
+      local configs=(eslint.config.js eslint.config.mjs eslint.config.cjs eslint.config.ts eslint.config.mts eslint.config.cts
+                     .eslintrc .eslintrc.js .eslintrc.cjs .eslintrc.json .eslintrc.yml .eslintrc.yaml)
+      if f=$(_lint_names 'sonarjs/max-lines([^-a-zA-Z]|$)' "${configs[@]}"); then
+        printf 'sonarjs/max-lines in %s' "$f"
+      elif f=$(_lint_names '(^|[^-/a-zA-Z])max-lines([^-a-zA-Z]|$)' "${configs[@]}"); then
+        printf 'max-lines in %s' "$f"
+      fi ;;
+    python)
+      f=$(_lint_names '^[[:space:]]*max-module-lines[[:space:]]*=' pyproject.toml .pylintrc pylintrc setup.cfg tox.ini) \
+        && printf 'pylint max-module-lines in %s' "$f" ;;
+  esac
+  return 0
+}
+
+lint_setup_files() {
+  printf 'golangci.yaml\tgolangci-lint\n'
+  printf 'ruff.toml\truff\n'
+  printf 'eslint.config.ldd.mjs\tnode\n'
+}
+
+lint_setup_check() { # <file> <setup dir> <work dir>
+  case "$1" in
+    golangci.yaml)         golangci-lint config verify -c "$2/$1" ;;
+    ruff.toml)             printf 'x = 1\n' > "$3/ldd_setup_check.py" && (cd "$3" && ruff check --no-cache --config "$2/$1" ldd_setup_check.py) ;;
+    eslint.config.ldd.mjs) node --check "$2/$1" ;;
+    *)                     return 2 ;;
+  esac
+}
+
+lint_file_length_proposal() {
+  case "$1" in
+    go)                    printf "a setting to propose, never to add on your own: revive file-length-limit, as the plugin's setup/golangci.yaml sets it" ;;
+    typescript|javascript) printf "a setting to propose, never to add on your own: sonarjs/max-lines, as the plugin's setup/eslint.config.ldd.mjs sets it" ;;
+    python)                printf "ruff has no file-length rule, so this script holds the limit; a .ldd-lint.yaml entry file_max_lines: <n> states another" ;;
+    *)                     printf "no linter rule is known for %s; a .ldd-lint.yaml entry file_max_lines: <n> states another limit" "$1" ;;
+  esac
+}
+# ================== end linter table ==================
+
 # ========================= cases =========================
 run_row_cases() { # runs every case against the current row
 
@@ -233,7 +397,16 @@ finish
 begin "the plugin's default names a linter setting to propose, never to add"
 write_src "src/a$FX_EXT" 1
 run_lint file-length
-expect_exit 0 && expect_has "profile default ($MAX_LINES code lines)" && expect_has "a setting to propose, never to add on your own: " && ok
+SETUP_DIR="$(dirname "$LINT")/../setup"
+if [[ -n "$FX_SETUP_FILE" ]]; then
+  expect_exit 0 && expect_has "profile default ($MAX_LINES code lines)" \
+    && expect_has "a setting to propose, never to add on your own: " \
+    && expect_has "$FX_LENGTH_RULE, as the plugin's setup/$FX_SETUP_FILE sets it" \
+    && { grep -q -- "$FX_LENGTH_RULE" "$SETUP_DIR/$FX_SETUP_FILE" && grep -q -- "$MAX_LINES" "$SETUP_DIR/$FX_SETUP_FILE" || bad "setup/$FX_SETUP_FILE does not set $FX_LENGTH_RULE at $MAX_LINES"; } \
+    && grep -q -- "$FX_LENGTH_RULE" "$SETUP_DIR/$FX_SETUP_FILE" && ok
+else
+  expect_exit 0 && expect_has "profile default ($MAX_LINES code lines)" && expect_has "a .ldd-lint.yaml entry file_max_lines" && ok
+fi
 finish
 
 begin "a file-length rule in the linter config hands file length to the linter"
@@ -403,6 +576,18 @@ for opt in --root --files --glob --test-re; do
   finish
 done
 
+# --- the recommended configs under setup/, checked by their own linters when
+# the machine has them ---
+SETUP_DIR="$(dirname "$LINT")/../setup"
+
+while IFS=$'\t' read -r setup_file setup_tool; do
+  begin "setup/$setup_file passes its own linter's check"
+  if ! command -v "$setup_tool" >/dev/null 2>&1; then skip "$setup_tool is not on PATH"; finish; continue; fi
+  OUT=$(lint_setup_check "$setup_file" "$SETUP_DIR" "$REPO" 2>&1); CODE=$?; ERR=""
+  expect_exit 0 && ok
+  finish
+done < <(lint_setup_files)
+
 # ========================= summary =========================
 echo
 echo "ldd-lint_test: $pass passed, $failed failed, $skipped skipped"
diff --git a/python-linter-driven-development/scripts/ldd-scope_test.sh b/python-linter-driven-development/scripts/ldd-scope_test.sh
index c3c837f..4a805ca 100755
--- a/python-linter-driven-development/scripts/ldd-scope_test.sh
+++ b/python-linter-driven-development/scripts/ldd-scope_test.sh
@@ -117,6 +117,9 @@ mk_repo() { fx_write_marker "$REPO" fixture; fx_write_code; mk_docs; }
 #   FX_BLOCK_OPEN      the line that opens a block comment, "" when the
 #   FX_BLOCK_CLOSE     language has none, and the line that closes it
 #   FX_SKIP_FILES      source file names a directory count leaves out
+#   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
+#                      the file-length limit, and FX_LENGTH_RULE its rule; both
+#                      "" when the language's linter has no file-length rule
 #   fx_test_file <dir> <n>             a test file's path in <dir>
 #   FX_LINTER_CONFIG   the path, under the repository root, of the file that
 #                      fx_write_linter_config writes, and FX_LINTER_COMMENT the
@@ -132,6 +135,8 @@ FX_NATIVE="python"
 
 use_row() {
   FX_LINTER_CONFIG='pyproject.toml'
+  FX_SETUP_FILE=''
+  FX_LENGTH_RULE=''
   FX_LINTER_COMMENT='#'
   FX_EXT='.py'
   FX_LINE_COMMENT='# note'
diff --git a/python-linter-driven-development/setup/eslint.config.ldd.mjs b/python-linter-driven-development/setup/eslint.config.ldd.mjs
new file mode 100644
index 0000000..3e47c93
--- /dev/null
+++ b/python-linter-driven-development/setup/eslint.config.ldd.mjs
@@ -0,0 +1,93 @@
+// Recommended ESLint flat-config fragment of the linter-driven-development
+// plugins: every rule the plugin's routing table routes to one of the twelve
+// design rules, at the limits the rules name. Each rule line says which rule its
+// failures feed. The plugin never writes this file into a repository: the
+// repository's owners copy it, or the parts they want, beside eslint.config.js
+// and spread it into the exported array:
+//
+//   import ldd from './eslint.config.ldd.mjs'
+//   export default [...yourConfig, ...ldd]
+//
+// residue-exempt: an ESLint configuration names its plugins and rules on purpose.
+// It needs eslint-plugin-sonarjs, eslint-plugin-react, eslint-plugin-react-hooks,
+// eslint-plugin-promise, eslint-plugin-import and typescript-eslint; a repository
+// that does not use one of them leaves its rules out. Limits a repository already
+// sets stay the repository's: the linter is the authority for every threshold it
+// holds. Rules this file leaves out (style, imports, formatting) are the
+// repository's own choice.
+//
+// Adopt it on an existing codebase with ESLint's bulk suppressions: run
+// `npx eslint --suppress-all` once to record today's violations, so only new ones
+// fail; `npx eslint --prune-suppressions` drops the entries that are fixed.
+
+import importPlugin from 'eslint-plugin-import'
+import promise from 'eslint-plugin-promise'
+import react from 'eslint-plugin-react'
+import reactHooks from 'eslint-plugin-react-hooks'
+import sonarjs from 'eslint-plugin-sonarjs'
+import tseslint from 'typescript-eslint'
+
+export default [
+  {
+    files: ['**/*.{ts,tsx}'],
+    plugins: {
+      '@typescript-eslint': tseslint.plugin,
+      import: importPlugin,
+      promise,
+      react,
+      'react-hooks': reactHooks,
+      sonarjs,
+    },
+    rules: {
+      // R3 storifying
+      'sonarjs/cognitive-complexity': ['error', 15],
+      'sonarjs/cyclomatic-complexity': ['error', { threshold: 10 }],
+      'sonarjs/expression-complexity': ['error', { max: 5 }],
+      'sonarjs/max-lines-per-function': ['error', { maximum: 200 }],
+      'sonarjs/nested-control-flow': ['error', { maximumNestingLevel: 4 }],
+      'sonarjs/no-nested-conditional': 'error',
+      'sonarjs/no-nested-functions': 'error',
+      'sonarjs/elseif-without-else': 'error',
+      'react/no-unstable-nested-components': 'error',
+      // R1 primitive obsession
+      'max-params': ['error', 4],
+      'sonarjs/no-duplicate-string': ['error', { threshold: 3 }],
+      'sonarjs/max-union-size': ['error', { threshold: 4 }],
+      'sonarjs/no-identical-functions': 'error',
+      // R2 self-validating types: parse at the boundary
+      '@typescript-eslint/no-explicit-any': 'error',
+      '@typescript-eslint/no-non-null-assertion': 'error',
+      // R5 vertical slice: one juicy module per file; counts code lines only
+      'sonarjs/max-lines': ['error', { maximum: 450 }],
+      'react/no-multi-comp': ['error', { ignoreStateless: false }],
+      // R8 no globals
+      'import/no-mutable-exports': 'error',
+      // R10 concurrency safety
+      'react-hooks/exhaustive-deps': 'error',
+      '@typescript-eslint/no-floating-promises': 'error',
+      '@typescript-eslint/no-misused-promises': 'error',
+      'promise/catch-or-return': 'error',
+      // R11 conditional dispatch
+      '@typescript-eslint/switch-exhaustiveness-check': 'error',
+      'sonarjs/no-nested-switch': 'error',
+      'sonarjs/max-switch-cases': 'error',
+      'sonarjs/no-small-switch': 'error',
+      // R12 mutation discipline
+      'no-param-reassign': ['error', { props: true }],
+      'sonarjs/prefer-read-only-props': 'error',
+      'react/no-direct-mutation-state': 'error',
+    },
+  },
+  {
+    // Tests are long and repeat literals by design.
+    files: ['**/*.test.{ts,tsx}', '**/*.spec.{ts,tsx}'],
+    rules: {
+      'sonarjs/max-lines-per-function': 'off',
+      'sonarjs/no-duplicate-string': 'off',
+      'sonarjs/no-nested-functions': 'off',
+      'max-params': 'off',
+      'react/no-multi-comp': 'off',
+      '@typescript-eslint/no-non-null-assertion': 'off',
+    },
+  },
+]
diff --git a/python-linter-driven-development/setup/golangci.yaml b/python-linter-driven-development/setup/golangci.yaml
new file mode 100644
index 0000000..da5ef91
--- /dev/null
+++ b/python-linter-driven-development/setup/golangci.yaml
@@ -0,0 +1,82 @@
+# Recommended golangci-lint v2 configuration of the linter-driven-development
+# plugins: every linter rule the plugin's routing table routes to one of the
+# twelve design rules, at the limits the rules name. Each linter line says which
+# rule its failures feed. The plugin never writes this file into a repository:
+# the repository's owners copy it, or the parts they want, into .golangci.yaml.
+# residue-exempt: a golangci-lint configuration names its linters on purpose.
+#
+# Limits a repository already sets stay the repository's: the linter is the
+# authority for every threshold it holds. Rules this file leaves out (style,
+# naming, formatting) are the repository's own choice.
+#
+# Adopt it on an existing codebase with the ratchet below: only issues in code
+# changed since the merge base with main fail, so old code is not a wall of
+# findings on day one. Remove the ratchet once the old findings are gone.
+
+version: "2"
+
+issues:
+  new-from-merge-base: main
+
+linters:
+  default: none
+  enable:
+    - gocyclo           # R3 storifying: cyclomatic complexity
+    - gocognit          # R3 storifying: cognitive complexity
+    - funlen            # R3 storifying: function length
+    - nestif            # R3 storifying: nesting depth
+    - maintidx          # R3 storifying, R1 types: maintainability index
+    - dupl              # R1 types: duplicated logic; a duplicated switch is R11
+    - exhaustive        # R11 conditional dispatch: missing enum cases
+    - gochecknoglobals  # R8 no globals
+    - gochecknoinits    # R8 no globals
+    - ireturn           # R6 test-only interfaces: a constructor that returns an interface
+    - govet             # R10 concurrency: copylocks
+    - revive            # R1 types, R5 vertical slice: the rules below
+    - errcheck          # mechanical: an error that is not handled
+    - wrapcheck         # mechanical: an error without the context of its layer
+    - goconst           # mechanical; an enum-shaped string is R1's "Name enum strings"
+  settings:
+    gocyclo:
+      min-complexity: 10
+    gocognit:
+      min-complexity: 15
+    funlen:
+      lines: 50
+      statements: 40
+    nestif:
+      min-complexity: 2
+    maintidx:
+      under: 20
+    dupl:
+      threshold: 100
+    exhaustive:
+      # A default branch does not count as handling a case: every new case is
+      # handled where the switch is.
+      default-signifies-exhaustive: false
+    govet:
+      enable:
+        - copylocks
+    goconst:
+      min-len: 3
+      min-occurrences: 3
+    revive:
+      rules:
+        - name: argument-limit          # R1: more than 4 parameters wants a parameter object
+          arguments: [4]
+        - name: function-result-limit   # R1: more than 3 results wants a named result type
+          arguments: [3]
+        - name: file-length-limit       # R5: one juicy type per file; counts code lines only
+          arguments: [{max: 450, skip-comments: true, skip-blank-lines: true}]
+        - name: early-return            # mechanical: invert the condition and return early
+  exclusions:
+    rules:
+      # Tests are long and repeat literals by design.
+      - path: _test\.go
+        linters:
+          - funlen
+          - gocognit
+          - gocyclo
+          - maintidx
+          - dupl
+          - goconst
diff --git a/python-linter-driven-development/setup/ruff.toml b/python-linter-driven-development/setup/ruff.toml
new file mode 100644
index 0000000..36ce201
--- /dev/null
+++ b/python-linter-driven-development/setup/ruff.toml
@@ -0,0 +1,53 @@
+# Recommended ruff configuration of the linter-driven-development plugins:
+# every rule the plugin's routing table routes to one of the twelve design
+# rules, at the limits the rules name. Each rule says which rule its failures
+# feed. The plugin never writes this file into a repository: the repository's
+# owners copy it, or the parts they want, into ruff.toml, or into
+# pyproject.toml with each table name prefixed by "tool.ruff." ([lint] becomes
+# [tool.ruff.lint]).
+# residue-exempt: a ruff configuration names its rule codes on purpose.
+#
+# Limits a repository already sets stay the repository's: the linter is the
+# authority for every threshold it holds. Rules this file leaves out (style,
+# docstrings, imports) are the repository's own choice. ruff has no file-length
+# rule: the plugin's gap linter, scripts/ldd-lint.sh file-length, holds that
+# limit at 450 code lines.
+#
+# Adopt it on an existing codebase one change at a time: run ruff on the files
+# changed since the merge base with main, so old code is not a wall of
+# findings on day one:
+#   git diff --name-only --diff-filter=d "$(git merge-base HEAD main)" -- '*.py' | xargs ruff check
+
+[lint]
+# PLR1702 (nested blocks) is a preview rule.
+preview = true
+explicit-preview-rules = true
+extend-select = [
+  "C901",     # R3 storifying: complexity
+  "PLR0911",  # R3 storifying: too many returns
+  "PLR0912",  # R3 storifying: too many branches
+  "PLR0915",  # R3 storifying: too many statements
+  "PLR1702",  # R3 storifying: nesting
+  "PLR0913",  # R1 types: too many arguments wants a parameter object
+  "PLR2004",  # R1 types: a magic value; an enum-shaped string is "Name enum strings"
+  "FBT001",   # R11 conditional dispatch: a boolean positional parameter
+  "FBT002",   # R11 conditional dispatch: a boolean default parameter
+  "PLW0603",  # R8 no globals: a global statement
+  "B006",     # R12 mutation discipline: a mutable default argument
+  "B008",     # R12 mutation discipline: a call in a default argument
+]
+
+[lint.mccabe]
+max-complexity = 8
+
+[lint.pylint]
+max-args = 4          # self and cls are not counted
+max-branches = 12
+max-returns = 6
+max-statements = 50
+max-nested-blocks = 5
+
+[lint.per-file-ignores]
+# Tests repeat literals and take many fixtures by design.
+"**/test_*.py" = ["PLR2004", "PLR0913", "FBT001", "FBT002"]
+"**/*_test.py" = ["PLR2004", "PLR0913", "FBT001", "FBT002"]
diff --git a/ts-react-linter-driven-development/CHANGELOG.md b/ts-react-linter-driven-development/CHANGELOG.md
index d4d78ed..a452a3a 100644
--- a/ts-react-linter-driven-development/CHANGELOG.md
+++ b/ts-react-linter-driven-development/CHANGELOG.md
@@ -7,6 +7,15 @@ Format based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); versio
 
 ### Added
 
+- **A recommended linter setup.** `setup/golangci.yaml`, `setup/ruff.toml` and
+  `setup/eslint.config.ldd.mjs` enable every linter rule the routing table routes to
+  a design rule, at the limits the rules name, with a way to adopt each on an
+  existing codebase: golangci-lint's merge-base ratchet, ESLint's bulk
+  suppressions, and ruff on changed files. The plugin never writes them into a
+  repository. The gap linter's threshold line names the file and rule that would
+  hold a file-length limit; for Python, where ruff has no file-length rule, it says
+  that the gap linter holds it.
+
 - **A gap linter for the design triggers no linter holds.** `scripts/ldd-lint.sh`
   measures lines per source file (`file-length`) and source files per directory
   (`package-size`). Where the repository's linter config names a file-length rule,
@@ -27,6 +36,10 @@ Format based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/); versio
 
 ### Fixed
 
+- **The gap linter runs under bash 3.2.** macOS's `/bin/bash` stopped
+  `ldd-lint.sh` with a syntax error: bash 3.2 misreads a `case` pattern inside a
+  process substitution. The script now runs under bash 3.2 and bash 5.
+
 - **A value-taking option given last no longer hangs the review scripts.** When
   `ldd-detect.sh` or `ldd-scope.sh` got an option such as `--root` or `--base` as
   its last argument, the script looped forever. It now stops with "<option> needs
diff --git a/ts-react-linter-driven-development/README.md b/ts-react-linter-driven-development/README.md
index a0498f2..26f9bba 100644
--- a/ts-react-linter-driven-development/README.md
+++ b/ts-react-linter-driven-development/README.md
@@ -142,6 +142,11 @@ adds a checker the repository does not use.
   `@ts-expect-error`, `@ts-ignore`, `@ts-nocheck` and `// prettier-ignore`. The
   lint-fixer never adds one and never edits `eslint.config.*`, `tsconfig*.json` or
   `.prettierrc*`; a new one in a diff is itself a review finding.
+- **The recommended setup makes the design triggers fire.** `setup/eslint.config.ldd.mjs`
+  in the plugin directory is a flat-config fragment with every rule the routing
+  table routes to a design rule, at the limits the rules name. The plugin never
+  writes it into your repository: copy it beside `eslint.config.js` and spread it
+  into the exported array. Limits your configuration already sets stay yours.
 - **What it does not review.** Accessibility beyond what `jsx-a11y` flags —
   contrast, heading order, focus management, live regions — is the repository's
   axe run, which this plugin does not replace. Error-boundary placement and
diff --git a/ts-react-linter-driven-development/scripts/ldd-detect_test.sh b/ts-react-linter-driven-development/scripts/ldd-detect_test.sh
index a4aa109..d3feca1 100644
--- a/ts-react-linter-driven-development/scripts/ldd-detect_test.sh
+++ b/ts-react-linter-driven-development/scripts/ldd-detect_test.sh
@@ -141,6 +141,9 @@ questions_in_rules() {
 #   FX_BLOCK_OPEN      the line that opens a block comment, "" when the
 #   FX_BLOCK_CLOSE     language has none, and the line that closes it
 #   FX_SKIP_FILES      source file names a directory count leaves out
+#   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
+#                      the file-length limit, and FX_LENGTH_RULE its rule; both
+#                      "" when the language's linter has no file-length rule
 #   fx_test_file <dir> <n>             a test file's path in <dir>
 #   FX_LINTER_CONFIG   the path, under the repository root, of the file that
 #                      fx_write_linter_config writes, and FX_LINTER_COMMENT the
@@ -159,6 +162,8 @@ FX_NATIVE="typescript"
 # Every file the row writes is a `.ts` file, so both globs select the same set.
 use_row() {
   FX_LINTER_CONFIG='eslint.config.mjs'
+  FX_SETUP_FILE='eslint.config.ldd.mjs'
+  FX_LENGTH_RULE='sonarjs/max-lines'
   FX_LINTER_COMMENT='//'
   FX_EXT='.ts'
   FX_LINE_COMMENT='// note'
diff --git a/ts-react-linter-driven-development/scripts/ldd-lint.sh b/ts-react-linter-driven-development/scripts/ldd-lint.sh
index 9d83359..ee0318b 100755
--- a/ts-react-linter-driven-development/scripts/ldd-lint.sh
+++ b/ts-react-linter-driven-development/scripts/ldd-lint.sh
@@ -235,9 +235,15 @@ lang_is_test() {
 #                                   nothing. A named rule belongs to the linter:
 #                                   its limit, its counting and whether it is on
 #                                   are the repository's decision.
-#   lint_file_length_snippet <id> <max>  the linter setting that would hold the
-#                                   limit, or the .ldd-lint.yaml entry when no
-#                                   linter rule is known: text to propose
+#   lint_setup_files                one line per recommended config under the
+#                                   plugin's setup/: file TAB the tool that checks it
+#   lint_setup_check <file> <setup dir> <work dir>  run that tool's own check of
+#                                   the file; exit 0 when the tool accepts it
+#   lint_file_length_proposal <id>  what would hold the limit in the
+#                                   repository's linter: the rule, named after
+#                                   the plugin's recommended config under setup/
+#                                   that sets it, or the .ldd-lint.yaml entry when
+#                                   the language's linter has no such rule
 
 lint_comment_style() {
   case "$1" in
@@ -340,12 +346,27 @@ lint_file_length_rule() {
   return 0
 }
 
