diff --git a/PLAN.md b/PLAN.md
new file mode 100644
index 0000000..24af5e1
--- /dev/null
+++ b/PLAN.md
@@ -0,0 +1,42 @@
+# PLAN — Issue #127 slice: `src/engine/loop.ts` slim-down (tests-first)
+
+## Goal
+Reduce `src/engine/loop.ts:1-6567` (6567 lines, single `HeadlessSession` class at `src/engine/loop.ts:1363`) toward [`docs/typescript-standards.md`](docs/typescript-standards.md:17-24) (250 file / 200 class / 20 function lines) with **no behavior change**. Land a coherent partial split with tests + green gates if the full split does not fit; do not leave a sprawling WIP.
+
+## Scope boundaries (hard)
+- Owns ONLY `src/engine/loop.ts`. Do NOT touch `src/orchestrator/cli.ts`, `resume.ts`, or anything a sibling worker owns per the issue brief.
+- No behavior change: pure moves + thin delegation. Keep all 27 existing importers compiling (importers include [`src/cli.ts`](src/cli.ts:1), [`src/index.ts`](src/index.ts:1), [`src/orchestrator/pipeline.ts`](src/orchestrator/pipeline.ts:1)); keep `src/engine/loop.ts` as a re-export facade during the split.
+- Tests-first is mandatory: test must exist and pass BEFORE the unit it covers is reshaped.
+
+## Starting state (verified)
+- Monolith: `src/engine/loop.ts:1363` `HeadlessSession` + config interfaces `src/engine/loop.ts:744` (`HeadlessSessionConfig`), `src/engine/loop.ts:1218` (`ResolvedSessionConfig`), `src/engine/loop.ts:1208` (`SessionRunState`).
+- Largest method: [`runIterations()`](src/engine/loop.ts:3416) spans ~3416–5487 (~2000 lines) — the endgame; do it last, and accept a partial win.
+- Condensation cluster (extract as a group): [`maybeCondenseHistory()`](src/engine/loop.ts:2584), [`fireBackgroundCondense()`](src/engine/loop.ts:2862), [`applyBackgroundCondense()`](src/engine/loop.ts:2985), [`recordCondensationUsage()`](src/engine/loop.ts:3103), [`recordHandoffCondensationUsage()`](src/engine/loop.ts:3135), [`writeIterationCapHandoff()`](src/engine/loop.ts:3162), [`recordAuxLlmUsage()`](src/engine/loop.ts:3241), [`condensationClient()`](src/engine/loop.ts:3378). Prior art already extracted: [`src/engine/condense.ts:1-60`](src/engine/condense.ts:1), [`src/engine/handoff.ts:42-52`](src/engine/handoff.ts:42).
+- Handler cluster: [`handleNewTask()`](src/engine/loop.ts:5662), [`handleSwitchMode()`](src/engine/loop.ts:5842), [`handleExtensionManage()`](src/engine/loop.ts:5595), [`handleExtensionCall()`](src/engine/loop.ts:5641), [`handleActivateSkill()`](src/engine/loop.ts:6060), [`handleReadSkillReference()`](src/engine/loop.ts:6083), [`handleRequestTool()`](src/engine/loop.ts:6105), [`handleListTools()`](src/engine/loop.ts:6056).
+- Pure free functions (lowest-risk first extraction): [`combineAbortSignals()`](src/engine/loop.ts:173), [`isReadOnlyDirectCall()`](src/engine/loop.ts:361), [`isReadOnlyTurnCall()`](src/engine/loop.ts:379), [`artifactRejectionNudgeMessage()`](src/engine/loop.ts:524), [`stripSupersededReasoning()`](src/engine/loop.ts:572), [`countVerifiedCitations()`](src/engine/loop.ts:613), [`matchingArtifactFileStatus()`](src/engine/loop.ts:649), [`hasUncommittedTrackedChanges()`](src/engine/loop.ts:709), [`estimateTokenSize()`](src/engine/loop.ts:6283), [`summarizeToolArg()`](src/engine/loop.ts:6300), [`truncateHistory()`](src/engine/loop.ts:6474), [`sameToolNames()`](src/engine/loop.ts:6387), [`messagesPrefixEquals()`](src/engine/loop.ts:6415), `env*` helpers [`src/engine/loop.ts:6493-6560`](src/engine/loop.ts:6493).