-lint_file_length_snippet() {
+lint_setup_files() {
+  printf 'golangci.yaml\tgolangci-lint\n'
+  printf 'ruff.toml\truff\n'
+  printf 'eslint.config.ldd.mjs\tnode\n'
+}
+
+lint_setup_check() { # <file> <setup dir> <work dir>
+  case "$1" in
+    golangci.yaml)         golangci-lint config verify -c "$2/$1" ;;
+    ruff.toml)             printf 'x = 1\n' > "$3/ldd_setup_check.py" && (cd "$3" && ruff check --no-cache --config "$2/$1" ldd_setup_check.py) ;;
+    eslint.config.ldd.mjs) node --check "$2/$1" ;;
+    *)                     return 2 ;;
+  esac
+}
+
+lint_file_length_proposal() {
   case "$1" in
-    go)                    printf "revive in .golangci.yaml: - name: file-length-limit, arguments: [{max: %s, skip-comments: true, skip-blank-lines: true}]" "$2" ;;
-    typescript|javascript) printf "the eslint config: 'sonarjs/max-lines': ['error', { maximum: %s }]" "$2" ;;
-    python)                printf "pyproject.toml: [tool.pylint.format] max-module-lines = %s (pylint counts every line, comments and blank lines too)" "$2" ;;
-    *)                     printf "no linter rule is known for %s; a .ldd-lint.yaml entry file_max_lines: %s would state this limit" "$1" "$2" ;;
+    go)                    printf "a setting to propose, never to add on your own: revive file-length-limit, as the plugin's setup/golangci.yaml sets it" ;;
+    typescript|javascript) printf "a setting to propose, never to add on your own: sonarjs/max-lines, as the plugin's setup/eslint.config.ldd.mjs sets it" ;;
+    python)                printf "ruff has no file-length rule, so this script holds the limit; a .ldd-lint.yaml entry file_max_lines: <n> states another" ;;
+    *)                     printf "no linter rule is known for %s; a .ldd-lint.yaml entry file_max_lines: <n> states another limit" "$1" ;;
   esac
 }
 # ================== end linter table ==================
@@ -417,6 +438,16 @@ trap 'rm -f "$SCOPE" "$INVENTORY"' EXIT
 list_candidates | by_language > "$SCOPE"
 if [[ -n "$FILES_LIST" ]]; then list_repo | by_language > "$INVENTORY"; else cp "$SCOPE" "$INVENTORY"; fi
 
+# dir_of <path> — the directory part of a relative path, "." for a file at
+# the root. A function, because bash 3.2 misreads a case pattern's ")" inside
+# a process substitution.
+dir_of() {
+  case "$1" in
+    */*) printf '%s\n' "${1%/*}" ;;
+    *)   printf '.\n' ;;
+  esac
+}
+
 # measured <path> — exit 0 when the file counts for this language: not under
 # an excluded directory, not a test, not generated. Every path the script
 # hands to find, head or awk starts with "./", and a directory is cut from a
@@ -448,7 +479,7 @@ run_file_length() { # <id> — every measured file of that language
     say "threshold: $id file length — set by $OVERRIDE_FILE ($max code lines)"
   else
     max="$DEFAULT_FILE_MAX_LINES"; src="profile default"
-    say "threshold: $id file length — profile default ($max code lines); the repository's linter does not hold it; a setting to propose, never to add on your own: $(lint_file_length_snippet "$id" "$max")"
+    say "threshold: $id file length — profile default ($max code lines); the repository's linter does not hold it; $(lint_file_length_proposal "$id")"
   fi
   while IFS=$'\t' read -r _ f; do
     measured "$f" || continue
@@ -472,7 +503,7 @@ run_package_size() { # <id> — every directory that holds a measured file of th
   awk -F'\t' -v id="$id" '$1 == id { print $2 }' "$INVENTORY" | while IFS= read -r f; do
     [[ -n "$skip" ]] && printf '%s\n' "$f" | grep -qE -- "$skip" && continue
     measured "$f" || continue
-    case "$f" in */*) printf '%s\n' "${f%/*}" ;; *) printf '.\n' ;; esac
+    dir_of "$f"
   done | LC_ALL=C sort | uniq -c | awk '{ n = $1; sub(/^[ \t]*[0-9]+[ \t]/, ""); print $0 "\t" n }' > "$counts"
   while IFS= read -r d; do
     n=$(awk -F'\t' -v d="$d" '$1 == d { print $2; exit }' "$counts")
@@ -483,8 +514,7 @@ run_package_size() { # <id> — every directory that holds a measured file of th
       finding "$d" "$n source files (warning at $warn, $src)"
     fi
   done < <(awk -F'\t' -v id="$id" '$1 == id { print $2 }' "$SCOPE" | while IFS= read -r f; do
-             measured "$f" || continue
-             case "$f" in */*) printf '%s\n' "${f%/*}" ;; *) printf '.\n' ;; esac
+             measured "$f" && dir_of "$f"
            done | LC_ALL=C sort -u)
   rm -f "$counts"
 }
diff --git a/ts-react-linter-driven-development/scripts/ldd-lint_test.sh b/ts-react-linter-driven-development/scripts/ldd-lint_test.sh
index 4a85f8c..287993c 100644
--- a/ts-react-linter-driven-development/scripts/ldd-lint_test.sh
+++ b/ts-react-linter-driven-development/scripts/ldd-lint_test.sh
@@ -105,6 +105,9 @@ fill_dir() {
 #   FX_BLOCK_OPEN      the line that opens a block comment, "" when the
 #   FX_BLOCK_CLOSE     language has none, and the line that closes it
 #   FX_SKIP_FILES      source file names a directory count leaves out
+#   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
+#                      the file-length limit, and FX_LENGTH_RULE its rule; both
+#                      "" when the language's linter has no file-length rule
 #   fx_test_file <dir> <n>             a test file's path in <dir>
 #   FX_LINTER_CONFIG   the path, under the repository root, of the file that
 #                      fx_write_linter_config writes, and FX_LINTER_COMMENT the
@@ -123,6 +126,8 @@ FX_NATIVE="typescript"
 # Every file the row writes is a `.ts` file, so both globs select the same set.
 use_row() {
   FX_LINTER_CONFIG='eslint.config.mjs'
+  FX_SETUP_FILE='eslint.config.ldd.mjs'
+  FX_LENGTH_RULE='sonarjs/max-lines'
   FX_LINTER_COMMENT='//'
   FX_EXT='.ts'
   FX_LINE_COMMENT='// note'
@@ -178,6 +183,165 @@ fx_write_linter_config_other() {
   printf "export default [{\n  rules: {\n    'max-lines-per-function': ['error', 50],\n    'sonarjs/max-lines-per-function': ['error', { maximum: 50 }],\n  },\n}]\n" > "$REPO/eslint.config.mjs"
 }
 
+# ==================== linter table ====================
+# What the gap linter needs to know per language id: how a comment is written,
+# which source files a directory count leaves out, and whether the
+# repository's own linter holds the file-length limit. The same table is
+# rendered into every plugin, so two plugins measure one file the same way.
+# residue-exempt: the table names every language's linter and config file on
+# purpose, the same in every rendering.
+#
+#   lint_comment_style <id>         c (// and /* */), d (also /+ +/) or hash (#)
+#   lint_strip_comments <style> <file>  the file with every comment removed and
+#                                   string literals kept, one output line per
+#                                   input line: a comment-only line prints empty.
+#                                   Styles: c, d, hash (# and triple-quoted
+#                                   strings), ini (# and a leading ;)
+#   lint_package_skip_re <id>       ERE over a relative path: source files a
+#                                   directory count leaves out (an index module,
+#                                   a package marker, generated stubs); "" for none
+#   lint_file_length_rule <id>      "<rule> in <config file>" when a linter config
+#                                   at the repository root names a file-length
+#                                   rule outside a comment, else
+#                                   nothing. A named rule belongs to the linter:
+#                                   its limit, its counting and whether it is on
+#                                   are the repository's decision.
+#   lint_setup_files                one line per recommended config under the
+#                                   plugin's setup/: file TAB the tool that checks it
+#   lint_setup_check <file> <setup dir> <work dir>  run that tool's own check of
+#                                   the file; exit 0 when the tool accepts it
+#   lint_file_length_proposal <id>  what would hold the limit in the
+#                                   repository's linter: the rule, named after
+#                                   the plugin's recommended config under setup/
+#                                   that sets it, or the .ldd-lint.yaml entry when
+#                                   the language's linter has no such rule
+
+lint_comment_style() {
+  case "$1" in
+    python|ruby|shell) printf 'hash' ;;
+    d)                 printf 'd' ;;
+    *)                 printf 'c' ;;
+  esac
+}
+
+lint_package_skip_re() {
+  case "$1" in
+    go)                    printf '%s' '(_gen|\.pb)\.go$' ;;
+    python)                printf '%s' '(^|/)(__init__|conftest)\.py$|_pb2(_grpc)?\.py$' ;;
+    typescript|javascript) printf '%s' '(^|/)index\.[cm]?[jt]sx?$|\.stories\.[cm]?[jt]sx?$' ;;
+  esac
+  return 0
+}
+
+# LINT_STRIP_AWK walks each line one character at a time. A quote opens a
+# string that a comment marker cannot end; single and double quotes close at
+# the end of the line, a backtick string (c and d) and a triple-quoted string
+# (hash) run on. A block comment may open after code and run on. The awk uses
+# substr and string compares only, so mawk, gawk and BSD awk read it alike.
+LINT_STRIP_AWK='
+BEGIN { bq = sprintf("%c", 96); sq = sprintf("%c", 39); dq = "\"" }
+{
+  line = $0; out = ""; n = length(line); i = 1
+  if (q == dq || q == sq) q = ""
+  while (i <= n) {
+    if (inblock) {
+      if (substr(line, i, length(closer)) == closer) { inblock = 0; i += length(closer); out = out " "; continue }
+      i++; continue
+    }
+    ch = substr(line, i, 1)
+    if (q != "") {
+      if (ch == "\\" && (q == dq || q == sq)) { out = out substr(line, i, 2); i += 2; continue }
+      if (substr(line, i, length(q)) == q) { out = out q; i += length(q); q = ""; continue }
+      out = out ch; i++; continue
+    }
+    if (style == "hash" || style == "ini") {
+      if (ch == "#") break
+      if (style == "ini" && ch == ";" && out ~ /^[ \t]*$/) break
+      three = substr(line, i, 3)
+      if (style == "hash" && (three == dq dq dq || three == sq sq sq)) { q = three; out = out three; i += 3; continue }
+    } else {
+      two = substr(line, i, 2)
+      if (two == "//") break
+      if (two == "/*" || (style == "d" && two == "/+")) { inblock = 1; closer = (two == "/+") ? "+/" : "*/"; out = out " "; i += 2; continue }
+      if (ch == bq) { q = bq; out = out ch; i++; continue }
+    }
+    if (ch == dq || ch == sq) { q = ch; out = out ch; i++; continue }
+    out = out ch; i++
+  }
+  print out
+}
+'
+
+lint_strip_comments() { # <style> <file>
+  awk -v style="$1" "$LINT_STRIP_AWK" "$2"
+}
+
+# _lint_config_style <config file> — how that config format writes a comment
+_lint_config_style() {
+  case "$1" in
+    *.yaml|*.yml|*.toml) printf 'hash' ;;
+    *.cfg|*.ini|.pylintrc|pylintrc) printf 'ini' ;;
+    *) printf 'c' ;;
+  esac
+}
+
+# _lint_names <ERE> <file>... — print the first file whose text outside its
+# comments matches the pattern
+_lint_names() {
+  local re="$1" f; shift
+  for f in "$@"; do
+    [[ -f "$f" ]] || continue
+    lint_strip_comments "$(_lint_config_style "$f")" "./$f" 2>/dev/null | grep -qE -- "$re" && { printf '%s' "$f"; return 0; }
+  done
+  return 1
+}
+
+lint_file_length_rule() {
+  local f
+  case "$1" in
+    go)
+      f=$(_lint_names 'file-length-limit' .golangci.yaml .golangci.yml .golangci.toml .golangci.json) \
+        && printf 'revive file-length-limit in %s' "$f" ;;
+    typescript|javascript)
+      local configs=(eslint.config.js eslint.config.mjs eslint.config.cjs eslint.config.ts eslint.config.mts eslint.config.cts
+                     .eslintrc .eslintrc.js .eslintrc.cjs .eslintrc.json .eslintrc.yml .eslintrc.yaml)
+      if f=$(_lint_names 'sonarjs/max-lines([^-a-zA-Z]|$)' "${configs[@]}"); then
+        printf 'sonarjs/max-lines in %s' "$f"
+      elif f=$(_lint_names '(^|[^-/a-zA-Z])max-lines([^-a-zA-Z]|$)' "${configs[@]}"); then
+        printf 'max-lines in %s' "$f"
+      fi ;;
+    python)
+      f=$(_lint_names '^[[:space:]]*max-module-lines[[:space:]]*=' pyproject.toml .pylintrc pylintrc setup.cfg tox.ini) \
+        && printf 'pylint max-module-lines in %s' "$f" ;;
+  esac
+  return 0
+}
+
+lint_setup_files() {
+  printf 'golangci.yaml\tgolangci-lint\n'
+  printf 'ruff.toml\truff\n'
+  printf 'eslint.config.ldd.mjs\tnode\n'
+}
+
+lint_setup_check() { # <file> <setup dir> <work dir>
+  case "$1" in
+    golangci.yaml)         golangci-lint config verify -c "$2/$1" ;;
+    ruff.toml)             printf 'x = 1\n' > "$3/ldd_setup_check.py" && (cd "$3" && ruff check --no-cache --config "$2/$1" ldd_setup_check.py) ;;
+    eslint.config.ldd.mjs) node --check "$2/$1" ;;
+    *)                     return 2 ;;
+  esac
+}
+
+lint_file_length_proposal() {
+  case "$1" in
+    go)                    printf "a setting to propose, never to add on your own: revive file-length-limit, as the plugin's setup/golangci.yaml sets it" ;;
+    typescript|javascript) printf "a setting to propose, never to add on your own: sonarjs/max-lines, as the plugin's setup/eslint.config.ldd.mjs sets it" ;;
+    python)                printf "ruff has no file-length rule, so this script holds the limit; a .ldd-lint.yaml entry file_max_lines: <n> states another" ;;
+    *)                     printf "no linter rule is known for %s; a .ldd-lint.yaml entry file_max_lines: <n> states another limit" "$1" ;;
+  esac
+}
+# ================== end linter table ==================
+
 # ========================= cases =========================
 run_row_cases() { # runs every case against the current row
 
@@ -237,7 +401,16 @@ finish
 begin "the plugin's default names a linter setting to propose, never to add"
 write_src "src/a$FX_EXT" 1
 run_lint file-length
-expect_exit 0 && expect_has "profile default ($MAX_LINES code lines)" && expect_has "a setting to propose, never to add on your own: " && ok
+SETUP_DIR="$(dirname "$LINT")/../setup"
+if [[ -n "$FX_SETUP_FILE" ]]; then
+  expect_exit 0 && expect_has "profile default ($MAX_LINES code lines)" \
+    && expect_has "a setting to propose, never to add on your own: " \
+    && expect_has "$FX_LENGTH_RULE, as the plugin's setup/$FX_SETUP_FILE sets it" \
+    && { grep -q -- "$FX_LENGTH_RULE" "$SETUP_DIR/$FX_SETUP_FILE" && grep -q -- "$MAX_LINES" "$SETUP_DIR/$FX_SETUP_FILE" || bad "setup/$FX_SETUP_FILE does not set $FX_LENGTH_RULE at $MAX_LINES"; } \
+    && grep -q -- "$FX_LENGTH_RULE" "$SETUP_DIR/$FX_SETUP_FILE" && ok
+else
+  expect_exit 0 && expect_has "profile default ($MAX_LINES code lines)" && expect_has "a .ldd-lint.yaml entry file_max_lines" && ok
+fi
 finish
 
 begin "a file-length rule in the linter config hands file length to the linter"
@@ -407,6 +580,18 @@ for opt in --root --files --glob --test-re; do
   finish
 done
 
+# --- the recommended configs under setup/, checked by their own linters when
+# the machine has them ---
+SETUP_DIR="$(dirname "$LINT")/../setup"
+
+while IFS=$'\t' read -r setup_file setup_tool; do
+  begin "setup/$setup_file passes its own linter's check"
+  if ! command -v "$setup_tool" >/dev/null 2>&1; then skip "$setup_tool is not on PATH"; finish; continue; fi
+  OUT=$(lint_setup_check "$setup_file" "$SETUP_DIR" "$REPO" 2>&1); CODE=$?; ERR=""
+  expect_exit 0 && ok
+  finish
+done < <(lint_setup_files)
+
 # ========================= summary =========================
 echo
 echo "ldd-lint_test: $pass passed, $failed failed, $skipped skipped"
diff --git a/ts-react-linter-driven-development/scripts/ldd-scope_test.sh b/ts-react-linter-driven-development/scripts/ldd-scope_test.sh
index 560308a..cac2339 100755
--- a/ts-react-linter-driven-development/scripts/ldd-scope_test.sh
+++ b/ts-react-linter-driven-development/scripts/ldd-scope_test.sh
@@ -117,6 +117,9 @@ mk_repo() { fx_write_marker "$REPO" fixture; fx_write_code; mk_docs; }
 #   FX_BLOCK_OPEN      the line that opens a block comment, "" when the
 #   FX_BLOCK_CLOSE     language has none, and the line that closes it
 #   FX_SKIP_FILES      source file names a directory count leaves out
+#   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
+#                      the file-length limit, and FX_LENGTH_RULE its rule; both
+#                      "" when the language's linter has no file-length rule
 #   fx_test_file <dir> <n>             a test file's path in <dir>
 #   FX_LINTER_CONFIG   the path, under the repository root, of the file that
 #                      fx_write_linter_config writes, and FX_LINTER_COMMENT the
@@ -135,6 +138,8 @@ FX_NATIVE="typescript"
 # Every file the row writes is a `.ts` file, so both globs select the same set.
 use_row() {
   FX_LINTER_CONFIG='eslint.config.mjs'
+  FX_SETUP_FILE='eslint.config.ldd.mjs'
+  FX_LENGTH_RULE='sonarjs/max-lines'
   FX_LINTER_COMMENT='//'
   FX_EXT='.ts'
   FX_LINE_COMMENT='// note'
diff --git a/ts-react-linter-driven-development/setup/eslint.config.ldd.mjs b/ts-react-linter-driven-development/setup/eslint.config.ldd.mjs
new file mode 100644
index 0000000..3e47c93
--- /dev/null
+++ b/ts-react-linter-driven-development/setup/eslint.config.ldd.mjs
@@ -0,0 +1,93 @@
+// Recommended ESLint flat-config fragment of the linter-driven-development
+// plugins: every rule the plugin's routing table routes to one of the twelve
+// design rules, at the limits the rules name. Each rule line says which rule its
+// failures feed. The plugin never writes this file into a repository: the
+// repository's owners copy it, or the parts they want, beside eslint.config.js
+// and spread it into the exported array:
+//
+//   import ldd from './eslint.config.ldd.mjs'
+//   export default [...yourConfig, ...ldd]
+//
+// residue-exempt: an ESLint configuration names its plugins and rules on purpose.
+// It needs eslint-plugin-sonarjs, eslint-plugin-react, eslint-plugin-react-hooks,
+// eslint-plugin-promise, eslint-plugin-import and typescript-eslint; a repository
+// that does not use one of them leaves its rules out. Limits a repository already
+// sets stay the repository's: the linter is the authority for every threshold it
+// holds. Rules this file leaves out (style, imports, formatting) are the
+// repository's own choice.
+//
+// Adopt it on an existing codebase with ESLint's bulk suppressions: run
+// `npx eslint --suppress-all` once to record today's violations, so only new ones
+// fail; `npx eslint --prune-suppressions` drops the entries that are fixed.
+
+import importPlugin from 'eslint-plugin-import'
+import promise from 'eslint-plugin-promise'
+import react from 'eslint-plugin-react'
+import reactHooks from 'eslint-plugin-react-hooks'
+import sonarjs from 'eslint-plugin-sonarjs'
+import tseslint from 'typescript-eslint'
+
+export default [
+  {
+    files: ['**/*.{ts,tsx}'],
+    plugins: {
+      '@typescript-eslint': tseslint.plugin,
+      import: importPlugin,
+      promise,
+      react,
+      'react-hooks': reactHooks,
+      sonarjs,
+    },
+    rules: {
+      // R3 storifying
+      'sonarjs/cognitive-complexity': ['error', 15],
+      'sonarjs/cyclomatic-complexity': ['error', { threshold: 10 }],
+      'sonarjs/expression-complexity': ['error', { max: 5 }],
+      'sonarjs/max-lines-per-function': ['error', { maximum: 200 }],
+      'sonarjs/nested-control-flow': ['error', { maximumNestingLevel: 4 }],
+      'sonarjs/no-nested-conditional': 'error',
+      'sonarjs/no-nested-functions': 'error',
+      'sonarjs/elseif-without-else': 'error',
+      'react/no-unstable-nested-components': 'error',
+      // R1 primitive obsession
+      'max-params': ['error', 4],
+      'sonarjs/no-duplicate-string': ['error', { threshold: 3 }],
+      'sonarjs/max-union-size': ['error', { threshold: 4 }],
+      'sonarjs/no-identical-functions': 'error',
+      // R2 self-validating types: parse at the boundary
+      '@typescript-eslint/no-explicit-any': 'error',
+      '@typescript-eslint/no-non-null-assertion': 'error',
+      // R5 vertical slice: one juicy module per file; counts code lines only
+      'sonarjs/max-lines': ['error', { maximum: 450 }],
+      'react/no-multi-comp': ['error', { ignoreStateless: false }],
+      // R8 no globals
+      'import/no-mutable-exports': 'error',
+      // R10 concurrency safety
+      'react-hooks/exhaustive-deps': 'error',
+      '@typescript-eslint/no-floating-promises': 'error',
+      '@typescript-eslint/no-misused-promises': 'error',
+      'promise/catch-or-return': 'error',
+      // R11 conditional dispatch
+      '@typescript-eslint/switch-exhaustiveness-check': 'error',
+      'sonarjs/no-nested-switch': 'error',
+      'sonarjs/max-switch-cases': 'error',
+      'sonarjs/no-small-switch': 'error',
+      // R12 mutation discipline
+      'no-param-reassign': ['error', { props: true }],
+      'sonarjs/prefer-read-only-props': 'error',
+      'react/no-direct-mutation-state': 'error',
+    },
+  },
+  {
+    // Tests are long and repeat literals by design.
+    files: ['**/*.test.{ts,tsx}', '**/*.spec.{ts,tsx}'],
+    rules: {
+      'sonarjs/max-lines-per-function': 'off',
+      'sonarjs/no-duplicate-string': 'off',
+      'sonarjs/no-nested-functions': 'off',
+      'max-params': 'off',
+      'react/no-multi-comp': 'off',
+      '@typescript-eslint/no-non-null-assertion': 'off',
+    },
+  },
+]
diff --git a/ts-react-linter-driven-development/setup/golangci.yaml b/ts-react-linter-driven-development/setup/golangci.yaml
new file mode 100644
index 0000000..da5ef91
--- /dev/null
+++ b/ts-react-linter-driven-development/setup/golangci.yaml
@@ -0,0 +1,82 @@
+# Recommended golangci-lint v2 configuration of the linter-driven-development
+# plugins: every linter rule the plugin's routing table routes to one of the
+# twelve design rules, at the limits the rules name. Each linter line says which
+# rule its failures feed. The plugin never writes this file into a repository:
+# the repository's owners copy it, or the parts they want, into .golangci.yaml.
+# residue-exempt: a golangci-lint configuration names its linters on purpose.
+#
+# Limits a repository already sets stay the repository's: the linter is the
+# authority for every threshold it holds. Rules this file leaves out (style,
+# naming, formatting) are the repository's own choice.
+#
+# Adopt it on an existing codebase with the ratchet below: only issues in code
+# changed since the merge base with main fail, so old code is not a wall of
+# findings on day one. Remove the ratchet once the old findings are gone.
+
+version: "2"
+
+issues:
+  new-from-merge-base: main
+
+linters:
+  default: none
+  enable:
+    - gocyclo           # R3 storifying: cyclomatic complexity
+    - gocognit          # R3 storifying: cognitive complexity
+    - funlen            # R3 storifying: function length
+    - nestif            # R3 storifying: nesting depth
+    - maintidx          # R3 storifying, R1 types: maintainability index
+    - dupl              # R1 types: duplicated logic; a duplicated switch is R11
+    - exhaustive        # R11 conditional dispatch: missing enum cases
+    - gochecknoglobals  # R8 no globals
+    - gochecknoinits    # R8 no globals
+    - ireturn           # R6 test-only interfaces: a constructor that returns an interface
+    - govet             # R10 concurrency: copylocks
+    - revive            # R1 types, R5 vertical slice: the rules below
+    - errcheck          # mechanical: an error that is not handled
+    - wrapcheck         # mechanical: an error without the context of its layer
+    - goconst           # mechanical; an enum-shaped string is R1's "Name enum strings"
+  settings:
+    gocyclo:
+      min-complexity: 10
+    gocognit:
+      min-complexity: 15
+    funlen:
+      lines: 50
+      statements: 40
+    nestif:
+      min-complexity: 2
+    maintidx:
+      under: 20
+    dupl:
+      threshold: 100
+    exhaustive:
+      # A default branch does not count as handling a case: every new case is
+      # handled where the switch is.
+      default-signifies-exhaustive: false
+    govet:
+      enable:
+        - copylocks
+    goconst:
+      min-len: 3
+      min-occurrences: 3
+    revive:
+      rules:
+        - name: argument-limit          # R1: more than 4 parameters wants a parameter object
+          arguments: [4]
+        - name: function-result-limit   # R1: more than 3 results wants a named result type
+          arguments: [3]
+        - name: file-length-limit       # R5: one juicy type per file; counts code lines only
+          arguments: [{max: 450, skip-comments: true, skip-blank-lines: true}]
+        - name: early-return            # mechanical: invert the condition and return early
+  exclusions:
+    rules:
+      # Tests are long and repeat literals by design.
+      - path: _test\.go
+        linters:
+          - funlen
+          - gocognit
+          - gocyclo
+          - maintidx
+          - dupl
+          - goconst
diff --git a/ts-react-linter-driven-development/setup/ruff.toml b/ts-react-linter-driven-development/setup/ruff.toml
new file mode 100644
index 0000000..36ce201
--- /dev/null
+++ b/ts-react-linter-driven-development/setup/ruff.toml
@@ -0,0 +1,53 @@
+# Recommended ruff configuration of the linter-driven-development plugins:
+# every rule the plugin's routing table routes to one of the twelve design
+# rules, at the limits the rules name. Each rule says which rule its failures
+# feed. The plugin never writes this file into a repository: the repository's
+# owners copy it, or the parts they want, into ruff.toml, or into
+# pyproject.toml with each table name prefixed by "tool.ruff." ([lint] becomes
+# [tool.ruff.lint]).
+# residue-exempt: a ruff configuration names its rule codes on purpose.
+#
+# Limits a repository already sets stay the repository's: the linter is the
+# authority for every threshold it holds. Rules this file leaves out (style,
+# docstrings, imports) are the repository's own choice. ruff has no file-length
+# rule: the plugin's gap linter, scripts/ldd-lint.sh file-length, holds that
+# limit at 450 code lines.
+#
+# Adopt it on an existing codebase one change at a time: run ruff on the files
+# changed since the merge base with main, so old code is not a wall of
+# findings on day one:
+#   git diff --name-only --diff-filter=d "$(git merge-base HEAD main)" -- '*.py' | xargs ruff check
+
+[lint]
+# PLR1702 (nested blocks) is a preview rule.
+preview = true
+explicit-preview-rules = true
+extend-select = [
+  "C901",     # R3 storifying: complexity
+  "PLR0911",  # R3 storifying: too many returns
+  "PLR0912",  # R3 storifying: too many branches
+  "PLR0915",  # R3 storifying: too many statements
+  "PLR1702",  # R3 storifying: nesting
+  "PLR0913",  # R1 types: too many arguments wants a parameter object
+  "PLR2004",  # R1 types: a magic value; an enum-shaped string is "Name enum strings"
+  "FBT001",   # R11 conditional dispatch: a boolean positional parameter
+  "FBT002",   # R11 conditional dispatch: a boolean default parameter
+  "PLW0603",  # R8 no globals: a global statement
+  "B006",     # R12 mutation discipline: a mutable default argument
+  "B008",     # R12 mutation discipline: a call in a default argument
+]
+
+[lint.mccabe]
+max-complexity = 8
+
+[lint.pylint]
+max-args = 4          # self and cls are not counted
+max-branches = 12
+max-returns = 6
+max-statements = 50
+max-nested-blocks = 5
+
+[lint.per-file-ignores]
+# Tests repeat literals and take many fixtures by design.
+"**/test_*.py" = ["PLR2004", "PLR0913", "FBT001", "FBT002"]
+"**/*_test.py" = ["PLR2004", "PLR0913", "FBT001", "FBT002"]

From 3b2553ee88d54658afae844b555a897805dfa010 Mon Sep 17 00:00:00 2001
From: Dan Mordechay <dan.mordechay@weka.io>
Date: Tue, 20 Oct 2026 14:48:47 +0300
Subject: [PATCH 2/3] setup: keep the repository's limits, cover every routed
 rule

- eslint.config.ldd.mjs: spread the fragment before the repository's own
  entries. Later entries win in flat config, so every limit the repository
  already sets stays the repository's. Before, the example put the fragment
  last, and it replaced those limits.
- eslint.config.ldd.mjs: add the routed rules it lacked: no-magic-numbers,
  react/no-array-index-key, @typescript-eslint/no-unsafe-*,
  @typescript-eslint/no-unnecessary-condition, react-hooks/set-state-in-effect.
  State the type-information requirement, and why no-restricted-syntax is
  left out.
- golangci.yaml: "default: standard" keeps golangci-lint's standard linters
  on; "none" turned off staticcheck, unused and ineffassign for anyone who
  copied the file. Note that the ratchet needs main in a CI clone.
- ruff.toml: say what preview mode also turns on.
- A matrix case reads each plugin's routing table and checks that the
  language's recommended config names every rule id routed to a design rule,
  except the ids the fixture row lists as left out on purpose.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 core/scripts/ldd-lint_test.sh                 | 23 ++++++++++++
 core/setup/eslint.config.ldd.mjs              | 33 +++++++++++++----
 core/setup/golangci.yaml                      |  8 +++--
 core/setup/ruff.toml                          |  4 ++-
 .../scripts/ldd-detect_test.sh                | 10 ++++++
 .../scripts/ldd-lint_test.sh                  | 33 +++++++++++++++++
 .../scripts/ldd-scope_test.sh                 | 10 ++++++
 .../setup/eslint.config.ldd.mjs               | 33 +++++++++++++----
 .../setup/golangci.yaml                       |  8 +++--
 go-linter-driven-development/setup/ruff.toml  |  4 ++-
 lang/generic/scripts/ldd-fixture.sh           | 12 +++++++
 lang/go/scripts/ldd-fixture.sh                | 10 ++++++
 lang/python/scripts/ldd-fixture.sh            |  9 +++++
 lang/ts-react/passthrough/README.md           |  3 +-
 lang/ts-react/scripts/ldd-fixture.sh          | 11 ++++++
 .../scripts/ldd-detect_test.sh                | 12 +++++++
 .../scripts/ldd-lint_test.sh                  | 35 +++++++++++++++++++
 .../scripts/ldd-scope_test.sh                 | 12 +++++++
 .../setup/eslint.config.ldd.mjs               | 33 +++++++++++++----
 linter-driven-development/setup/golangci.yaml |  8 +++--
 linter-driven-development/setup/ruff.toml     |  4 ++-
 .../scripts/ldd-detect_test.sh                |  9 +++++
 .../scripts/ldd-lint_test.sh                  | 32 +++++++++++++++++
 .../scripts/ldd-scope_test.sh                 |  9 +++++
 .../setup/eslint.config.ldd.mjs               | 33 +++++++++++++----
 .../setup/golangci.yaml                       |  8 +++--
 .../setup/ruff.toml                           |  4 ++-
 ts-react-linter-driven-development/README.md  |  3 +-
 .../scripts/ldd-detect_test.sh                | 11 ++++++
 .../scripts/ldd-lint_test.sh                  | 34 ++++++++++++++++++
 .../scripts/ldd-scope_test.sh                 | 11 ++++++
 .../setup/eslint.config.ldd.mjs               | 33 +++++++++++++----
 .../setup/golangci.yaml                       |  8 +++--
 .../setup/ruff.toml                           |  4 ++-
 34 files changed, 467 insertions(+), 47 deletions(-)

diff --git a/core/scripts/ldd-lint_test.sh b/core/scripts/ldd-lint_test.sh
index d0ee69b..d63f497 100644
--- a/core/scripts/ldd-lint_test.sh
+++ b/core/scripts/ldd-lint_test.sh
@@ -189,6 +189,29 @@ run_lint file-length
 expect_exit 0 && expect_not "held by " && expect_has "src/over$FX_EXT: $((MAX_LINES + 1)) code lines" && ok
 finish
 
+begin "the recommended config enables every rule the routing table routes to a design rule"
+if [[ -z "$FX_ROUTED_FILE" ]]; then skip "this plugin's routing table names no linter rule"; finish
+else
+  table=$(grep -l '^| Linter failure | Route |' "$(dirname "$LINT")"/../skills/refactoring/*.md | head -1)
+  missing=""; checked=0
+  while IFS= read -r id; do
+    case " $FX_ROUTED_SKIP " in *" $id "*) continue ;; esac
+    checked=$((checked + 1))
+    case "$id" in
+      *'*') re="(^|[^A-Za-z0-9/@-])${id%\*}" ;;
+      *)    re="(^|[^A-Za-z0-9/@-])${id}([^A-Za-z0-9/-]|\$)" ;;
+    esac
+    grep -qE -- "$re" "$(dirname "$LINT")/../setup/$FX_ROUTED_FILE" || missing="$missing $id"
+  done < <(awk -F'|' '
+      /^\| Linter failure \| Route \|/ { t = 1; next }
+      t && /^\|---/ { next }
+      t && /^\|/ { if ($3 ~ /rules\/R/) { c = $2; while (match(c, /`[^`]+`/)) { print substr(c, RSTART + 1, RLENGTH - 2); c = substr(c, RSTART + RLENGTH) } } next }
+      t { t = 0 }' "$table" | grep -E -- "$FX_RULE_ID_RE" | LC_ALL=C sort -u)
+  { [[ -n "$table" ]] && (( checked > 0 )) || bad "no routed rule id found in the routing table"; } \
+    && { [[ -z "$missing" ]] || bad "setup/$FX_ROUTED_FILE lacks:$missing"; } && [[ -z "$missing" ]] && ok
+  finish
+fi
+
 begin ".ldd-lint.yaml sets the limit when the linter holds none"
 printf 'file_max_lines: 100  # this repository\n' > "$REPO/.ldd-lint.yaml"
 write_src "src/a$FX_EXT" 101
diff --git a/core/setup/eslint.config.ldd.mjs b/core/setup/eslint.config.ldd.mjs
index f31218c..936e99a 100644
--- a/core/setup/eslint.config.ldd.mjs
+++ b/core/setup/eslint.config.ldd.mjs
@@ -3,18 +3,23 @@
 // design rules, at the limits the rules name. Each rule line says which rule its
 // failures feed. The plugin never writes this file into a repository: the
 // repository's owners copy it, or the parts they want, beside eslint.config.js
-// and spread it into the exported array:
+// and spread it before their own entries. Later entries win, so every limit the
+// repository's config already sets stays the repository's:
 //
 //   import ldd from './eslint.config.ldd.mjs'
-//   export default [...yourConfig, ...ldd]
+//   export default [...ldd, ...yourConfig]
 //
 // residue-exempt: an ESLint configuration names its plugins and rules on purpose.
 // It needs eslint-plugin-sonarjs, eslint-plugin-react, eslint-plugin-react-hooks,
 // eslint-plugin-promise, eslint-plugin-import and typescript-eslint; a repository
-// that does not use one of them leaves its rules out. Limits a repository already
-// sets stay the repository's: the linter is the authority for every threshold it
-// holds. Rules this file leaves out (style, imports, formatting) are the
-// repository's own choice.
+// that does not use one of them leaves its rules out. The @typescript-eslint rules
+// below need type information: the repository's config sets typescript-eslint's
+// parser with parserOptions.projectService for these files, or ESLint stops with
+// an error. Limits a repository already sets stay the repository's: the linter is
+// the authority for every threshold it holds. Rules this file leaves out (style,
+// imports, formatting) are the repository's own choice, and so is
+// no-restricted-syntax on import.meta.env outside the config module (R8): the
+// config module's path is the repository's.
 //
 // Adopt it on an existing codebase with ESLint's bulk suppressions: run
 // `npx eslint --suppress-all` once to record today's violations, so only new ones
@@ -54,9 +59,23 @@ export default [
       'sonarjs/no-duplicate-string': ['error', { threshold: 3 }],
       'sonarjs/max-union-size': ['error', { threshold: 4 }],
       'sonarjs/no-identical-functions': 'error',
+      'react/no-array-index-key': 'error',
+      'no-magic-numbers': ['error', {
+        ignore: [-1, 0, 1, 2],
+        ignoreArrayIndexes: true,
+        ignoreDefaultValues: true,
+        ignoreClassFieldInitialValues: true,
+        detectObjects: false,
+      }],
       // R2 self-validating types: parse at the boundary
       '@typescript-eslint/no-explicit-any': 'error',
       '@typescript-eslint/no-non-null-assertion': 'error',
+      '@typescript-eslint/no-unsafe-argument': 'error',
+      '@typescript-eslint/no-unsafe-assignment': 'error',
+      '@typescript-eslint/no-unsafe-call': 'error',
+      '@typescript-eslint/no-unsafe-member-access': 'error',
+      '@typescript-eslint/no-unsafe-return': 'error',
+      '@typescript-eslint/no-unnecessary-condition': 'error',
       // R5 vertical slice: one juicy module per file; counts code lines only
       'sonarjs/max-lines': ['error', { maximum: {{.FileMaxLines}} }],
       'react/no-multi-comp': ['error', { ignoreStateless: false }],
@@ -64,6 +83,7 @@ export default [
       'import/no-mutable-exports': 'error',
       // R10 concurrency safety
       'react-hooks/exhaustive-deps': 'error',
+      'react-hooks/set-state-in-effect': 'error',
       '@typescript-eslint/no-floating-promises': 'error',
       '@typescript-eslint/no-misused-promises': 'error',
       'promise/catch-or-return': 'error',
@@ -86,6 +106,7 @@ export default [
       'sonarjs/no-duplicate-string': 'off',
       'sonarjs/no-nested-functions': 'off',
       'max-params': 'off',
+      'no-magic-numbers': 'off',
       'react/no-multi-comp': 'off',
       '@typescript-eslint/no-non-null-assertion': 'off',
     },
diff --git a/core/setup/golangci.yaml b/core/setup/golangci.yaml
index 6e32efb..be5a0ac 100644
--- a/core/setup/golangci.yaml
+++ b/core/setup/golangci.yaml
@@ -11,7 +11,9 @@
 #
 # Adopt it on an existing codebase with the ratchet below: only issues in code
 # changed since the merge base with main fail, so old code is not a wall of
-# findings on day one. Remove the ratchet once the old findings are gone.
+# findings on day one. CI needs main in the clone for it (fetch-depth: 0 in
+# GitHub Actions). Remove the ratchet once the old findings are gone.
+# gocyclo stands for the routing table's "gocyclo / cyclop": enable one of the two.
 
 version: "2"
 
@@ -19,7 +21,9 @@ issues:
   new-from-merge-base: main
 
 linters:
-  default: none
+  # The standard set (errcheck, govet, ineffassign, staticcheck, unused) stays on;
+  # the linters below are added to it.
+  default: standard
   enable:
     - gocyclo           # R3 storifying: cyclomatic complexity
     - gocognit          # R3 storifying: cognitive complexity
diff --git a/core/setup/ruff.toml b/core/setup/ruff.toml
index 1ffb4c6..b4ee32e 100644
--- a/core/setup/ruff.toml
+++ b/core/setup/ruff.toml
@@ -19,7 +19,9 @@
 #   git diff --name-only --diff-filter=d "$(git merge-base HEAD main)" -- '*.py' | xargs ruff check
 
 [lint]
-# PLR1702 (nested blocks) is a preview rule.
+# PLR1702 (nested blocks) is a preview rule. Preview mode also turns on preview
+# behavior of the stable rules a repository already selects; a repository that
+# does not want that drops these two lines and PLR1702.
 preview = true
 explicit-preview-rules = true
 extend-select = [
diff --git a/go-linter-driven-development/scripts/ldd-detect_test.sh b/go-linter-driven-development/scripts/ldd-detect_test.sh
index 24b78bb..3068f63 100644
--- a/go-linter-driven-development/scripts/ldd-detect_test.sh
+++ b/go-linter-driven-development/scripts/ldd-detect_test.sh
@@ -141,6 +141,12 @@ questions_in_rules() {
 #   FX_BLOCK_OPEN      the line that opens a block comment, "" when the
 #   FX_BLOCK_CLOSE     language has none, and the line that closes it
 #   FX_SKIP_FILES      source file names a directory count leaves out
+#   FX_ROUTED_FILE     the plugin's recommended config under setup/ for the
+#                      language, which enables every rule id the refactoring
+#                      routing table routes to a design rule; FX_RULE_ID_RE the
+#                      shape of the language's rule ids in that table, and
+#                      FX_ROUTED_SKIP the ids the config leaves out on purpose;
+#                      all "" when the plugin's table names no linter rule
 #   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
 #                      the file-length limit, and FX_LENGTH_RULE its rule; both
 #                      "" when the language's linter has no file-length rule
@@ -160,6 +166,10 @@ FX_NATIVE="go"
 use_row() {
   FX_LINTER_CONFIG='.golangci.yaml'
   FX_SETUP_FILE='golangci.yaml'
+  FX_ROUTED_FILE='golangci.yaml'
+  FX_RULE_ID_RE='^[a-z][a-z0-9-]*$'
+  # cyclop is the alternative to gocyclo; package-size is the gap linter's
+  FX_ROUTED_SKIP='cyclop package-size'
   FX_LENGTH_RULE='file-length-limit'
   FX_LINTER_COMMENT='#'
   FX_EXT='.go'
diff --git a/go-linter-driven-development/scripts/ldd-lint_test.sh b/go-linter-driven-development/scripts/ldd-lint_test.sh
index 5192d27..b66dd24 100644
--- a/go-linter-driven-development/scripts/ldd-lint_test.sh
+++ b/go-linter-driven-development/scripts/ldd-lint_test.sh
@@ -105,6 +105,12 @@ fill_dir() {
 #   FX_BLOCK_OPEN      the line that opens a block comment, "" when the
 #   FX_BLOCK_CLOSE     language has none, and the line that closes it
 #   FX_SKIP_FILES      source file names a directory count leaves out
+#   FX_ROUTED_FILE     the plugin's recommended config under setup/ for the
+#                      language, which enables every rule id the refactoring
+#                      routing table routes to a design rule; FX_RULE_ID_RE the
+#                      shape of the language's rule ids in that table, and
+#                      FX_ROUTED_SKIP the ids the config leaves out on purpose;
+#                      all "" when the plugin's table names no linter rule
 #   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
 #                      the file-length limit, and FX_LENGTH_RULE its rule; both
 #                      "" when the language's linter has no file-length rule
@@ -124,6 +130,10 @@ FX_NATIVE="go"
 use_row() {
   FX_LINTER_CONFIG='.golangci.yaml'
   FX_SETUP_FILE='golangci.yaml'
+  FX_ROUTED_FILE='golangci.yaml'
+  FX_RULE_ID_RE='^[a-z][a-z0-9-]*$'
+  # cyclop is the alternative to gocyclo; package-size is the gap linter's
+  FX_ROUTED_SKIP='cyclop package-size'
   FX_LENGTH_RULE='file-length-limit'
   FX_LINTER_COMMENT='#'
   FX_EXT='.go'
@@ -444,6 +454,29 @@ run_lint file-length
 expect_exit 0 && expect_not "held by " && expect_has "src/over$FX_EXT: $((MAX_LINES + 1)) code lines" && ok
 finish
 
+begin "the recommended config enables every rule the routing table routes to a design rule"
+if [[ -z "$FX_ROUTED_FILE" ]]; then skip "this plugin's routing table names no linter rule"; finish
+else
+  table=$(grep -l '^| Linter failure | Route |' "$(dirname "$LINT")"/../skills/refactoring/*.md | head -1)
+  missing=""; checked=0
+  while IFS= read -r id; do
+    case " $FX_ROUTED_SKIP " in *" $id "*) continue ;; esac
+    checked=$((checked + 1))
+    case "$id" in
+      *'*') re="(^|[^A-Za-z0-9/@-])${id%\*}" ;;
+      *)    re="(^|[^A-Za-z0-9/@-])${id}([^A-Za-z0-9/-]|\$)" ;;
+    esac
+    grep -qE -- "$re" "$(dirname "$LINT")/../setup/$FX_ROUTED_FILE" || missing="$missing $id"
+  done < <(awk -F'|' '
+      /^\| Linter failure \| Route \|/ { t = 1; next }
+      t && /^\|---/ { next }
+      t && /^\|/ { if ($3 ~ /rules\/R/) { c = $2; while (match(c, /`[^`]+`/)) { print substr(c, RSTART + 1, RLENGTH - 2); c = substr(c, RSTART + RLENGTH) } } next }
+      t { t = 0 }' "$table" | grep -E -- "$FX_RULE_ID_RE" | LC_ALL=C sort -u)
+  { [[ -n "$table" ]] && (( checked > 0 )) || bad "no routed rule id found in the routing table"; } \
+    && { [[ -z "$missing" ]] || bad "setup/$FX_ROUTED_FILE lacks:$missing"; } && [[ -z "$missing" ]] && ok
+  finish
+fi
+
 begin ".ldd-lint.yaml sets the limit when the linter holds none"
 printf 'file_max_lines: 100  # this repository\n' > "$REPO/.ldd-lint.yaml"
 write_src "src/a$FX_EXT" 101
diff --git a/go-linter-driven-development/scripts/ldd-scope_test.sh b/go-linter-driven-development/scripts/ldd-scope_test.sh
index 954433b..eaebc6e 100755
--- a/go-linter-driven-development/scripts/ldd-scope_test.sh
+++ b/go-linter-driven-development/scripts/ldd-scope_test.sh
@@ -117,6 +117,12 @@ mk_repo() { fx_write_marker "$REPO" fixture; fx_write_code; mk_docs; }
 #   FX_BLOCK_OPEN      the line that opens a block comment, "" when the
 #   FX_BLOCK_CLOSE     language has none, and the line that closes it
 #   FX_SKIP_FILES      source file names a directory count leaves out
+#   FX_ROUTED_FILE     the plugin's recommended config under setup/ for the
+#                      language, which enables every rule id the refactoring
+#                      routing table routes to a design rule; FX_RULE_ID_RE the
+#                      shape of the language's rule ids in that table, and
+#                      FX_ROUTED_SKIP the ids the config leaves out on purpose;
+#                      all "" when the plugin's table names no linter rule
 #   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
 #                      the file-length limit, and FX_LENGTH_RULE its rule; both
 #                      "" when the language's linter has no file-length rule
@@ -136,6 +142,10 @@ FX_NATIVE="go"
 use_row() {
   FX_LINTER_CONFIG='.golangci.yaml'
   FX_SETUP_FILE='golangci.yaml'
+  FX_ROUTED_FILE='golangci.yaml'
+  FX_RULE_ID_RE='^[a-z][a-z0-9-]*$'
+  # cyclop is the alternative to gocyclo; package-size is the gap linter's
+  FX_ROUTED_SKIP='cyclop package-size'
   FX_LENGTH_RULE='file-length-limit'
   FX_LINTER_COMMENT='#'
   FX_EXT='.go'
diff --git a/go-linter-driven-development/setup/eslint.config.ldd.mjs b/go-linter-driven-development/setup/eslint.config.ldd.mjs
index 3e47c93..4ccd360 100644
--- a/go-linter-driven-development/setup/eslint.config.ldd.mjs
+++ b/go-linter-driven-development/setup/eslint.config.ldd.mjs
@@ -3,18 +3,23 @@
 // design rules, at the limits the rules name. Each rule line says which rule its
 // failures feed. The plugin never writes this file into a repository: the
 // repository's owners copy it, or the parts they want, beside eslint.config.js
-// and spread it into the exported array:
+// and spread it before their own entries. Later entries win, so every limit the
+// repository's config already sets stays the repository's:
 //
 //   import ldd from './eslint.config.ldd.mjs'
-//   export default [...yourConfig, ...ldd]
+//   export default [...ldd, ...yourConfig]
 //
 // residue-exempt: an ESLint configuration names its plugins and rules on purpose.
 // It needs eslint-plugin-sonarjs, eslint-plugin-react, eslint-plugin-react-hooks,
 // eslint-plugin-promise, eslint-plugin-import and typescript-eslint; a repository
-// that does not use one of them leaves its rules out. Limits a repository already
-// sets stay the repository's: the linter is the authority for every threshold it
-// holds. Rules this file leaves out (style, imports, formatting) are the
-// repository's own choice.
+// that does not use one of them leaves its rules out. The @typescript-eslint rules
+// below need type information: the repository's config sets typescript-eslint's
+// parser with parserOptions.projectService for these files, or ESLint stops with
+// an error. Limits a repository already sets stay the repository's: the linter is
+// the authority for every threshold it holds. Rules this file leaves out (style,
+// imports, formatting) are the repository's own choice, and so is
+// no-restricted-syntax on import.meta.env outside the config module (R8): the
+// config module's path is the repository's.
 //
 // Adopt it on an existing codebase with ESLint's bulk suppressions: run
 // `npx eslint --suppress-all` once to record today's violations, so only new ones
@@ -54,9 +59,23 @@ export default [
       'sonarjs/no-duplicate-string': ['error', { threshold: 3 }],
       'sonarjs/max-union-size': ['error', { threshold: 4 }],
       'sonarjs/no-identical-functions': 'error',
+      'react/no-array-index-key': 'error',
+      'no-magic-numbers': ['error', {
+        ignore: [-1, 0, 1, 2],
+        ignoreArrayIndexes: true,
+        ignoreDefaultValues: true,
+        ignoreClassFieldInitialValues: true,
+        detectObjects: false,
+      }],
       // R2 self-validating types: parse at the boundary
       '@typescript-eslint/no-explicit-any': 'error',
       '@typescript-eslint/no-non-null-assertion': 'error',
+      '@typescript-eslint/no-unsafe-argument': 'error',
+      '@typescript-eslint/no-unsafe-assignment': 'error',
+      '@typescript-eslint/no-unsafe-call': 'error',
+      '@typescript-eslint/no-unsafe-member-access': 'error',
+      '@typescript-eslint/no-unsafe-return': 'error',
+      '@typescript-eslint/no-unnecessary-condition': 'error',
       // R5 vertical slice: one juicy module per file; counts code lines only
       'sonarjs/max-lines': ['error', { maximum: 450 }],
       'react/no-multi-comp': ['error', { ignoreStateless: false }],
@@ -64,6 +83,7 @@ export default [
       'import/no-mutable-exports': 'error',
       // R10 concurrency safety
       'react-hooks/exhaustive-deps': 'error',
+      'react-hooks/set-state-in-effect': 'error',
       '@typescript-eslint/no-floating-promises': 'error',
       '@typescript-eslint/no-misused-promises': 'error',
       'promise/catch-or-return': 'error',
@@ -86,6 +106,7 @@ export default [
       'sonarjs/no-duplicate-string': 'off',
       'sonarjs/no-nested-functions': 'off',
       'max-params': 'off',
+      'no-magic-numbers': 'off',
       'react/no-multi-comp': 'off',
       '@typescript-eslint/no-non-null-assertion': 'off',
     },
diff --git a/go-linter-driven-development/setup/golangci.yaml b/go-linter-driven-development/setup/golangci.yaml
index da5ef91..fd73147 100644
--- a/go-linter-driven-development/setup/golangci.yaml
+++ b/go-linter-driven-development/setup/golangci.yaml
@@ -11,7 +11,9 @@
 #
 # Adopt it on an existing codebase with the ratchet below: only issues in code
 # changed since the merge base with main fail, so old code is not a wall of
-# findings on day one. Remove the ratchet once the old findings are gone.
+# findings on day one. CI needs main in the clone for it (fetch-depth: 0 in
+# GitHub Actions). Remove the ratchet once the old findings are gone.
+# gocyclo stands for the routing table's "gocyclo / cyclop": enable one of the two.
 
 version: "2"
 
@@ -19,7 +21,9 @@ issues:
   new-from-merge-base: main
 
 linters:
-  default: none
+  # The standard set (errcheck, govet, ineffassign, staticcheck, unused) stays on;
+  # the linters below are added to it.
+  default: standard
   enable:
     - gocyclo           # R3 storifying: cyclomatic complexity
     - gocognit          # R3 storifying: cognitive complexity
diff --git a/go-linter-driven-development/setup/ruff.toml b/go-linter-driven-development/setup/ruff.toml
index 36ce201..1f91e7f 100644
--- a/go-linter-driven-development/setup/ruff.toml
+++ b/go-linter-driven-development/setup/ruff.toml
@@ -19,7 +19,9 @@
 #   git diff --name-only --diff-filter=d "$(git merge-base HEAD main)" -- '*.py' | xargs ruff check
 
 [lint]
-# PLR1702 (nested blocks) is a preview rule.
+# PLR1702 (nested blocks) is a preview rule. Preview mode also turns on preview
+# behavior of the stable rules a repository already selects; a repository that
+# does not want that drops these two lines and PLR1702.
 preview = true
 explicit-preview-rules = true
 extend-select = [
diff --git a/lang/generic/scripts/ldd-fixture.sh b/lang/generic/scripts/ldd-fixture.sh
index d315b53..1dab74d 100644
--- a/lang/generic/scripts/ldd-fixture.sh
+++ b/lang/generic/scripts/ldd-fixture.sh
@@ -18,6 +18,12 @@
 #   FX_BLOCK_OPEN      the line that opens a block comment, "" when the
 #   FX_BLOCK_CLOSE     language has none, and the line that closes it
 #   FX_SKIP_FILES      source file names a directory count leaves out
+#   FX_ROUTED_FILE     the plugin's recommended config under setup/ for the
+#                      language, which enables every rule id the refactoring
+#                      routing table routes to a design rule; FX_RULE_ID_RE the
+#                      shape of the language's rule ids in that table, and
+#                      FX_ROUTED_SKIP the ids the config leaves out on purpose;
+#                      all "" when the plugin's table names no linter rule
 #   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
 #                      the file-length limit, and FX_LENGTH_RULE its rule; both
 #                      "" when the language's linter has no file-length rule
@@ -39,6 +45,9 @@ use_row() {
     go)
       FX_LINTER_CONFIG='.golangci.yml'
       FX_SETUP_FILE='golangci.yaml'
+      FX_ROUTED_FILE=''
+      FX_RULE_ID_RE=''
+      FX_ROUTED_SKIP=''
       FX_LENGTH_RULE='file-length-limit'
       FX_LINTER_COMMENT='#'
       FX_EXT='.go'
@@ -53,6 +62,9 @@ use_row() {
     python)
       FX_LINTER_CONFIG='.pylintrc'
       FX_SETUP_FILE=''
+      FX_ROUTED_FILE=''
+      FX_RULE_ID_RE=''
+      FX_ROUTED_SKIP=''
       FX_LENGTH_RULE=''
       FX_LINTER_COMMENT=';'
       FX_EXT='.py'
diff --git a/lang/go/scripts/ldd-fixture.sh b/lang/go/scripts/ldd-fixture.sh
index 2ddfac6..472d464 100644
--- a/lang/go/scripts/ldd-fixture.sh
+++ b/lang/go/scripts/ldd-fixture.sh
@@ -18,6 +18,12 @@
 #   FX_BLOCK_OPEN      the line that opens a block comment, "" when the
 #   FX_BLOCK_CLOSE     language has none, and the line that closes it
 #   FX_SKIP_FILES      source file names a directory count leaves out
+#   FX_ROUTED_FILE     the plugin's recommended config under setup/ for the
+#                      language, which enables every rule id the refactoring
+#                      routing table routes to a design rule; FX_RULE_ID_RE the
+#                      shape of the language's rule ids in that table, and
+#                      FX_ROUTED_SKIP the ids the config leaves out on purpose;
+#                      all "" when the plugin's table names no linter rule
 #   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
 #                      the file-length limit, and FX_LENGTH_RULE its rule; both
 #                      "" when the language's linter has no file-length rule
@@ -37,6 +43,10 @@ FX_NATIVE="go"
 use_row() {
   FX_LINTER_CONFIG='.golangci.yaml'
   FX_SETUP_FILE='golangci.yaml'
+  FX_ROUTED_FILE='golangci.yaml'
+  FX_RULE_ID_RE='^[a-z][a-z0-9-]*$'
+  # cyclop is the alternative to gocyclo; package-size is the gap linter's
+  FX_ROUTED_SKIP='cyclop package-size'
   FX_LENGTH_RULE='file-length-limit'
   FX_LINTER_COMMENT='#'
   FX_EXT='.go'
diff --git a/lang/python/scripts/ldd-fixture.sh b/lang/python/scripts/ldd-fixture.sh
index 9d6eabf..cdcde9b 100644
--- a/lang/python/scripts/ldd-fixture.sh
+++ b/lang/python/scripts/ldd-fixture.sh
@@ -18,6 +18,12 @@
 #   FX_BLOCK_OPEN      the line that opens a block comment, "" when the
 #   FX_BLOCK_CLOSE     language has none, and the line that closes it
 #   FX_SKIP_FILES      source file names a directory count leaves out
+#   FX_ROUTED_FILE     the plugin's recommended config under setup/ for the
+#                      language, which enables every rule id the refactoring
+#                      routing table routes to a design rule; FX_RULE_ID_RE the
+#                      shape of the language's rule ids in that table, and
+#                      FX_ROUTED_SKIP the ids the config leaves out on purpose;
+#                      all "" when the plugin's table names no linter rule
 #   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
 #                      the file-length limit, and FX_LENGTH_RULE its rule; both
 #                      "" when the language's linter has no file-length rule
@@ -37,6 +43,9 @@ FX_NATIVE="python"
 use_row() {
   FX_LINTER_CONFIG='pyproject.toml'
   FX_SETUP_FILE=''
+  FX_ROUTED_FILE='ruff.toml'
+  FX_RULE_ID_RE='^[A-Z]+[0-9]+$'
+  FX_ROUTED_SKIP=''
   FX_LENGTH_RULE=''
   FX_LINTER_COMMENT='#'
   FX_EXT='.py'
diff --git a/lang/ts-react/passthrough/README.md b/lang/ts-react/passthrough/README.md
index 26f9bba..3117d92 100644
--- a/lang/ts-react/passthrough/README.md
+++ b/lang/ts-react/passthrough/README.md
@@ -146,7 +146,8 @@ adds a checker the repository does not use.
   in the plugin directory is a flat-config fragment with every rule the routing
   table routes to a design rule, at the limits the rules name. The plugin never
   writes it into your repository: copy it beside `eslint.config.js` and spread it
-  into the exported array. Limits your configuration already sets stay yours.
+  before your own entries, so every limit your configuration already sets stays
+  yours.
 - **What it does not review.** Accessibility beyond what `jsx-a11y` flags —
   contrast, heading order, focus management, live regions — is the repository's
   axe run, which this plugin does not replace. Error-boundary placement and
diff --git a/lang/ts-react/scripts/ldd-fixture.sh b/lang/ts-react/scripts/ldd-fixture.sh
index 6f70b96..334600e 100644
--- a/lang/ts-react/scripts/ldd-fixture.sh
+++ b/lang/ts-react/scripts/ldd-fixture.sh
@@ -18,6 +18,12 @@
 #   FX_BLOCK_OPEN      the line that opens a block comment, "" when the
 #   FX_BLOCK_CLOSE     language has none, and the line that closes it
 #   FX_SKIP_FILES      source file names a directory count leaves out
+#   FX_ROUTED_FILE     the plugin's recommended config under setup/ for the
+#                      language, which enables every rule id the refactoring
+#                      routing table routes to a design rule; FX_RULE_ID_RE the
+#                      shape of the language's rule ids in that table, and
+#                      FX_ROUTED_SKIP the ids the config leaves out on purpose;
+#                      all "" when the plugin's table names no linter rule
 #   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
 #                      the file-length limit, and FX_LENGTH_RULE its rule; both
 #                      "" when the language's linter has no file-length rule
@@ -40,6 +46,11 @@ FX_NATIVE="typescript"
 use_row() {
   FX_LINTER_CONFIG='eslint.config.mjs'
   FX_SETUP_FILE='eslint.config.ldd.mjs'
+  FX_ROUTED_FILE='eslint.config.ldd.mjs'
+  FX_RULE_ID_RE='^(@[a-z-]+/)?[a-z-]+(/[a-z*-]+)?$'
+  # no-restricted-syntax needs the repository's config module path;
+  # package-size is the gap linter's
+  FX_ROUTED_SKIP='no-restricted-syntax package-size'
   FX_LENGTH_RULE='sonarjs/max-lines'
   FX_LINTER_COMMENT='//'
   FX_EXT='.ts'
diff --git a/linter-driven-development/scripts/ldd-detect_test.sh b/linter-driven-development/scripts/ldd-detect_test.sh
index 7b23daf..9a709b5 100644
--- a/linter-driven-development/scripts/ldd-detect_test.sh
+++ b/linter-driven-development/scripts/ldd-detect_test.sh
@@ -141,6 +141,12 @@ questions_in_rules() {
 #   FX_BLOCK_OPEN      the line that opens a block comment, "" when the
 #   FX_BLOCK_CLOSE     language has none, and the line that closes it
 #   FX_SKIP_FILES      source file names a directory count leaves out
+#   FX_ROUTED_FILE     the plugin's recommended config under setup/ for the
+#                      language, which enables every rule id the refactoring
+#                      routing table routes to a design rule; FX_RULE_ID_RE the
+#                      shape of the language's rule ids in that table, and
+#                      FX_ROUTED_SKIP the ids the config leaves out on purpose;
+#                      all "" when the plugin's table names no linter rule
 #   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
 #                      the file-length limit, and FX_LENGTH_RULE its rule; both
 #                      "" when the language's linter has no file-length rule
@@ -162,6 +168,9 @@ use_row() {
     go)
       FX_LINTER_CONFIG='.golangci.yml'
       FX_SETUP_FILE='golangci.yaml'
+      FX_ROUTED_FILE=''
+      FX_RULE_ID_RE=''
+      FX_ROUTED_SKIP=''
       FX_LENGTH_RULE='file-length-limit'
       FX_LINTER_COMMENT='#'
       FX_EXT='.go'
@@ -176,6 +185,9 @@ use_row() {
     python)
       FX_LINTER_CONFIG='.pylintrc'
       FX_SETUP_FILE=''
+      FX_ROUTED_FILE=''
+      FX_RULE_ID_RE=''
+      FX_ROUTED_SKIP=''
       FX_LENGTH_RULE=''
       FX_LINTER_COMMENT=';'
       FX_EXT='.py'
diff --git a/linter-driven-development/scripts/ldd-lint_test.sh b/linter-driven-development/scripts/ldd-lint_test.sh
index 1a1a7d8..c27e384 100644
--- a/linter-driven-development/scripts/ldd-lint_test.sh
+++ b/linter-driven-development/scripts/ldd-lint_test.sh
@@ -105,6 +105,12 @@ fill_dir() {
 #   FX_BLOCK_OPEN      the line that opens a block comment, "" when the
 #   FX_BLOCK_CLOSE     language has none, and the line that closes it
 #   FX_SKIP_FILES      source file names a directory count leaves out
+#   FX_ROUTED_FILE     the plugin's recommended config under setup/ for the
+#                      language, which enables every rule id the refactoring
+#                      routing table routes to a design rule; FX_RULE_ID_RE the
+#                      shape of the language's rule ids in that table, and
+#                      FX_ROUTED_SKIP the ids the config leaves out on purpose;
+#                      all "" when the plugin's table names no linter rule
 #   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
 #                      the file-length limit, and FX_LENGTH_RULE its rule; both
 #                      "" when the language's linter has no file-length rule
@@ -126,6 +132,9 @@ use_row() {
     go)
       FX_LINTER_CONFIG='.golangci.yml'
       FX_SETUP_FILE='golangci.yaml'
+      FX_ROUTED_FILE=''
+      FX_RULE_ID_RE=''
+      FX_ROUTED_SKIP=''
       FX_LENGTH_RULE='file-length-limit'
       FX_LINTER_COMMENT='#'
       FX_EXT='.go'
@@ -140,6 +149,9 @@ use_row() {
     python)
       FX_LINTER_CONFIG='.pylintrc'
       FX_SETUP_FILE=''
+      FX_ROUTED_FILE=''
+      FX_RULE_ID_RE=''
+      FX_ROUTED_SKIP=''
       FX_LENGTH_RULE=''
       FX_LINTER_COMMENT=';'
       FX_EXT='.py'
@@ -507,6 +519,29 @@ run_lint file-length
 expect_exit 0 && expect_not "held by " && expect_has "src/over$FX_EXT: $((MAX_LINES + 1)) code lines" && ok
 finish
 
+begin "the recommended config enables every rule the routing table routes to a design rule"
+if [[ -z "$FX_ROUTED_FILE" ]]; then skip "this plugin's routing table names no linter rule"; finish
+else
+  table=$(grep -l '^| Linter failure | Route |' "$(dirname "$LINT")"/../skills/refactoring/*.md | head -1)
+  missing=""; checked=0
+  while IFS= read -r id; do
+    case " $FX_ROUTED_SKIP " in *" $id "*) continue ;; esac
+    checked=$((checked + 1))
+    case "$id" in
+      *'*') re="(^|[^A-Za-z0-9/@-])${id%\*}" ;;
+      *)    re="(^|[^A-Za-z0-9/@-])${id}([^A-Za-z0-9/-]|\$)" ;;
+    esac
+    grep -qE -- "$re" "$(dirname "$LINT")/../setup/$FX_ROUTED_FILE" || missing="$missing $id"
+  done < <(awk -F'|' '
+      /^\| Linter failure \| Route \|/ { t = 1; next }
+      t && /^\|---/ { next }
+      t && /^\|/ { if ($3 ~ /rules\/R/) { c = $2; while (match(c, /`[^`]+`/)) { print substr(c, RSTART + 1, RLENGTH - 2); c = substr(c, RSTART + RLENGTH) } } next }
+      t { t = 0 }' "$table" | grep -E -- "$FX_RULE_ID_RE" | LC_ALL=C sort -u)
+  { [[ -n "$table" ]] && (( checked > 0 )) || bad "no routed rule id found in the routing table"; } \
+    && { [[ -z "$missing" ]] || bad "setup/$FX_ROUTED_FILE lacks:$missing"; } && [[ -z "$missing" ]] && ok
+  finish
+fi
+
 begin ".ldd-lint.yaml sets the limit when the linter holds none"
 printf 'file_max_lines: 100  # this repository\n' > "$REPO/.ldd-lint.yaml"
 write_src "src/a$FX_EXT" 101
diff --git a/linter-driven-development/scripts/ldd-scope_test.sh b/linter-driven-development/scripts/ldd-scope_test.sh
index 9f21328..07a9edd 100755
--- a/linter-driven-development/scripts/ldd-scope_test.sh
+++ b/linter-driven-development/scripts/ldd-scope_test.sh
@@ -117,6 +117,12 @@ mk_repo() { fx_write_marker "$REPO" fixture; fx_write_code; mk_docs; }
 #   FX_BLOCK_OPEN      the line that opens a block comment, "" when the
 #   FX_BLOCK_CLOSE     language has none, and the line that closes it
 #   FX_SKIP_FILES      source file names a directory count leaves out
+#   FX_ROUTED_FILE     the plugin's recommended config under setup/ for the
+#                      language, which enables every rule id the refactoring
+#                      routing table routes to a design rule; FX_RULE_ID_RE the
+#                      shape of the language's rule ids in that table, and
+#                      FX_ROUTED_SKIP the ids the config leaves out on purpose;
+#                      all "" when the plugin's table names no linter rule
 #   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
 #                      the file-length limit, and FX_LENGTH_RULE its rule; both
 #                      "" when the language's linter has no file-length rule
@@ -138,6 +144,9 @@ use_row() {
     go)
       FX_LINTER_CONFIG='.golangci.yml'
       FX_SETUP_FILE='golangci.yaml'
+      FX_ROUTED_FILE=''
+      FX_RULE_ID_RE=''
+      FX_ROUTED_SKIP=''
       FX_LENGTH_RULE='file-length-limit'
       FX_LINTER_COMMENT='#'
       FX_EXT='.go'
@@ -152,6 +161,9 @@ use_row() {
     python)
       FX_LINTER_CONFIG='.pylintrc'
       FX_SETUP_FILE=''
+      FX_ROUTED_FILE=''
+      FX_RULE_ID_RE=''
+      FX_ROUTED_SKIP=''
       FX_LENGTH_RULE=''
       FX_LINTER_COMMENT=';'
       FX_EXT='.py'
diff --git a/linter-driven-development/setup/eslint.config.ldd.mjs b/linter-driven-development/setup/eslint.config.ldd.mjs
index 3e47c93..4ccd360 100644
--- a/linter-driven-development/setup/eslint.config.ldd.mjs
+++ b/linter-driven-development/setup/eslint.config.ldd.mjs
@@ -3,18 +3,23 @@
 // design rules, at the limits the rules name. Each rule line says which rule its
 // failures feed. The plugin never writes this file into a repository: the
 // repository's owners copy it, or the parts they want, beside eslint.config.js
-// and spread it into the exported array:
+// and spread it before their own entries. Later entries win, so every limit the
+// repository's config already sets stays the repository's:
 //
 //   import ldd from './eslint.config.ldd.mjs'
-//   export default [...yourConfig, ...ldd]
+//   export default [...ldd, ...yourConfig]
 //
 // residue-exempt: an ESLint configuration names its plugins and rules on purpose.
 // It needs eslint-plugin-sonarjs, eslint-plugin-react, eslint-plugin-react-hooks,
 // eslint-plugin-promise, eslint-plugin-import and typescript-eslint; a repository
-// that does not use one of them leaves its rules out. Limits a repository already
-// sets stay the repository's: the linter is the authority for every threshold it
-// holds. Rules this file leaves out (style, imports, formatting) are the
-// repository's own choice.
+// that does not use one of them leaves its rules out. The @typescript-eslint rules
+// below need type information: the repository's config sets typescript-eslint's
+// parser with parserOptions.projectService for these files, or ESLint stops with
+// an error. Limits a repository already sets stay the repository's: the linter is
+// the authority for every threshold it holds. Rules this file leaves out (style,
+// imports, formatting) are the repository's own choice, and so is
+// no-restricted-syntax on import.meta.env outside the config module (R8): the
+// config module's path is the repository's.
 //
 // Adopt it on an existing codebase with ESLint's bulk suppressions: run
 // `npx eslint --suppress-all` once to record today's violations, so only new ones
@@ -54,9 +59,23 @@ export default [
       'sonarjs/no-duplicate-string': ['error', { threshold: 3 }],
       'sonarjs/max-union-size': ['error', { threshold: 4 }],
       'sonarjs/no-identical-functions': 'error',
+      'react/no-array-index-key': 'error',
+      'no-magic-numbers': ['error', {
+        ignore: [-1, 0, 1, 2],
+        ignoreArrayIndexes: true,
+        ignoreDefaultValues: true,
+        ignoreClassFieldInitialValues: true,
+        detectObjects: false,
+      }],
       // R2 self-validating types: parse at the boundary
       '@typescript-eslint/no-explicit-any': 'error',
       '@typescript-eslint/no-non-null-assertion': 'error',
+      '@typescript-eslint/no-unsafe-argument': 'error',
+      '@typescript-eslint/no-unsafe-assignment': 'error',
+      '@typescript-eslint/no-unsafe-call': 'error',
+      '@typescript-eslint/no-unsafe-member-access': 'error',
+      '@typescript-eslint/no-unsafe-return': 'error',
+      '@typescript-eslint/no-unnecessary-condition': 'error',
       // R5 vertical slice: one juicy module per file; counts code lines only
       'sonarjs/max-lines': ['error', { maximum: 450 }],
       'react/no-multi-comp': ['error', { ignoreStateless: false }],
@@ -64,6 +83,7 @@ export default [
       'import/no-mutable-exports': 'error',
       // R10 concurrency safety
       'react-hooks/exhaustive-deps': 'error',
+      'react-hooks/set-state-in-effect': 'error',
       '@typescript-eslint/no-floating-promises': 'error',
       '@typescript-eslint/no-misused-promises': 'error',
       'promise/catch-or-return': 'error',
@@ -86,6 +106,7 @@ export default [
       'sonarjs/no-duplicate-string': 'off',
       'sonarjs/no-nested-functions': 'off',
       'max-params': 'off',
+      'no-magic-numbers': 'off',
       'react/no-multi-comp': 'off',
       '@typescript-eslint/no-non-null-assertion': 'off',
     },
diff --git a/linter-driven-development/setup/golangci.yaml b/linter-driven-development/setup/golangci.yaml
index da5ef91..fd73147 100644
--- a/linter-driven-development/setup/golangci.yaml
+++ b/linter-driven-development/setup/golangci.yaml
@@ -11,7 +11,9 @@
 #
 # Adopt it on an existing codebase with the ratchet below: only issues in code
 # changed since the merge base with main fail, so old code is not a wall of
-# findings on day one. Remove the ratchet once the old findings are gone.
+# findings on day one. CI needs main in the clone for it (fetch-depth: 0 in
+# GitHub Actions). Remove the ratchet once the old findings are gone.
+# gocyclo stands for the routing table's "gocyclo / cyclop": enable one of the two.
 
 version: "2"
 
@@ -19,7 +21,9 @@ issues:
   new-from-merge-base: main
 
 linters:
-  default: none
+  # The standard set (errcheck, govet, ineffassign, staticcheck, unused) stays on;
+  # the linters below are added to it.
+  default: standard
   enable:
     - gocyclo           # R3 storifying: cyclomatic complexity
     - gocognit          # R3 storifying: cognitive complexity
diff --git a/linter-driven-development/setup/ruff.toml b/linter-driven-development/setup/ruff.toml
index 36ce201..1f91e7f 100644
--- a/linter-driven-development/setup/ruff.toml
+++ b/linter-driven-development/setup/ruff.toml
@@ -19,7 +19,9 @@
 #   git diff --name-only --diff-filter=d "$(git merge-base HEAD main)" -- '*.py' | xargs ruff check
 
 [lint]
-# PLR1702 (nested blocks) is a preview rule.
+# PLR1702 (nested blocks) is a preview rule. Preview mode also turns on preview
+# behavior of the stable rules a repository already selects; a repository that
+# does not want that drops these two lines and PLR1702.
 preview = true
 explicit-preview-rules = true
 extend-select = [
diff --git a/python-linter-driven-development/scripts/ldd-detect_test.sh b/python-linter-driven-development/scripts/ldd-detect_test.sh
index 6921c09..33300cb 100644
--- a/python-linter-driven-development/scripts/ldd-detect_test.sh
+++ b/python-linter-driven-development/scripts/ldd-detect_test.sh
@@ -141,6 +141,12 @@ questions_in_rules() {
 #   FX_BLOCK_OPEN      the line that opens a block comment, "" when the
 #   FX_BLOCK_CLOSE     language has none, and the line that closes it
 #   FX_SKIP_FILES      source file names a directory count leaves out
+#   FX_ROUTED_FILE     the plugin's recommended config under setup/ for the
+#                      language, which enables every rule id the refactoring
+#                      routing table routes to a design rule; FX_RULE_ID_RE the
+#                      shape of the language's rule ids in that table, and
+#                      FX_ROUTED_SKIP the ids the config leaves out on purpose;
+#                      all "" when the plugin's table names no linter rule
 #   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
 #                      the file-length limit, and FX_LENGTH_RULE its rule; both
 #                      "" when the language's linter has no file-length rule
@@ -160,6 +166,9 @@ FX_NATIVE="python"
 use_row() {
   FX_LINTER_CONFIG='pyproject.toml'
   FX_SETUP_FILE=''
+  FX_ROUTED_FILE='ruff.toml'
+  FX_RULE_ID_RE='^[A-Z]+[0-9]+$'
+  FX_ROUTED_SKIP=''
   FX_LENGTH_RULE=''
   FX_LINTER_COMMENT='#'
   FX_EXT='.py'
diff --git a/python-linter-driven-development/scripts/ldd-lint_test.sh b/python-linter-driven-development/scripts/ldd-lint_test.sh
index 6093bb0..1beed4a 100644
--- a/python-linter-driven-development/scripts/ldd-lint_test.sh
+++ b/python-linter-driven-development/scripts/ldd-lint_test.sh
@@ -105,6 +105,12 @@ fill_dir() {
 #   FX_BLOCK_OPEN      the line that opens a block comment, "" when the
 #   FX_BLOCK_CLOSE     language has none, and the line that closes it
 #   FX_SKIP_FILES      source file names a directory count leaves out
+#   FX_ROUTED_FILE     the plugin's recommended config under setup/ for the
+#                      language, which enables every rule id the refactoring
+#                      routing table routes to a design rule; FX_RULE_ID_RE the
+#                      shape of the language's rule ids in that table, and
+#                      FX_ROUTED_SKIP the ids the config leaves out on purpose;
+#                      all "" when the plugin's table names no linter rule
 #   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
 #                      the file-length limit, and FX_LENGTH_RULE its rule; both
 #                      "" when the language's linter has no file-length rule
@@ -124,6 +130,9 @@ FX_NATIVE="python"
 use_row() {
   FX_LINTER_CONFIG='pyproject.toml'
   FX_SETUP_FILE=''
+  FX_ROUTED_FILE='ruff.toml'
+  FX_RULE_ID_RE='^[A-Z]+[0-9]+$'
+  FX_ROUTED_SKIP=''
   FX_LENGTH_RULE=''
   FX_LINTER_COMMENT='#'
   FX_EXT='.py'
@@ -438,6 +447,29 @@ run_lint file-length
 expect_exit 0 && expect_not "held by " && expect_has "src/over$FX_EXT: $((MAX_LINES + 1)) code lines" && ok
 finish
 
+begin "the recommended config enables every rule the routing table routes to a design rule"
+if [[ -z "$FX_ROUTED_FILE" ]]; then skip "this plugin's routing table names no linter rule"; finish
+else
+  table=$(grep -l '^| Linter failure | Route |' "$(dirname "$LINT")"/../skills/refactoring/*.md | head -1)
+  missing=""; checked=0
+  while IFS= read -r id; do
+    case " $FX_ROUTED_SKIP " in *" $id "*) continue ;; esac
+    checked=$((checked + 1))
+    case "$id" in
+      *'*') re="(^|[^A-Za-z0-9/@-])${id%\*}" ;;
+      *)    re="(^|[^A-Za-z0-9/@-])${id}([^A-Za-z0-9/-]|\$)" ;;
+    esac
+    grep -qE -- "$re" "$(dirname "$LINT")/../setup/$FX_ROUTED_FILE" || missing="$missing $id"
+  done < <(awk -F'|' '
+      /^\| Linter failure \| Route \|/ { t = 1; next }
+      t && /^\|---/ { next }
+      t && /^\|/ { if ($3 ~ /rules\/R/) { c = $2; while (match(c, /`[^`]+`/)) { print substr(c, RSTART + 1, RLENGTH - 2); c = substr(c, RSTART + RLENGTH) } } next }
+      t { t = 0 }' "$table" | grep -E -- "$FX_RULE_ID_RE" | LC_ALL=C sort -u)
+  { [[ -n "$table" ]] && (( checked > 0 )) || bad "no routed rule id found in the routing table"; } \
+    && { [[ -z "$missing" ]] || bad "setup/$FX_ROUTED_FILE lacks:$missing"; } && [[ -z "$missing" ]] && ok
+  finish
+fi
+
 begin ".ldd-lint.yaml sets the limit when the linter holds none"
 printf 'file_max_lines: 100  # this repository\n' > "$REPO/.ldd-lint.yaml"
 write_src "src/a$FX_EXT" 101
diff --git a/python-linter-driven-development/scripts/ldd-scope_test.sh b/python-linter-driven-development/scripts/ldd-scope_test.sh
index 4a805ca..11ca084 100755
--- a/python-linter-driven-development/scripts/ldd-scope_test.sh
+++ b/python-linter-driven-development/scripts/ldd-scope_test.sh
@@ -117,6 +117,12 @@ mk_repo() { fx_write_marker "$REPO" fixture; fx_write_code; mk_docs; }
 #   FX_BLOCK_OPEN      the line that opens a block comment, "" when the
 #   FX_BLOCK_CLOSE     language has none, and the line that closes it
 #   FX_SKIP_FILES      source file names a directory count leaves out
+#   FX_ROUTED_FILE     the plugin's recommended config under setup/ for the
+#                      language, which enables every rule id the refactoring
+#                      routing table routes to a design rule; FX_RULE_ID_RE the
+#                      shape of the language's rule ids in that table, and
+#                      FX_ROUTED_SKIP the ids the config leaves out on purpose;
+#                      all "" when the plugin's table names no linter rule
 #   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
 #                      the file-length limit, and FX_LENGTH_RULE its rule; both
 #                      "" when the language's linter has no file-length rule
@@ -136,6 +142,9 @@ FX_NATIVE="python"
 use_row() {
   FX_LINTER_CONFIG='pyproject.toml'
   FX_SETUP_FILE=''
+  FX_ROUTED_FILE='ruff.toml'
+  FX_RULE_ID_RE='^[A-Z]+[0-9]+$'
+  FX_ROUTED_SKIP=''
   FX_LENGTH_RULE=''
   FX_LINTER_COMMENT='#'
   FX_EXT='.py'
diff --git a/python-linter-driven-development/setup/eslint.config.ldd.mjs b/python-linter-driven-development/setup/eslint.config.ldd.mjs
index 3e47c93..4ccd360 100644
--- a/python-linter-driven-development/setup/eslint.config.ldd.mjs
+++ b/python-linter-driven-development/setup/eslint.config.ldd.mjs
@@ -3,18 +3,23 @@
 // design rules, at the limits the rules name. Each rule line says which rule its
 // failures feed. The plugin never writes this file into a repository: the
 // repository's owners copy it, or the parts they want, beside eslint.config.js
-// and spread it into the exported array:
+// and spread it before their own entries. Later entries win, so every limit the
+// repository's config already sets stays the repository's:
 //
 //   import ldd from './eslint.config.ldd.mjs'
-//   export default [...yourConfig, ...ldd]
+//   export default [...ldd, ...yourConfig]
 //
 // residue-exempt: an ESLint configuration names its plugins and rules on purpose.
 // It needs eslint-plugin-sonarjs, eslint-plugin-react, eslint-plugin-react-hooks,
 // eslint-plugin-promise, eslint-plugin-import and typescript-eslint; a repository
-// that does not use one of them leaves its rules out. Limits a repository already
-// sets stay the repository's: the linter is the authority for every threshold it
-// holds. Rules this file leaves out (style, imports, formatting) are the
-// repository's own choice.
+// that does not use one of them leaves its rules out. The @typescript-eslint rules
+// below need type information: the repository's config sets typescript-eslint's
+// parser with parserOptions.projectService for these files, or ESLint stops with
+// an error. Limits a repository already sets stay the repository's: the linter is
+// the authority for every threshold it holds. Rules this file leaves out (style,
+// imports, formatting) are the repository's own choice, and so is
+// no-restricted-syntax on import.meta.env outside the config module (R8): the
+// config module's path is the repository's.
 //
 // Adopt it on an existing codebase with ESLint's bulk suppressions: run
 // `npx eslint --suppress-all` once to record today's violations, so only new ones
@@ -54,9 +59,23 @@ export default [
       'sonarjs/no-duplicate-string': ['error', { threshold: 3 }],
       'sonarjs/max-union-size': ['error', { threshold: 4 }],
       'sonarjs/no-identical-functions': 'error',
+      'react/no-array-index-key': 'error',
+      'no-magic-numbers': ['error', {
+        ignore: [-1, 0, 1, 2],
+        ignoreArrayIndexes: true,
+        ignoreDefaultValues: true,
+        ignoreClassFieldInitialValues: true,
+        detectObjects: false,
+      }],
       // R2 self-validating types: parse at the boundary
       '@typescript-eslint/no-explicit-any': 'error',
       '@typescript-eslint/no-non-null-assertion': 'error',
+      '@typescript-eslint/no-unsafe-argument': 'error',
+      '@typescript-eslint/no-unsafe-assignment': 'error',
+      '@typescript-eslint/no-unsafe-call': 'error',
+      '@typescript-eslint/no-unsafe-member-access': 'error',
+      '@typescript-eslint/no-unsafe-return': 'error',
+      '@typescript-eslint/no-unnecessary-condition': 'error',
       // R5 vertical slice: one juicy module per file; counts code lines only
       'sonarjs/max-lines': ['error', { maximum: 450 }],
       'react/no-multi-comp': ['error', { ignoreStateless: false }],
@@ -64,6 +83,7 @@ export default [
       'import/no-mutable-exports': 'error',
       // R10 concurrency safety
       'react-hooks/exhaustive-deps': 'error',
+      'react-hooks/set-state-in-effect': 'error',
       '@typescript-eslint/no-floating-promises': 'error',
       '@typescript-eslint/no-misused-promises': 'error',
       'promise/catch-or-return': 'error',
@@ -86,6 +106,7 @@ export default [
       'sonarjs/no-duplicate-string': 'off',
       'sonarjs/no-nested-functions': 'off',
       'max-params': 'off',
+      'no-magic-numbers': 'off',
       'react/no-multi-comp': 'off',
       '@typescript-eslint/no-non-null-assertion': 'off',
     },
diff --git a/python-linter-driven-development/setup/golangci.yaml b/python-linter-driven-development/setup/golangci.yaml
index da5ef91..fd73147 100644
--- a/python-linter-driven-development/setup/golangci.yaml
+++ b/python-linter-driven-development/setup/golangci.yaml
@@ -11,7 +11,9 @@
 #
 # Adopt it on an existing codebase with the ratchet below: only issues in code
 # changed since the merge base with main fail, so old code is not a wall of
-# findings on day one. Remove the ratchet once the old findings are gone.
+# findings on day one. CI needs main in the clone for it (fetch-depth: 0 in
+# GitHub Actions). Remove the ratchet once the old findings are gone.
+# gocyclo stands for the routing table's "gocyclo / cyclop": enable one of the two.
 
 version: "2"
 
@@ -19,7 +21,9 @@ issues:
   new-from-merge-base: main
 
 linters:
-  default: none
+  # The standard set (errcheck, govet, ineffassign, staticcheck, unused) stays on;
+  # the linters below are added to it.
+  default: standard
   enable:
     - gocyclo           # R3 storifying: cyclomatic complexity
     - gocognit          # R3 storifying: cognitive complexity
diff --git a/python-linter-driven-development/setup/ruff.toml b/python-linter-driven-development/setup/ruff.toml
index 36ce201..1f91e7f 100644
--- a/python-linter-driven-development/setup/ruff.toml
+++ b/python-linter-driven-development/setup/ruff.toml
@@ -19,7 +19,9 @@
 #   git diff --name-only --diff-filter=d "$(git merge-base HEAD main)" -- '*.py' | xargs ruff check
 
 [lint]
-# PLR1702 (nested blocks) is a preview rule.
+# PLR1702 (nested blocks) is a preview rule. Preview mode also turns on preview
+# behavior of the stable rules a repository already selects; a repository that
+# does not want that drops these two lines and PLR1702.
 preview = true
 explicit-preview-rules = true
 extend-select = [
diff --git a/ts-react-linter-driven-development/README.md b/ts-react-linter-driven-development/README.md
index 26f9bba..3117d92 100644
--- a/ts-react-linter-driven-development/README.md
+++ b/ts-react-linter-driven-development/README.md
@@ -146,7 +146,8 @@ adds a checker the repository does not use.
   in the plugin directory is a flat-config fragment with every rule the routing
   table routes to a design rule, at the limits the rules name. The plugin never
   writes it into your repository: copy it beside `eslint.config.js` and spread it
-  into the exported array. Limits your configuration already sets stay yours.
+  before your own entries, so every limit your configuration already sets stays
+  yours.
 - **What it does not review.** Accessibility beyond what `jsx-a11y` flags —
   contrast, heading order, focus management, live regions — is the repository's
   axe run, which this plugin does not replace. Error-boundary placement and
diff --git a/ts-react-linter-driven-development/scripts/ldd-detect_test.sh b/ts-react-linter-driven-development/scripts/ldd-detect_test.sh
index d3feca1..501eb6d 100644
--- a/ts-react-linter-driven-development/scripts/ldd-detect_test.sh
+++ b/ts-react-linter-driven-development/scripts/ldd-detect_test.sh
@@ -141,6 +141,12 @@ questions_in_rules() {
 #   FX_BLOCK_OPEN      the line that opens a block comment, "" when the
 #   FX_BLOCK_CLOSE     language has none, and the line that closes it
 #   FX_SKIP_FILES      source file names a directory count leaves out
+#   FX_ROUTED_FILE     the plugin's recommended config under setup/ for the
+#                      language, which enables every rule id the refactoring
+#                      routing table routes to a design rule; FX_RULE_ID_RE the
+#                      shape of the language's rule ids in that table, and
+#                      FX_ROUTED_SKIP the ids the config leaves out on purpose;
+#                      all "" when the plugin's table names no linter rule
 #   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
 #                      the file-length limit, and FX_LENGTH_RULE its rule; both
 #                      "" when the language's linter has no file-length rule
@@ -163,6 +169,11 @@ FX_NATIVE="typescript"
 use_row() {
   FX_LINTER_CONFIG='eslint.config.mjs'
   FX_SETUP_FILE='eslint.config.ldd.mjs'
+  FX_ROUTED_FILE='eslint.config.ldd.mjs'
+  FX_RULE_ID_RE='^(@[a-z-]+/)?[a-z-]+(/[a-z*-]+)?$'
+  # no-restricted-syntax needs the repository's config module path;
+  # package-size is the gap linter's
+  FX_ROUTED_SKIP='no-restricted-syntax package-size'
   FX_LENGTH_RULE='sonarjs/max-lines'
   FX_LINTER_COMMENT='//'
   FX_EXT='.ts'
diff --git a/ts-react-linter-driven-development/scripts/ldd-lint_test.sh b/ts-react-linter-driven-development/scripts/ldd-lint_test.sh
index 287993c..75c3cff 100644
--- a/ts-react-linter-driven-development/scripts/ldd-lint_test.sh
+++ b/ts-react-linter-driven-development/scripts/ldd-lint_test.sh
@@ -105,6 +105,12 @@ fill_dir() {
 #   FX_BLOCK_OPEN      the line that opens a block comment, "" when the
 #   FX_BLOCK_CLOSE     language has none, and the line that closes it
 #   FX_SKIP_FILES      source file names a directory count leaves out
+#   FX_ROUTED_FILE     the plugin's recommended config under setup/ for the
+#                      language, which enables every rule id the refactoring
+#                      routing table routes to a design rule; FX_RULE_ID_RE the
+#                      shape of the language's rule ids in that table, and
+#                      FX_ROUTED_SKIP the ids the config leaves out on purpose;
+#                      all "" when the plugin's table names no linter rule
 #   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
 #                      the file-length limit, and FX_LENGTH_RULE its rule; both
 #                      "" when the language's linter has no file-length rule
@@ -127,6 +133,11 @@ FX_NATIVE="typescript"
 use_row() {
   FX_LINTER_CONFIG='eslint.config.mjs'
   FX_SETUP_FILE='eslint.config.ldd.mjs'
+  FX_ROUTED_FILE='eslint.config.ldd.mjs'
+  FX_RULE_ID_RE='^(@[a-z-]+/)?[a-z-]+(/[a-z*-]+)?$'
+  # no-restricted-syntax needs the repository's config module path;
+  # package-size is the gap linter's
+  FX_ROUTED_SKIP='no-restricted-syntax package-size'
   FX_LENGTH_RULE='sonarjs/max-lines'
   FX_LINTER_COMMENT='//'
   FX_EXT='.ts'
@@ -442,6 +453,29 @@ run_lint file-length
 expect_exit 0 && expect_not "held by " && expect_has "src/over$FX_EXT: $((MAX_LINES + 1)) code lines" && ok
 finish
 
+begin "the recommended config enables every rule the routing table routes to a design rule"
+if [[ -z "$FX_ROUTED_FILE" ]]; then skip "this plugin's routing table names no linter rule"; finish
+else
+  table=$(grep -l '^| Linter failure | Route |' "$(dirname "$LINT")"/../skills/refactoring/*.md | head -1)
+  missing=""; checked=0
+  while IFS= read -r id; do
+    case " $FX_ROUTED_SKIP " in *" $id "*) continue ;; esac
+    checked=$((checked + 1))
+    case "$id" in
+      *'*') re="(^|[^A-Za-z0-9/@-])${id%\*}" ;;
+      *)    re="(^|[^A-Za-z0-9/@-])${id}([^A-Za-z0-9/-]|\$)" ;;
+    esac
+    grep -qE -- "$re" "$(dirname "$LINT")/../setup/$FX_ROUTED_FILE" || missing="$missing $id"
+  done < <(awk -F'|' '
+      /^\| Linter failure \| Route \|/ { t = 1; next }
+      t && /^\|---/ { next }
+      t && /^\|/ { if ($3 ~ /rules\/R/) { c = $2; while (match(c, /`[^`]+`/)) { print substr(c, RSTART + 1, RLENGTH - 2); c = substr(c, RSTART + RLENGTH) } } next }
+      t { t = 0 }' "$table" | grep -E -- "$FX_RULE_ID_RE" | LC_ALL=C sort -u)
+  { [[ -n "$table" ]] && (( checked > 0 )) || bad "no routed rule id found in the routing table"; } \
+    && { [[ -z "$missing" ]] || bad "setup/$FX_ROUTED_FILE lacks:$missing"; } && [[ -z "$missing" ]] && ok
+  finish
+fi
+
 begin ".ldd-lint.yaml sets the limit when the linter holds none"
 printf 'file_max_lines: 100  # this repository\n' > "$REPO/.ldd-lint.yaml"
 write_src "src/a$FX_EXT" 101
diff --git a/ts-react-linter-driven-development/scripts/ldd-scope_test.sh b/ts-react-linter-driven-development/scripts/ldd-scope_test.sh
index cac2339..b9ad613 100755
--- a/ts-react-linter-driven-development/scripts/ldd-scope_test.sh
+++ b/ts-react-linter-driven-development/scripts/ldd-scope_test.sh
@@ -117,6 +117,12 @@ mk_repo() { fx_write_marker "$REPO" fixture; fx_write_code; mk_docs; }
 #   FX_BLOCK_OPEN      the line that opens a block comment, "" when the
 #   FX_BLOCK_CLOSE     language has none, and the line that closes it
 #   FX_SKIP_FILES      source file names a directory count leaves out
+#   FX_ROUTED_FILE     the plugin's recommended config under setup/ for the
+#                      language, which enables every rule id the refactoring
+#                      routing table routes to a design rule; FX_RULE_ID_RE the
+#                      shape of the language's rule ids in that table, and
+#                      FX_ROUTED_SKIP the ids the config leaves out on purpose;
+#                      all "" when the plugin's table names no linter rule
 #   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
 #                      the file-length limit, and FX_LENGTH_RULE its rule; both
 #                      "" when the language's linter has no file-length rule
@@ -139,6 +145,11 @@ FX_NATIVE="typescript"
 use_row() {
   FX_LINTER_CONFIG='eslint.config.mjs'
   FX_SETUP_FILE='eslint.config.ldd.mjs'
+  FX_ROUTED_FILE='eslint.config.ldd.mjs'
+  FX_RULE_ID_RE='^(@[a-z-]+/)?[a-z-]+(/[a-z*-]+)?$'
+  # no-restricted-syntax needs the repository's config module path;
+  # package-size is the gap linter's
+  FX_ROUTED_SKIP='no-restricted-syntax package-size'
   FX_LENGTH_RULE='sonarjs/max-lines'
   FX_LINTER_COMMENT='//'
   FX_EXT='.ts'
diff --git a/ts-react-linter-driven-development/setup/eslint.config.ldd.mjs b/ts-react-linter-driven-development/setup/eslint.config.ldd.mjs
index 3e47c93..4ccd360 100644
--- a/ts-react-linter-driven-development/setup/eslint.config.ldd.mjs
+++ b/ts-react-linter-driven-development/setup/eslint.config.ldd.mjs
@@ -3,18 +3,23 @@
 // design rules, at the limits the rules name. Each rule line says which rule its
 // failures feed. The plugin never writes this file into a repository: the
 // repository's owners copy it, or the parts they want, beside eslint.config.js
-// and spread it into the exported array:
+// and spread it before their own entries. Later entries win, so every limit the
+// repository's config already sets stays the repository's:
 //
 //   import ldd from './eslint.config.ldd.mjs'
-//   export default [...yourConfig, ...ldd]
+//   export default [...ldd, ...yourConfig]
 //
 // residue-exempt: an ESLint configuration names its plugins and rules on purpose.
 // It needs eslint-plugin-sonarjs, eslint-plugin-react, eslint-plugin-react-hooks,
 // eslint-plugin-promise, eslint-plugin-import and typescript-eslint; a repository
-// that does not use one of them leaves its rules out. Limits a repository already
-// sets stay the repository's: the linter is the authority for every threshold it
-// holds. Rules this file leaves out (style, imports, formatting) are the
-// repository's own choice.
+// that does not use one of them leaves its rules out. The @typescript-eslint rules
+// below need type information: the repository's config sets typescript-eslint's
+// parser with parserOptions.projectService for these files, or ESLint stops with
+// an error. Limits a repository already sets stay the repository's: the linter is
+// the authority for every threshold it holds. Rules this file leaves out (style,
+// imports, formatting) are the repository's own choice, and so is
+// no-restricted-syntax on import.meta.env outside the config module (R8): the
+// config module's path is the repository's.
 //
 // Adopt it on an existing codebase with ESLint's bulk suppressions: run
 // `npx eslint --suppress-all` once to record today's violations, so only new ones
@@ -54,9 +59,23 @@ export default [
       'sonarjs/no-duplicate-string': ['error', { threshold: 3 }],
       'sonarjs/max-union-size': ['error', { threshold: 4 }],
       'sonarjs/no-identical-functions': 'error',
+      'react/no-array-index-key': 'error',
+      'no-magic-numbers': ['error', {
+        ignore: [-1, 0, 1, 2],
+        ignoreArrayIndexes: true,
+        ignoreDefaultValues: true,
+        ignoreClassFieldInitialValues: true,
+        detectObjects: false,
+      }],
       // R2 self-validating types: parse at the boundary
       '@typescript-eslint/no-explicit-any': 'error',
       '@typescript-eslint/no-non-null-assertion': 'error',
+      '@typescript-eslint/no-unsafe-argument': 'error',
+      '@typescript-eslint/no-unsafe-assignment': 'error',
+      '@typescript-eslint/no-unsafe-call': 'error',
+      '@typescript-eslint/no-unsafe-member-access': 'error',
+      '@typescript-eslint/no-unsafe-return': 'error',
+      '@typescript-eslint/no-unnecessary-condition': 'error',
       // R5 vertical slice: one juicy module per file; counts code lines only
       'sonarjs/max-lines': ['error', { maximum: 450 }],
       'react/no-multi-comp': ['error', { ignoreStateless: false }],
@@ -64,6 +83,7 @@ export default [
       'import/no-mutable-exports': 'error',
       // R10 concurrency safety
       'react-hooks/exhaustive-deps': 'error',
+      'react-hooks/set-state-in-effect': 'error',
       '@typescript-eslint/no-floating-promises': 'error',
       '@typescript-eslint/no-misused-promises': 'error',
       'promise/catch-or-return': 'error',
@@ -86,6 +106,7 @@ export default [
       'sonarjs/no-duplicate-string': 'off',
       'sonarjs/no-nested-functions': 'off',
       'max-params': 'off',
+      'no-magic-numbers': 'off',
       'react/no-multi-comp': 'off',
       '@typescript-eslint/no-non-null-assertion': 'off',
     },
diff --git a/ts-react-linter-driven-development/setup/golangci.yaml b/ts-react-linter-driven-development/setup/golangci.yaml
index da5ef91..fd73147 100644
--- a/ts-react-linter-driven-development/setup/golangci.yaml
+++ b/ts-react-linter-driven-development/setup/golangci.yaml
@@ -11,7 +11,9 @@
 #
 # Adopt it on an existing codebase with the ratchet below: only issues in code
 # changed since the merge base with main fail, so old code is not a wall of
-# findings on day one. Remove the ratchet once the old findings are gone.
+# findings on day one. CI needs main in the clone for it (fetch-depth: 0 in
+# GitHub Actions). Remove the ratchet once the old findings are gone.
+# gocyclo stands for the routing table's "gocyclo / cyclop": enable one of the two.
 
 version: "2"
 
@@ -19,7 +21,9 @@ issues:
   new-from-merge-base: main
 
 linters:
-  default: none
+  # The standard set (errcheck, govet, ineffassign, staticcheck, unused) stays on;
+  # the linters below are added to it.
+  default: standard
   enable:
     - gocyclo           # R3 storifying: cyclomatic complexity
     - gocognit          # R3 storifying: cognitive complexity
diff --git a/ts-react-linter-driven-development/setup/ruff.toml b/ts-react-linter-driven-development/setup/ruff.toml
index 36ce201..1f91e7f 100644
--- a/ts-react-linter-driven-development/setup/ruff.toml
+++ b/ts-react-linter-driven-development/setup/ruff.toml
@@ -19,7 +19,9 @@
 #   git diff --name-only --diff-filter=d "$(git merge-base HEAD main)" -- '*.py' | xargs ruff check
 
 [lint]
-# PLR1702 (nested blocks) is a preview rule.
+# PLR1702 (nested blocks) is a preview rule. Preview mode also turns on preview
+# behavior of the stable rules a repository already selects; a repository that
+# does not want that drops these two lines and PLR1702.
 preview = true
 explicit-preview-rules = true
 extend-select = [

From c76049e00168bb5b8cb86fdba164847f57171335 Mon Sep 17 00:00:00 2001
From: Dan Mordechay <dan.mordechay@weka.io>
Date: Tue, 20 Oct 2026 21:37:50 +0300
Subject: [PATCH 3/3] setup: R3's limits in the configs, the imported fragment
 counts as held

- eslint.config.ldd.mjs: sonarjs/max-lines-per-function 50 and
  sonarjs/nested-control-flow 2, the limits R3 names (more than 50 lines or
  more than 2 nesting levels). They were 200 and 4.
- ruff.toml: max-nested-blocks 2, R3's nesting limit. It was 5.
- ruff.toml: the changed-files command passes NUL-delimited paths and
  exits 0 without running ruff when no Python file changed. Before, GNU
  xargs ran ruff once with no paths, and ruff checked the whole repository.
- The gap linter treats eslint.config.ldd.mjs at the repository root as a
  linter config. A repository that keeps the fragment as its own file and
  imports it hands file length to ESLint. Before, the gap linter still
  measured with its own default. A matrix case covers it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 core/includes/scripts/ldd-lint-langs.sh       |  4 +++-
 core/scripts/ldd-lint_test.sh                 | 10 ++++++++++
 core/setup/eslint.config.ldd.mjs              |  5 +++--
 core/setup/ruff.toml                          |  7 +++++--
 .../scripts/ldd-detect_test.sh                |  4 ++++
 .../scripts/ldd-lint.sh                       |  4 +++-
 .../scripts/ldd-lint_test.sh                  | 18 +++++++++++++++++-
 .../scripts/ldd-scope_test.sh                 |  4 ++++
 .../setup/eslint.config.ldd.mjs               |  5 +++--
 go-linter-driven-development/setup/ruff.toml  |  7 +++++--
 lang/generic/scripts/ldd-fixture.sh           |  5 +++++
 lang/go/scripts/ldd-fixture.sh                |  4 ++++
 lang/python/scripts/ldd-fixture.sh            |  4 ++++
 lang/ts-react/scripts/ldd-fixture.sh          |  4 ++++
 .../scripts/ldd-detect_test.sh                |  5 +++++
 linter-driven-development/scripts/ldd-lint.sh |  4 +++-
 .../scripts/ldd-lint_test.sh                  | 19 ++++++++++++++++++-
 .../scripts/ldd-scope_test.sh                 |  5 +++++
 .../setup/eslint.config.ldd.mjs               |  5 +++--
 linter-driven-development/setup/ruff.toml     |  7 +++++--
 .../scripts/ldd-detect_test.sh                |  4 ++++
 .../scripts/ldd-lint.sh                       |  4 +++-
 .../scripts/ldd-lint_test.sh                  | 18 +++++++++++++++++-
 .../scripts/ldd-scope_test.sh                 |  4 ++++
 .../setup/eslint.config.ldd.mjs               |  5 +++--
 .../setup/ruff.toml                           |  7 +++++--
 .../scripts/ldd-detect_test.sh                |  4 ++++
 .../scripts/ldd-lint.sh                       |  4 +++-
 .../scripts/ldd-lint_test.sh                  | 18 +++++++++++++++++-
 .../scripts/ldd-scope_test.sh                 |  4 ++++
 .../setup/eslint.config.ldd.mjs               |  5 +++--
 .../setup/ruff.toml                           |  7 +++++--
 32 files changed, 185 insertions(+), 29 deletions(-)

diff --git a/core/includes/scripts/ldd-lint-langs.sh b/core/includes/scripts/ldd-lint-langs.sh
index 54c3325..ea3e885 100644
--- a/core/includes/scripts/ldd-lint-langs.sh
+++ b/core/includes/scripts/ldd-lint-langs.sh
@@ -118,8 +118,10 @@ lint_file_length_rule() {
       f=$(_lint_names 'file-length-limit' .golangci.yaml .golangci.yml .golangci.toml .golangci.json) \
         && printf 'revive file-length-limit in %s' "$f" ;;
     typescript|javascript)
+      # eslint.config.ldd.mjs is the plugin's recommended fragment: a repository
+      # that adopts it keeps it beside eslint.config.js and imports it.
       local configs=(eslint.config.js eslint.config.mjs eslint.config.cjs eslint.config.ts eslint.config.mts eslint.config.cts
-                     .eslintrc .eslintrc.js .eslintrc.cjs .eslintrc.json .eslintrc.yml .eslintrc.yaml)
+                     eslint.config.ldd.mjs .eslintrc .eslintrc.js .eslintrc.cjs .eslintrc.json .eslintrc.yml .eslintrc.yaml)
       if f=$(_lint_names 'sonarjs/max-lines([^-a-zA-Z]|$)' "${configs[@]}"); then
         printf 'sonarjs/max-lines in %s' "$f"
       elif f=$(_lint_names '(^|[^-/a-zA-Z])max-lines([^-a-zA-Z]|$)' "${configs[@]}"); then
diff --git a/core/scripts/ldd-lint_test.sh b/core/scripts/ldd-lint_test.sh
index d63f497..cce23a0 100644
--- a/core/scripts/ldd-lint_test.sh
+++ b/core/scripts/ldd-lint_test.sh
@@ -212,6 +212,16 @@ else
   finish
 fi
 
+begin "the recommended fragment, kept as its own file and imported, hands file length to the linter"
+if [[ -z "$FX_ADOPTED_CONFIG" ]]; then skip "this language's setup is copied into the linter's own config"; finish
+else
+  cp "$(dirname "$LINT")/../setup/$FX_ADOPTED_CONFIG" "$REPO/$FX_ADOPTED_CONFIG"
+  write_src "src/over$FX_EXT" $((MAX_LINES + 50))
+  run_lint file-length
+  expect_exit 0 && expect_has "held by " && expect_has "in $FX_ADOPTED_CONFIG" && expect_no_finding && ok
+  finish
+fi
+
 begin ".ldd-lint.yaml sets the limit when the linter holds none"
 printf 'file_max_lines: 100  # this repository\n' > "$REPO/.ldd-lint.yaml"
 write_src "src/a$FX_EXT" 101
diff --git a/core/setup/eslint.config.ldd.mjs b/core/setup/eslint.config.ldd.mjs
index 936e99a..d679c76 100644
--- a/core/setup/eslint.config.ldd.mjs
+++ b/core/setup/eslint.config.ldd.mjs
@@ -48,8 +48,9 @@ export default [
       'sonarjs/cognitive-complexity': ['error', 15],
       'sonarjs/cyclomatic-complexity': ['error', { threshold: 10 }],
       'sonarjs/expression-complexity': ['error', { max: 5 }],
-      'sonarjs/max-lines-per-function': ['error', { maximum: 200 }],
-      'sonarjs/nested-control-flow': ['error', { maximumNestingLevel: 4 }],
+      // R3's limits: more than 50 lines or more than 2 nesting levels
+      'sonarjs/max-lines-per-function': ['error', { maximum: 50 }],
+      'sonarjs/nested-control-flow': ['error', { maximumNestingLevel: 2 }],
       'sonarjs/no-nested-conditional': 'error',
       'sonarjs/no-nested-functions': 'error',
       'sonarjs/elseif-without-else': 'error',
diff --git a/core/setup/ruff.toml b/core/setup/ruff.toml
index b4ee32e..bca37e5 100644
--- a/core/setup/ruff.toml
+++ b/core/setup/ruff.toml
@@ -16,7 +16,10 @@
 # Adopt it on an existing codebase one change at a time: run ruff on the files
 # changed since the merge base with main, so old code is not a wall of
 # findings on day one:
-#   git diff --name-only --diff-filter=d "$(git merge-base HEAD main)" -- '*.py' | xargs ruff check
+#   git diff -z --name-only --diff-filter=d "$(git merge-base HEAD main)" -- '*.py' \
+#     | xargs -0 sh -c '[ "$#" -eq 0 ] || ruff check "$@"' sh
+# The sh guard keeps an empty change list from checking the whole repository,
+# and -z with -0 keeps a path with spaces whole.
 
 [lint]
 # PLR1702 (nested blocks) is a preview rule. Preview mode also turns on preview
@@ -47,7 +50,7 @@ max-args = 4          # self and cls are not counted
 max-branches = 12
 max-returns = 6
 max-statements = 50
-max-nested-blocks = 5
+max-nested-blocks = 2  # R3: more than 2 nesting levels
 
 [lint.per-file-ignores]
 # Tests repeat literals and take many fixtures by design.
diff --git a/go-linter-driven-development/scripts/ldd-detect_test.sh b/go-linter-driven-development/scripts/ldd-detect_test.sh
index 3068f63..7d7a85e 100644
--- a/go-linter-driven-development/scripts/ldd-detect_test.sh
+++ b/go-linter-driven-development/scripts/ldd-detect_test.sh
@@ -147,6 +147,9 @@ questions_in_rules() {
 #                      shape of the language's rule ids in that table, and
 #                      FX_ROUTED_SKIP the ids the config leaves out on purpose;
 #                      all "" when the plugin's table names no linter rule
+#   FX_ADOPTED_CONFIG  the name under which a repository keeps the plugin's
+#                      recommended config as its own file and imports it; ""
+#                      when the setup is copied into the linter's own config
 #   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
 #                      the file-length limit, and FX_LENGTH_RULE its rule; both
 #                      "" when the language's linter has no file-length rule
@@ -166,6 +169,7 @@ FX_NATIVE="go"
 use_row() {
   FX_LINTER_CONFIG='.golangci.yaml'
   FX_SETUP_FILE='golangci.yaml'
+  FX_ADOPTED_CONFIG=''
   FX_ROUTED_FILE='golangci.yaml'
   FX_RULE_ID_RE='^[a-z][a-z0-9-]*$'
   # cyclop is the alternative to gocyclo; package-size is the gap linter's
diff --git a/go-linter-driven-development/scripts/ldd-lint.sh b/go-linter-driven-development/scripts/ldd-lint.sh
index 9768869..8658fc0 100755
--- a/go-linter-driven-development/scripts/ldd-lint.sh
+++ b/go-linter-driven-development/scripts/ldd-lint.sh
@@ -319,8 +319,10 @@ lint_file_length_rule() {
       f=$(_lint_names 'file-length-limit' .golangci.yaml .golangci.yml .golangci.toml .golangci.json) \
         && printf 'revive file-length-limit in %s' "$f" ;;
     typescript|javascript)
+      # eslint.config.ldd.mjs is the plugin's recommended fragment: a repository
+      # that adopts it keeps it beside eslint.config.js and imports it.
       local configs=(eslint.config.js eslint.config.mjs eslint.config.cjs eslint.config.ts eslint.config.mts eslint.config.cts
-                     .eslintrc .eslintrc.js .eslintrc.cjs .eslintrc.json .eslintrc.yml .eslintrc.yaml)
+                     eslint.config.ldd.mjs .eslintrc .eslintrc.js .eslintrc.cjs .eslintrc.json .eslintrc.yml .eslintrc.yaml)
       if f=$(_lint_names 'sonarjs/max-lines([^-a-zA-Z]|$)' "${configs[@]}"); then
         printf 'sonarjs/max-lines in %s' "$f"
       elif f=$(_lint_names '(^|[^-/a-zA-Z])max-lines([^-a-zA-Z]|$)' "${configs[@]}"); then
diff --git a/go-linter-driven-development/scripts/ldd-lint_test.sh b/go-linter-driven-development/scripts/ldd-lint_test.sh
index b66dd24..eb3a00e 100644
--- a/go-linter-driven-development/scripts/ldd-lint_test.sh
+++ b/go-linter-driven-development/scripts/ldd-lint_test.sh
@@ -111,6 +111,9 @@ fill_dir() {
 #                      shape of the language's rule ids in that table, and
 #                      FX_ROUTED_SKIP the ids the config leaves out on purpose;
 #                      all "" when the plugin's table names no linter rule
+#   FX_ADOPTED_CONFIG  the name under which a repository keeps the plugin's
+#                      recommended config as its own file and imports it; ""
+#                      when the setup is copied into the linter's own config
 #   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
 #                      the file-length limit, and FX_LENGTH_RULE its rule; both
 #                      "" when the language's linter has no file-length rule
@@ -130,6 +133,7 @@ FX_NATIVE="go"
 use_row() {
   FX_LINTER_CONFIG='.golangci.yaml'
   FX_SETUP_FILE='golangci.yaml'
+  FX_ADOPTED_CONFIG=''
   FX_ROUTED_FILE='golangci.yaml'
   FX_RULE_ID_RE='^[a-z][a-z0-9-]*$'
   # cyclop is the alternative to gocyclo; package-size is the gap linter's
@@ -315,8 +319,10 @@ lint_file_length_rule() {
       f=$(_lint_names 'file-length-limit' .golangci.yaml .golangci.yml .golangci.toml .golangci.json) \
         && printf 'revive file-length-limit in %s' "$f" ;;
     typescript|javascript)
+      # eslint.config.ldd.mjs is the plugin's recommended fragment: a repository
+      # that adopts it keeps it beside eslint.config.js and imports it.
       local configs=(eslint.config.js eslint.config.mjs eslint.config.cjs eslint.config.ts eslint.config.mts eslint.config.cts
-                     .eslintrc .eslintrc.js .eslintrc.cjs .eslintrc.json .eslintrc.yml .eslintrc.yaml)
+                     eslint.config.ldd.mjs .eslintrc .eslintrc.js .eslintrc.cjs .eslintrc.json .eslintrc.yml .eslintrc.yaml)
       if f=$(_lint_names 'sonarjs/max-lines([^-a-zA-Z]|$)' "${configs[@]}"); then
         printf 'sonarjs/max-lines in %s' "$f"
       elif f=$(_lint_names '(^|[^-/a-zA-Z])max-lines([^-a-zA-Z]|$)' "${configs[@]}"); then
@@ -477,6 +483,16 @@ else
   finish
 fi
 
+begin "the recommended fragment, kept as its own file and imported, hands file length to the linter"
+if [[ -z "$FX_ADOPTED_CONFIG" ]]; then skip "this language's setup is copied into the linter's own config"; finish
+else
+  cp "$(dirname "$LINT")/../setup/$FX_ADOPTED_CONFIG" "$REPO/$FX_ADOPTED_CONFIG"
+  write_src "src/over$FX_EXT" $((MAX_LINES + 50))
+  run_lint file-length
+  expect_exit 0 && expect_has "held by " && expect_has "in $FX_ADOPTED_CONFIG" && expect_no_finding && ok
+  finish
+fi
+
 begin ".ldd-lint.yaml sets the limit when the linter holds none"
 printf 'file_max_lines: 100  # this repository\n' > "$REPO/.ldd-lint.yaml"
 write_src "src/a$FX_EXT" 101
diff --git a/go-linter-driven-development/scripts/ldd-scope_test.sh b/go-linter-driven-development/scripts/ldd-scope_test.sh
index eaebc6e..fe5d9fc 100755
--- a/go-linter-driven-development/scripts/ldd-scope_test.sh
+++ b/go-linter-driven-development/scripts/ldd-scope_test.sh
@@ -123,6 +123,9 @@ mk_repo() { fx_write_marker "$REPO" fixture; fx_write_code; mk_docs; }
 #                      shape of the language's rule ids in that table, and
 #                      FX_ROUTED_SKIP the ids the config leaves out on purpose;
 #                      all "" when the plugin's table names no linter rule
+#   FX_ADOPTED_CONFIG  the name under which a repository keeps the plugin's
+#                      recommended config as its own file and imports it; ""
+#                      when the setup is copied into the linter's own config
 #   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
 #                      the file-length limit, and FX_LENGTH_RULE its rule; both
 #                      "" when the language's linter has no file-length rule
@@ -142,6 +145,7 @@ FX_NATIVE="go"
 use_row() {
   FX_LINTER_CONFIG='.golangci.yaml'
   FX_SETUP_FILE='golangci.yaml'
+  FX_ADOPTED_CONFIG=''
   FX_ROUTED_FILE='golangci.yaml'
   FX_RULE_ID_RE='^[a-z][a-z0-9-]*$'
   # cyclop is the alternative to gocyclo; package-size is the gap linter's
diff --git a/go-linter-driven-development/setup/eslint.config.ldd.mjs b/go-linter-driven-development/setup/eslint.config.ldd.mjs
index 4ccd360..85da438 100644
--- a/go-linter-driven-development/setup/eslint.config.ldd.mjs
+++ b/go-linter-driven-development/setup/eslint.config.ldd.mjs
@@ -48,8 +48,9 @@ export default [
       'sonarjs/cognitive-complexity': ['error', 15],
       'sonarjs/cyclomatic-complexity': ['error', { threshold: 10 }],
       'sonarjs/expression-complexity': ['error', { max: 5 }],
-      'sonarjs/max-lines-per-function': ['error', { maximum: 200 }],
-      'sonarjs/nested-control-flow': ['error', { maximumNestingLevel: 4 }],
+      // R3's limits: more than 50 lines or more than 2 nesting levels
+      'sonarjs/max-lines-per-function': ['error', { maximum: 50 }],
+      'sonarjs/nested-control-flow': ['error', { maximumNestingLevel: 2 }],
       'sonarjs/no-nested-conditional': 'error',
       'sonarjs/no-nested-functions': 'error',
       'sonarjs/elseif-without-else': 'error',
diff --git a/go-linter-driven-development/setup/ruff.toml b/go-linter-driven-development/setup/ruff.toml
index 1f91e7f..03571ca 100644
--- a/go-linter-driven-development/setup/ruff.toml
+++ b/go-linter-driven-development/setup/ruff.toml
@@ -16,7 +16,10 @@
 # Adopt it on an existing codebase one change at a time: run ruff on the files
 # changed since the merge base with main, so old code is not a wall of
 # findings on day one:
-#   git diff --name-only --diff-filter=d "$(git merge-base HEAD main)" -- '*.py' | xargs ruff check
+#   git diff -z --name-only --diff-filter=d "$(git merge-base HEAD main)" -- '*.py' \
+#     | xargs -0 sh -c '[ "$#" -eq 0 ] || ruff check "$@"' sh
+# The sh guard keeps an empty change list from checking the whole repository,
+# and -z with -0 keeps a path with spaces whole.
 
 [lint]
 # PLR1702 (nested blocks) is a preview rule. Preview mode also turns on preview
@@ -47,7 +50,7 @@ max-args = 4          # self and cls are not counted
 max-branches = 12
 max-returns = 6
 max-statements = 50
-max-nested-blocks = 5
+max-nested-blocks = 2  # R3: more than 2 nesting levels
 
 [lint.per-file-ignores]
 # Tests repeat literals and take many fixtures by design.
diff --git a/lang/generic/scripts/ldd-fixture.sh b/lang/generic/scripts/ldd-fixture.sh
index 1dab74d..055ea51 100644
--- a/lang/generic/scripts/ldd-fixture.sh
+++ b/lang/generic/scripts/ldd-fixture.sh
@@ -24,6 +24,9 @@
 #                      shape of the language's rule ids in that table, and
 #                      FX_ROUTED_SKIP the ids the config leaves out on purpose;
 #                      all "" when the plugin's table names no linter rule
+#   FX_ADOPTED_CONFIG  the name under which a repository keeps the plugin's
+#                      recommended config as its own file and imports it; ""
+#                      when the setup is copied into the linter's own config
 #   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
 #                      the file-length limit, and FX_LENGTH_RULE its rule; both
 #                      "" when the language's linter has no file-length rule
@@ -45,6 +48,7 @@ use_row() {
     go)
       FX_LINTER_CONFIG='.golangci.yml'
       FX_SETUP_FILE='golangci.yaml'
+      FX_ADOPTED_CONFIG=''
       FX_ROUTED_FILE=''
       FX_RULE_ID_RE=''
       FX_ROUTED_SKIP=''
@@ -62,6 +66,7 @@ use_row() {
     python)
       FX_LINTER_CONFIG='.pylintrc'
       FX_SETUP_FILE=''
+      FX_ADOPTED_CONFIG=''
       FX_ROUTED_FILE=''
       FX_RULE_ID_RE=''
       FX_ROUTED_SKIP=''
diff --git a/lang/go/scripts/ldd-fixture.sh b/lang/go/scripts/ldd-fixture.sh
index 472d464..10f15e3 100644
--- a/lang/go/scripts/ldd-fixture.sh
+++ b/lang/go/scripts/ldd-fixture.sh
@@ -24,6 +24,9 @@
 #                      shape of the language's rule ids in that table, and
 #                      FX_ROUTED_SKIP the ids the config leaves out on purpose;
 #                      all "" when the plugin's table names no linter rule
+#   FX_ADOPTED_CONFIG  the name under which a repository keeps the plugin's
+#                      recommended config as its own file and imports it; ""
+#                      when the setup is copied into the linter's own config
 #   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
 #                      the file-length limit, and FX_LENGTH_RULE its rule; both
 #                      "" when the language's linter has no file-length rule
@@ -43,6 +46,7 @@ FX_NATIVE="go"
 use_row() {
   FX_LINTER_CONFIG='.golangci.yaml'
   FX_SETUP_FILE='golangci.yaml'
+  FX_ADOPTED_CONFIG=''
   FX_ROUTED_FILE='golangci.yaml'
   FX_RULE_ID_RE='^[a-z][a-z0-9-]*$'
   # cyclop is the alternative to gocyclo; package-size is the gap linter's
diff --git a/lang/python/scripts/ldd-fixture.sh b/lang/python/scripts/ldd-fixture.sh
index cdcde9b..5645170 100644
--- a/lang/python/scripts/ldd-fixture.sh
+++ b/lang/python/scripts/ldd-fixture.sh
@@ -24,6 +24,9 @@
 #                      shape of the language's rule ids in that table, and
 #                      FX_ROUTED_SKIP the ids the config leaves out on purpose;
 #                      all "" when the plugin's table names no linter rule
+#   FX_ADOPTED_CONFIG  the name under which a repository keeps the plugin's
+#                      recommended config as its own file and imports it; ""
+#                      when the setup is copied into the linter's own config
 #   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
 #                      the file-length limit, and FX_LENGTH_RULE its rule; both
 #                      "" when the language's linter has no file-length rule
@@ -43,6 +46,7 @@ FX_NATIVE="python"
 use_row() {
   FX_LINTER_CONFIG='pyproject.toml'
   FX_SETUP_FILE=''
+  FX_ADOPTED_CONFIG=''
   FX_ROUTED_FILE='ruff.toml'
   FX_RULE_ID_RE='^[A-Z]+[0-9]+$'
   FX_ROUTED_SKIP=''
diff --git a/lang/ts-react/scripts/ldd-fixture.sh b/lang/ts-react/scripts/ldd-fixture.sh
index 334600e..3d57f0c 100644
--- a/lang/ts-react/scripts/ldd-fixture.sh
+++ b/lang/ts-react/scripts/ldd-fixture.sh
@@ -24,6 +24,9 @@
 #                      shape of the language's rule ids in that table, and
 #                      FX_ROUTED_SKIP the ids the config leaves out on purpose;
 #                      all "" when the plugin's table names no linter rule
+#   FX_ADOPTED_CONFIG  the name under which a repository keeps the plugin's
+#                      recommended config as its own file and imports it; ""
+#                      when the setup is copied into the linter's own config
 #   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
 #                      the file-length limit, and FX_LENGTH_RULE its rule; both
 #                      "" when the language's linter has no file-length rule
@@ -46,6 +49,7 @@ FX_NATIVE="typescript"
 use_row() {
   FX_LINTER_CONFIG='eslint.config.mjs'
   FX_SETUP_FILE='eslint.config.ldd.mjs'
+  FX_ADOPTED_CONFIG='eslint.config.ldd.mjs'
   FX_ROUTED_FILE='eslint.config.ldd.mjs'
   FX_RULE_ID_RE='^(@[a-z-]+/)?[a-z-]+(/[a-z*-]+)?$'
   # no-restricted-syntax needs the repository's config module path;
diff --git a/linter-driven-development/scripts/ldd-detect_test.sh b/linter-driven-development/scripts/ldd-detect_test.sh
index 9a709b5..fe0cfc7 100644
--- a/linter-driven-development/scripts/ldd-detect_test.sh
+++ b/linter-driven-development/scripts/ldd-detect_test.sh
@@ -147,6 +147,9 @@ questions_in_rules() {
 #                      shape of the language's rule ids in that table, and
 #                      FX_ROUTED_SKIP the ids the config leaves out on purpose;
 #                      all "" when the plugin's table names no linter rule
+#   FX_ADOPTED_CONFIG  the name under which a repository keeps the plugin's
+#                      recommended config as its own file and imports it; ""
+#                      when the setup is copied into the linter's own config
 #   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
 #                      the file-length limit, and FX_LENGTH_RULE its rule; both
 #                      "" when the language's linter has no file-length rule
@@ -168,6 +171,7 @@ use_row() {
     go)
       FX_LINTER_CONFIG='.golangci.yml'
       FX_SETUP_FILE='golangci.yaml'
+      FX_ADOPTED_CONFIG=''
       FX_ROUTED_FILE=''
       FX_RULE_ID_RE=''
       FX_ROUTED_SKIP=''
@@ -185,6 +189,7 @@ use_row() {
     python)
       FX_LINTER_CONFIG='.pylintrc'
       FX_SETUP_FILE=''
+      FX_ADOPTED_CONFIG=''
       FX_ROUTED_FILE=''
       FX_RULE_ID_RE=''
       FX_ROUTED_SKIP=''
diff --git a/linter-driven-development/scripts/ldd-lint.sh b/linter-driven-development/scripts/ldd-lint.sh
index 98ea9af..a8d34d6 100755
--- a/linter-driven-development/scripts/ldd-lint.sh
+++ b/linter-driven-development/scripts/ldd-lint.sh
@@ -435,8 +435,10 @@ lint_file_length_rule() {
       f=$(_lint_names 'file-length-limit' .golangci.yaml .golangci.yml .golangci.toml .golangci.json) \
         && printf 'revive file-length-limit in %s' "$f" ;;
     typescript|javascript)
+      # eslint.config.ldd.mjs is the plugin's recommended fragment: a repository
+      # that adopts it keeps it beside eslint.config.js and imports it.
       local configs=(eslint.config.js eslint.config.mjs eslint.config.cjs eslint.config.ts eslint.config.mts eslint.config.cts
-                     .eslintrc .eslintrc.js .eslintrc.cjs .eslintrc.json .eslintrc.yml .eslintrc.yaml)
+                     eslint.config.ldd.mjs .eslintrc .eslintrc.js .eslintrc.cjs .eslintrc.json .eslintrc.yml .eslintrc.yaml)
       if f=$(_lint_names 'sonarjs/max-lines([^-a-zA-Z]|$)' "${configs[@]}"); then
         printf 'sonarjs/max-lines in %s' "$f"
       elif f=$(_lint_names '(^|[^-/a-zA-Z])max-lines([^-a-zA-Z]|$)' "${configs[@]}"); then
diff --git a/linter-driven-development/scripts/ldd-lint_test.sh b/linter-driven-development/scripts/ldd-lint_test.sh
index c27e384..99f31f9 100644
--- a/linter-driven-development/scripts/ldd-lint_test.sh
+++ b/linter-driven-development/scripts/ldd-lint_test.sh
@@ -111,6 +111,9 @@ fill_dir() {
 #                      shape of the language's rule ids in that table, and
 #                      FX_ROUTED_SKIP the ids the config leaves out on purpose;
 #                      all "" when the plugin's table names no linter rule
+#   FX_ADOPTED_CONFIG  the name under which a repository keeps the plugin's
+#                      recommended config as its own file and imports it; ""
+#                      when the setup is copied into the linter's own config
 #   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
 #                      the file-length limit, and FX_LENGTH_RULE its rule; both
 #                      "" when the language's linter has no file-length rule
@@ -132,6 +135,7 @@ use_row() {
     go)
       FX_LINTER_CONFIG='.golangci.yml'
       FX_SETUP_FILE='golangci.yaml'
+      FX_ADOPTED_CONFIG=''
       FX_ROUTED_FILE=''
       FX_RULE_ID_RE=''
       FX_ROUTED_SKIP=''
@@ -149,6 +153,7 @@ use_row() {
     python)
       FX_LINTER_CONFIG='.pylintrc'
       FX_SETUP_FILE=''
+      FX_ADOPTED_CONFIG=''
       FX_ROUTED_FILE=''
       FX_RULE_ID_RE=''
       FX_ROUTED_SKIP=''
@@ -380,8 +385,10 @@ lint_file_length_rule() {
       f=$(_lint_names 'file-length-limit' .golangci.yaml .golangci.yml .golangci.toml .golangci.json) \
         && printf 'revive file-length-limit in %s' "$f" ;;
     typescript|javascript)
+      # eslint.config.ldd.mjs is the plugin's recommended fragment: a repository
+      # that adopts it keeps it beside eslint.config.js and imports it.
       local configs=(eslint.config.js eslint.config.mjs eslint.config.cjs eslint.config.ts eslint.config.mts eslint.config.cts
-                     .eslintrc .eslintrc.js .eslintrc.cjs .eslintrc.json .eslintrc.yml .eslintrc.yaml)
+                     eslint.config.ldd.mjs .eslintrc .eslintrc.js .eslintrc.cjs .eslintrc.json .eslintrc.yml .eslintrc.yaml)
       if f=$(_lint_names 'sonarjs/max-lines([^-a-zA-Z]|$)' "${configs[@]}"); then
         printf 'sonarjs/max-lines in %s' "$f"
       elif f=$(_lint_names '(^|[^-/a-zA-Z])max-lines([^-a-zA-Z]|$)' "${configs[@]}"); then
@@ -542,6 +549,16 @@ else
   finish
 fi
 
+begin "the recommended fragment, kept as its own file and imported, hands file length to the linter"
+if [[ -z "$FX_ADOPTED_CONFIG" ]]; then skip "this language's setup is copied into the linter's own config"; finish
+else
+  cp "$(dirname "$LINT")/../setup/$FX_ADOPTED_CONFIG" "$REPO/$FX_ADOPTED_CONFIG"
+  write_src "src/over$FX_EXT" $((MAX_LINES + 50))
+  run_lint file-length
+  expect_exit 0 && expect_has "held by " && expect_has "in $FX_ADOPTED_CONFIG" && expect_no_finding && ok
+  finish
+fi
+
 begin ".ldd-lint.yaml sets the limit when the linter holds none"
 printf 'file_max_lines: 100  # this repository\n' > "$REPO/.ldd-lint.yaml"
 write_src "src/a$FX_EXT" 101
diff --git a/linter-driven-development/scripts/ldd-scope_test.sh b/linter-driven-development/scripts/ldd-scope_test.sh
index 07a9edd..9ef9d3b 100755
--- a/linter-driven-development/scripts/ldd-scope_test.sh
+++ b/linter-driven-development/scripts/ldd-scope_test.sh
@@ -123,6 +123,9 @@ mk_repo() { fx_write_marker "$REPO" fixture; fx_write_code; mk_docs; }
 #                      shape of the language's rule ids in that table, and
 #                      FX_ROUTED_SKIP the ids the config leaves out on purpose;
 #                      all "" when the plugin's table names no linter rule
+#   FX_ADOPTED_CONFIG  the name under which a repository keeps the plugin's
+#                      recommended config as its own file and imports it; ""
+#                      when the setup is copied into the linter's own config
 #   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
 #                      the file-length limit, and FX_LENGTH_RULE its rule; both
 #                      "" when the language's linter has no file-length rule
@@ -144,6 +147,7 @@ use_row() {
     go)
       FX_LINTER_CONFIG='.golangci.yml'
       FX_SETUP_FILE='golangci.yaml'
+      FX_ADOPTED_CONFIG=''
       FX_ROUTED_FILE=''
       FX_RULE_ID_RE=''
       FX_ROUTED_SKIP=''
@@ -161,6 +165,7 @@ use_row() {
     python)
       FX_LINTER_CONFIG='.pylintrc'
       FX_SETUP_FILE=''
+      FX_ADOPTED_CONFIG=''
       FX_ROUTED_FILE=''
       FX_RULE_ID_RE=''
       FX_ROUTED_SKIP=''
diff --git a/linter-driven-development/setup/eslint.config.ldd.mjs b/linter-driven-development/setup/eslint.config.ldd.mjs
index 4ccd360..85da438 100644
--- a/linter-driven-development/setup/eslint.config.ldd.mjs
+++ b/linter-driven-development/setup/eslint.config.ldd.mjs
@@ -48,8 +48,9 @@ export default [
       'sonarjs/cognitive-complexity': ['error', 15],
       'sonarjs/cyclomatic-complexity': ['error', { threshold: 10 }],
       'sonarjs/expression-complexity': ['error', { max: 5 }],
-      'sonarjs/max-lines-per-function': ['error', { maximum: 200 }],
-      'sonarjs/nested-control-flow': ['error', { maximumNestingLevel: 4 }],
+      // R3's limits: more than 50 lines or more than 2 nesting levels
+      'sonarjs/max-lines-per-function': ['error', { maximum: 50 }],
+      'sonarjs/nested-control-flow': ['error', { maximumNestingLevel: 2 }],
       'sonarjs/no-nested-conditional': 'error',
       'sonarjs/no-nested-functions': 'error',
       'sonarjs/elseif-without-else': 'error',
diff --git a/linter-driven-development/setup/ruff.toml b/linter-driven-development/setup/ruff.toml
index 1f91e7f..03571ca 100644
--- a/linter-driven-development/setup/ruff.toml
+++ b/linter-driven-development/setup/ruff.toml
@@ -16,7 +16,10 @@
 # Adopt it on an existing codebase one change at a time: run ruff on the files
 # changed since the merge base with main, so old code is not a wall of
 # findings on day one:
-#   git diff --name-only --diff-filter=d "$(git merge-base HEAD main)" -- '*.py' | xargs ruff check
+#   git diff -z --name-only --diff-filter=d "$(git merge-base HEAD main)" -- '*.py' \
+#     | xargs -0 sh -c '[ "$#" -eq 0 ] || ruff check "$@"' sh
+# The sh guard keeps an empty change list from checking the whole repository,
+# and -z with -0 keeps a path with spaces whole.
 
 [lint]
 # PLR1702 (nested blocks) is a preview rule. Preview mode also turns on preview
@@ -47,7 +50,7 @@ max-args = 4          # self and cls are not counted
 max-branches = 12
 max-returns = 6
 max-statements = 50
-max-nested-blocks = 5
+max-nested-blocks = 2  # R3: more than 2 nesting levels
 
 [lint.per-file-ignores]
 # Tests repeat literals and take many fixtures by design.
diff --git a/python-linter-driven-development/scripts/ldd-detect_test.sh b/python-linter-driven-development/scripts/ldd-detect_test.sh
index 33300cb..739b371 100644
--- a/python-linter-driven-development/scripts/ldd-detect_test.sh
+++ b/python-linter-driven-development/scripts/ldd-detect_test.sh
@@ -147,6 +147,9 @@ questions_in_rules() {
 #                      shape of the language's rule ids in that table, and
 #                      FX_ROUTED_SKIP the ids the config leaves out on purpose;
 #                      all "" when the plugin's table names no linter rule
+#   FX_ADOPTED_CONFIG  the name under which a repository keeps the plugin's
+#                      recommended config as its own file and imports it; ""
+#                      when the setup is copied into the linter's own config
 #   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
 #                      the file-length limit, and FX_LENGTH_RULE its rule; both
 #                      "" when the language's linter has no file-length rule
@@ -166,6 +169,7 @@ FX_NATIVE="python"
 use_row() {
   FX_LINTER_CONFIG='pyproject.toml'
   FX_SETUP_FILE=''
+  FX_ADOPTED_CONFIG=''
   FX_ROUTED_FILE='ruff.toml'
   FX_RULE_ID_RE='^[A-Z]+[0-9]+$'
   FX_ROUTED_SKIP=''
diff --git a/python-linter-driven-development/scripts/ldd-lint.sh b/python-linter-driven-development/scripts/ldd-lint.sh
index 4ca2b89..bed3e0d 100755
--- a/python-linter-driven-development/scripts/ldd-lint.sh
+++ b/python-linter-driven-development/scripts/ldd-lint.sh
@@ -322,8 +322,10 @@ lint_file_length_rule() {
       f=$(_lint_names 'file-length-limit' .golangci.yaml .golangci.yml .golangci.toml .golangci.json) \
         && printf 'revive file-length-limit in %s' "$f" ;;
     typescript|javascript)
+      # eslint.config.ldd.mjs is the plugin's recommended fragment: a repository
+      # that adopts it keeps it beside eslint.config.js and imports it.
       local configs=(eslint.config.js eslint.config.mjs eslint.config.cjs eslint.config.ts eslint.config.mts eslint.config.cts
-                     .eslintrc .eslintrc.js .eslintrc.cjs .eslintrc.json .eslintrc.yml .eslintrc.yaml)
+                     eslint.config.ldd.mjs .eslintrc .eslintrc.js .eslintrc.cjs .eslintrc.json .eslintrc.yml .eslintrc.yaml)
       if f=$(_lint_names 'sonarjs/max-lines([^-a-zA-Z]|$)' "${configs[@]}"); then
         printf 'sonarjs/max-lines in %s' "$f"
       elif f=$(_lint_names '(^|[^-/a-zA-Z])max-lines([^-a-zA-Z]|$)' "${configs[@]}"); then
diff --git a/python-linter-driven-development/scripts/ldd-lint_test.sh b/python-linter-driven-development/scripts/ldd-lint_test.sh
index 1beed4a..3e55303 100644
--- a/python-linter-driven-development/scripts/ldd-lint_test.sh
+++ b/python-linter-driven-development/scripts/ldd-lint_test.sh
@@ -111,6 +111,9 @@ fill_dir() {
 #                      shape of the language's rule ids in that table, and
 #                      FX_ROUTED_SKIP the ids the config leaves out on purpose;
 #                      all "" when the plugin's table names no linter rule
+#   FX_ADOPTED_CONFIG  the name under which a repository keeps the plugin's
+#                      recommended config as its own file and imports it; ""
+#                      when the setup is copied into the linter's own config
 #   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
 #                      the file-length limit, and FX_LENGTH_RULE its rule; both
 #                      "" when the language's linter has no file-length rule
@@ -130,6 +133,7 @@ FX_NATIVE="python"
 use_row() {
   FX_LINTER_CONFIG='pyproject.toml'
   FX_SETUP_FILE=''
+  FX_ADOPTED_CONFIG=''
   FX_ROUTED_FILE='ruff.toml'
   FX_RULE_ID_RE='^[A-Z]+[0-9]+$'
   FX_ROUTED_SKIP=''
@@ -308,8 +312,10 @@ lint_file_length_rule() {
       f=$(_lint_names 'file-length-limit' .golangci.yaml .golangci.yml .golangci.toml .golangci.json) \
         && printf 'revive file-length-limit in %s' "$f" ;;
     typescript|javascript)
+      # eslint.config.ldd.mjs is the plugin's recommended fragment: a repository
+      # that adopts it keeps it beside eslint.config.js and imports it.
       local configs=(eslint.config.js eslint.config.mjs eslint.config.cjs eslint.config.ts eslint.config.mts eslint.config.cts
-                     .eslintrc .eslintrc.js .eslintrc.cjs .eslintrc.json .eslintrc.yml .eslintrc.yaml)
+                     eslint.config.ldd.mjs .eslintrc .eslintrc.js .eslintrc.cjs .eslintrc.json .eslintrc.yml .eslintrc.yaml)
       if f=$(_lint_names 'sonarjs/max-lines([^-a-zA-Z]|$)' "${configs[@]}"); then
         printf 'sonarjs/max-lines in %s' "$f"
       elif f=$(_lint_names '(^|[^-/a-zA-Z])max-lines([^-a-zA-Z]|$)' "${configs[@]}"); then
@@ -470,6 +476,16 @@ else
   finish
 fi
 
+begin "the recommended fragment, kept as its own file and imported, hands file length to the linter"
+if [[ -z "$FX_ADOPTED_CONFIG" ]]; then skip "this language's setup is copied into the linter's own config"; finish
+else
+  cp "$(dirname "$LINT")/../setup/$FX_ADOPTED_CONFIG" "$REPO/$FX_ADOPTED_CONFIG"
+  write_src "src/over$FX_EXT" $((MAX_LINES + 50))
+  run_lint file-length
+  expect_exit 0 && expect_has "held by " && expect_has "in $FX_ADOPTED_CONFIG" && expect_no_finding && ok
+  finish
+fi
+
 begin ".ldd-lint.yaml sets the limit when the linter holds none"
 printf 'file_max_lines: 100  # this repository\n' > "$REPO/.ldd-lint.yaml"
 write_src "src/a$FX_EXT" 101
diff --git a/python-linter-driven-development/scripts/ldd-scope_test.sh b/python-linter-driven-development/scripts/ldd-scope_test.sh
index 11ca084..fbd7a47 100755
--- a/python-linter-driven-development/scripts/ldd-scope_test.sh
+++ b/python-linter-driven-development/scripts/ldd-scope_test.sh
@@ -123,6 +123,9 @@ mk_repo() { fx_write_marker "$REPO" fixture; fx_write_code; mk_docs; }
 #                      shape of the language's rule ids in that table, and
 #                      FX_ROUTED_SKIP the ids the config leaves out on purpose;
 #                      all "" when the plugin's table names no linter rule
+#   FX_ADOPTED_CONFIG  the name under which a repository keeps the plugin's
+#                      recommended config as its own file and imports it; ""
+#                      when the setup is copied into the linter's own config
 #   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
 #                      the file-length limit, and FX_LENGTH_RULE its rule; both
 #                      "" when the language's linter has no file-length rule
@@ -142,6 +145,7 @@ FX_NATIVE="python"
 use_row() {
   FX_LINTER_CONFIG='pyproject.toml'
   FX_SETUP_FILE=''
+  FX_ADOPTED_CONFIG=''
   FX_ROUTED_FILE='ruff.toml'
   FX_RULE_ID_RE='^[A-Z]+[0-9]+$'
   FX_ROUTED_SKIP=''
diff --git a/python-linter-driven-development/setup/eslint.config.ldd.mjs b/python-linter-driven-development/setup/eslint.config.ldd.mjs
index 4ccd360..85da438 100644
--- a/python-linter-driven-development/setup/eslint.config.ldd.mjs
+++ b/python-linter-driven-development/setup/eslint.config.ldd.mjs
@@ -48,8 +48,9 @@ export default [
       'sonarjs/cognitive-complexity': ['error', 15],
       'sonarjs/cyclomatic-complexity': ['error', { threshold: 10 }],
       'sonarjs/expression-complexity': ['error', { max: 5 }],
-      'sonarjs/max-lines-per-function': ['error', { maximum: 200 }],
-      'sonarjs/nested-control-flow': ['error', { maximumNestingLevel: 4 }],
+      // R3's limits: more than 50 lines or more than 2 nesting levels
+      'sonarjs/max-lines-per-function': ['error', { maximum: 50 }],
+      'sonarjs/nested-control-flow': ['error', { maximumNestingLevel: 2 }],
       'sonarjs/no-nested-conditional': 'error',
       'sonarjs/no-nested-functions': 'error',
       'sonarjs/elseif-without-else': 'error',
diff --git a/python-linter-driven-development/setup/ruff.toml b/python-linter-driven-development/setup/ruff.toml
index 1f91e7f..03571ca 100644
--- a/python-linter-driven-development/setup/ruff.toml
+++ b/python-linter-driven-development/setup/ruff.toml
@@ -16,7 +16,10 @@
 # Adopt it on an existing codebase one change at a time: run ruff on the files
 # changed since the merge base with main, so old code is not a wall of
 # findings on day one:
-#   git diff --name-only --diff-filter=d "$(git merge-base HEAD main)" -- '*.py' | xargs ruff check
+#   git diff -z --name-only --diff-filter=d "$(git merge-base HEAD main)" -- '*.py' \
+#     | xargs -0 sh -c '[ "$#" -eq 0 ] || ruff check "$@"' sh
+# The sh guard keeps an empty change list from checking the whole repository,
+# and -z with -0 keeps a path with spaces whole.
 
 [lint]
 # PLR1702 (nested blocks) is a preview rule. Preview mode also turns on preview
@@ -47,7 +50,7 @@ max-args = 4          # self and cls are not counted
 max-branches = 12
 max-returns = 6
 max-statements = 50
-max-nested-blocks = 5
+max-nested-blocks = 2  # R3: more than 2 nesting levels
 
 [lint.per-file-ignores]
 # Tests repeat literals and take many fixtures by design.
diff --git a/ts-react-linter-driven-development/scripts/ldd-detect_test.sh b/ts-react-linter-driven-development/scripts/ldd-detect_test.sh
index 501eb6d..10b19c4 100644
--- a/ts-react-linter-driven-development/scripts/ldd-detect_test.sh
+++ b/ts-react-linter-driven-development/scripts/ldd-detect_test.sh
@@ -147,6 +147,9 @@ questions_in_rules() {
 #                      shape of the language's rule ids in that table, and
 #                      FX_ROUTED_SKIP the ids the config leaves out on purpose;
 #                      all "" when the plugin's table names no linter rule
+#   FX_ADOPTED_CONFIG  the name under which a repository keeps the plugin's
+#                      recommended config as its own file and imports it; ""
+#                      when the setup is copied into the linter's own config
 #   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
 #                      the file-length limit, and FX_LENGTH_RULE its rule; both
 #                      "" when the language's linter has no file-length rule
@@ -169,6 +172,7 @@ FX_NATIVE="typescript"
 use_row() {
   FX_LINTER_CONFIG='eslint.config.mjs'
   FX_SETUP_FILE='eslint.config.ldd.mjs'
+  FX_ADOPTED_CONFIG='eslint.config.ldd.mjs'
   FX_ROUTED_FILE='eslint.config.ldd.mjs'
   FX_RULE_ID_RE='^(@[a-z-]+/)?[a-z-]+(/[a-z*-]+)?$'
   # no-restricted-syntax needs the repository's config module path;
diff --git a/ts-react-linter-driven-development/scripts/ldd-lint.sh b/ts-react-linter-driven-development/scripts/ldd-lint.sh
index ee0318b..54c6952 100755
--- a/ts-react-linter-driven-development/scripts/ldd-lint.sh
+++ b/ts-react-linter-driven-development/scripts/ldd-lint.sh
@@ -332,8 +332,10 @@ lint_file_length_rule() {
       f=$(_lint_names 'file-length-limit' .golangci.yaml .golangci.yml .golangci.toml .golangci.json) \
         && printf 'revive file-length-limit in %s' "$f" ;;
     typescript|javascript)
+      # eslint.config.ldd.mjs is the plugin's recommended fragment: a repository
+      # that adopts it keeps it beside eslint.config.js and imports it.
       local configs=(eslint.config.js eslint.config.mjs eslint.config.cjs eslint.config.ts eslint.config.mts eslint.config.cts
-                     .eslintrc .eslintrc.js .eslintrc.cjs .eslintrc.json .eslintrc.yml .eslintrc.yaml)
+                     eslint.config.ldd.mjs .eslintrc .eslintrc.js .eslintrc.cjs .eslintrc.json .eslintrc.yml .eslintrc.yaml)
       if f=$(_lint_names 'sonarjs/max-lines([^-a-zA-Z]|$)' "${configs[@]}"); then
         printf 'sonarjs/max-lines in %s' "$f"
       elif f=$(_lint_names '(^|[^-/a-zA-Z])max-lines([^-a-zA-Z]|$)' "${configs[@]}"); then
diff --git a/ts-react-linter-driven-development/scripts/ldd-lint_test.sh b/ts-react-linter-driven-development/scripts/ldd-lint_test.sh
index 75c3cff..cfec7bf 100644
--- a/ts-react-linter-driven-development/scripts/ldd-lint_test.sh
+++ b/ts-react-linter-driven-development/scripts/ldd-lint_test.sh
@@ -111,6 +111,9 @@ fill_dir() {
 #                      shape of the language's rule ids in that table, and
 #                      FX_ROUTED_SKIP the ids the config leaves out on purpose;
 #                      all "" when the plugin's table names no linter rule
+#   FX_ADOPTED_CONFIG  the name under which a repository keeps the plugin's
+#                      recommended config as its own file and imports it; ""
+#                      when the setup is copied into the linter's own config
 #   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
 #                      the file-length limit, and FX_LENGTH_RULE its rule; both
 #                      "" when the language's linter has no file-length rule
@@ -133,6 +136,7 @@ FX_NATIVE="typescript"
 use_row() {
   FX_LINTER_CONFIG='eslint.config.mjs'
   FX_SETUP_FILE='eslint.config.ldd.mjs'
+  FX_ADOPTED_CONFIG='eslint.config.ldd.mjs'
   FX_ROUTED_FILE='eslint.config.ldd.mjs'
   FX_RULE_ID_RE='^(@[a-z-]+/)?[a-z-]+(/[a-z*-]+)?$'
   # no-restricted-syntax needs the repository's config module path;
@@ -314,8 +318,10 @@ lint_file_length_rule() {
       f=$(_lint_names 'file-length-limit' .golangci.yaml .golangci.yml .golangci.toml .golangci.json) \
         && printf 'revive file-length-limit in %s' "$f" ;;
     typescript|javascript)
+      # eslint.config.ldd.mjs is the plugin's recommended fragment: a repository
+      # that adopts it keeps it beside eslint.config.js and imports it.
       local configs=(eslint.config.js eslint.config.mjs eslint.config.cjs eslint.config.ts eslint.config.mts eslint.config.cts
-                     .eslintrc .eslintrc.js .eslintrc.cjs .eslintrc.json .eslintrc.yml .eslintrc.yaml)
+                     eslint.config.ldd.mjs .eslintrc .eslintrc.js .eslintrc.cjs .eslintrc.json .eslintrc.yml .eslintrc.yaml)
       if f=$(_lint_names 'sonarjs/max-lines([^-a-zA-Z]|$)' "${configs[@]}"); then
         printf 'sonarjs/max-lines in %s' "$f"
       elif f=$(_lint_names '(^|[^-/a-zA-Z])max-lines([^-a-zA-Z]|$)' "${configs[@]}"); then
@@ -476,6 +482,16 @@ else
   finish
 fi
 
+begin "the recommended fragment, kept as its own file and imported, hands file length to the linter"
+if [[ -z "$FX_ADOPTED_CONFIG" ]]; then skip "this language's setup is copied into the linter's own config"; finish
+else
+  cp "$(dirname "$LINT")/../setup/$FX_ADOPTED_CONFIG" "$REPO/$FX_ADOPTED_CONFIG"
+  write_src "src/over$FX_EXT" $((MAX_LINES + 50))
+  run_lint file-length
+  expect_exit 0 && expect_has "held by " && expect_has "in $FX_ADOPTED_CONFIG" && expect_no_finding && ok
+  finish
+fi
+
 begin ".ldd-lint.yaml sets the limit when the linter holds none"
 printf 'file_max_lines: 100  # this repository\n' > "$REPO/.ldd-lint.yaml"
 write_src "src/a$FX_EXT" 101
diff --git a/ts-react-linter-driven-development/scripts/ldd-scope_test.sh b/ts-react-linter-driven-development/scripts/ldd-scope_test.sh
index b9ad613..76464f4 100755
--- a/ts-react-linter-driven-development/scripts/ldd-scope_test.sh
+++ b/ts-react-linter-driven-development/scripts/ldd-scope_test.sh
@@ -123,6 +123,9 @@ mk_repo() { fx_write_marker "$REPO" fixture; fx_write_code; mk_docs; }
 #                      shape of the language's rule ids in that table, and
 #                      FX_ROUTED_SKIP the ids the config leaves out on purpose;
 #                      all "" when the plugin's table names no linter rule
+#   FX_ADOPTED_CONFIG  the name under which a repository keeps the plugin's
+#                      recommended config as its own file and imports it; ""
+#                      when the setup is copied into the linter's own config
 #   FX_SETUP_FILE      the plugin's recommended config under setup/ that holds
 #                      the file-length limit, and FX_LENGTH_RULE its rule; both
 #                      "" when the language's linter has no file-length rule
@@ -145,6 +148,7 @@ FX_NATIVE="typescript"
 use_row() {
   FX_LINTER_CONFIG='eslint.config.mjs'
   FX_SETUP_FILE='eslint.config.ldd.mjs'
+  FX_ADOPTED_CONFIG='eslint.config.ldd.mjs'
   FX_ROUTED_FILE='eslint.config.ldd.mjs'
   FX_RULE_ID_RE='^(@[a-z-]+/)?[a-z-]+(/[a-z*-]+)?$'
   # no-restricted-syntax needs the repository's config module path;
diff --git a/ts-react-linter-driven-development/setup/eslint.config.ldd.mjs b/ts-react-linter-driven-development/setup/eslint.config.ldd.mjs
index 4ccd360..85da438 100644
--- a/ts-react-linter-driven-development/setup/eslint.config.ldd.mjs
+++ b/ts-react-linter-driven-development/setup/eslint.config.ldd.mjs
@@ -48,8 +48,9 @@ export default [
       'sonarjs/cognitive-complexity': ['error', 15],
       'sonarjs/cyclomatic-complexity': ['error', { threshold: 10 }],
       'sonarjs/expression-complexity': ['error', { max: 5 }],
-      'sonarjs/max-lines-per-function': ['error', { maximum: 200 }],
-      'sonarjs/nested-control-flow': ['error', { maximumNestingLevel: 4 }],
+      // R3's limits: more than 50 lines or more than 2 nesting levels
+      'sonarjs/max-lines-per-function': ['error', { maximum: 50 }],
+      'sonarjs/nested-control-flow': ['error', { maximumNestingLevel: 2 }],
       'sonarjs/no-nested-conditional': 'error',
       'sonarjs/no-nested-functions': 'error',
       'sonarjs/elseif-without-else': 'error',
diff --git a/ts-react-linter-driven-development/setup/ruff.toml b/ts-react-linter-driven-development/setup/ruff.toml
index 1f91e7f..03571ca 100644
--- a/ts-react-linter-driven-development/setup/ruff.toml
+++ b/ts-react-linter-driven-development/setup/ruff.toml
@@ -16,7 +16,10 @@
 # Adopt it on an existing codebase one change at a time: run ruff on the files
 # changed since the merge base with main, so old code is not a wall of
 # findings on day one:
-#   git diff --name-only --diff-filter=d "$(git merge-base HEAD main)" -- '*.py' | xargs ruff check
+#   git diff -z --name-only --diff-filter=d "$(git merge-base HEAD main)" -- '*.py' \
+#     | xargs -0 sh -c '[ "$#" -eq 0 ] || ruff check "$@"' sh
+# The sh guard keeps an empty change list from checking the whole repository,
+# and -z with -0 keeps a path with spaces whole.
 
 [lint]
 # PLR1702 (nested blocks) is a preview rule. Preview mode also turns on preview
@@ -47,7 +50,7 @@ max-args = 4          # self and cls are not counted
 max-branches = 12
 max-returns = 6
 max-statements = 50
-max-nested-blocks = 5
+max-nested-blocks = 2  # R3: more than 2 nesting levels
 
 [lint.per-file-ignores]
 # Tests repeat literals and take many fixtures by design.