+- Existing test style: plain `node:assert/strict` scripts via `tsx`, auto-discovered (`scripts/run-tests.mjs:41-55`). Main suite [`src/engine/__tests__/loop.test.ts:1-80`](src/engine/__tests__/loop.test.ts:1) (4402 lines, FakeLlmClient DI pattern at `src/engine/__tests__/loop.test.ts:44-65`). Focused suites exist for condense/pause/inject/switch-mode — mirror them.
+- Check tooling: [`scripts/check-code-standards.mjs:18`](scripts/check-code-standards.mjs:18) limits, [`scripts/check-architecture.mjs:19`](scripts/check-architecture.mjs:19) limits; baselines `scripts/code-standards-baseline.json`, `scripts/architecture-baseline.json` (content-anchored; regenerate with `--write-baseline` in the SAME change, never by hand).
+
+## Steps
+1. **Measure (record numbers for the closing report).** Run: `npm run check-standards -- src/engine/loop.ts`, `npm run check-architecture -- src/engine/loop.ts` (or full runs), `npm run coverage -- --filter engine`. Save outputs; also `wc -l src/engine/loop.ts`.
+2. **Tests FIRST — pure helpers.** Add `src/engine/__tests__/loop-helpers.test.ts` covering every pure function to be moved first (`combineAbortSignals`, `isReadOnlyDirectCall/TurnCall`, `artifactRejectionNudgeMessage`, `stripSupersededReasoning`, `countVerifiedCitations` + `matchingArtifactFileStatus` with temp dirs, `estimateTokenSize`, `summarizeToolArg`, `truncateHistory`, `sameToolNames`, `messagesPrefixEquals`, env helpers). Keep each test file <250 lines — split into `loop-helpers-*.test.ts` if needed. Run `npx tsx <file>` then `npm test -- loop-helpers` until green. Do not move code until these pass.
+3. **Extract pure helpers.** Create `src/engine/loop-helpers.ts` (or two files if >250 lines: `loop-pure.ts` + `loop-history.ts` for truncate/messages fns). Move the step-2 functions verbatim, fix imports, re-export from `loop.ts` so existing `import { … } from "../loop.js"` in tests (`src/engine/__tests__/loop.test.ts:17-30`) keeps working. Verify `npx tsc --noEmit`.
+4. **Tests FIRST — condensation.** Add `src/engine/__tests__/loop-condense.test.ts` using the FakeLlmClient pattern for `maybeCondenseHistory` / `fireBackgroundCondense` / `applyBackgroundCondense` / usage recorders. Reuse fixtures from `src/engine/__tests__/condense.test.ts`, not new harness machinery.
+5. **Extract condensation.** Create `src/engine/loop-condense.ts` taking explicit params (messages, budgetTracker, contextWindowTokens) rather than reaching into private session fields; `HeadlessSession` methods at `src/engine/loop.ts:2584-3415` become thin delegates. Follow the `src/engine/condense.ts` / `src/engine/handoff.ts` module idiom (one layout/concern per file). Verify typecheck.
+6. **Tests FIRST + extract handlers.** Add `src/engine/__tests__/loop-handlers.test.ts` for `handleSwitchMode` / `handleNewTask` / extension + skill handlers with fake executor/registry (see existing `switch-mode.test.ts`, `new-task.test.ts`). Then create `src/engine/loop-handlers.ts`; pass a minimal session-context interface (not the whole `HeadlessSession`) to avoid an import cycle (`cycle` rule allows zero cycles).
+7. **runIterations — partial, coherent only.** Do NOT attempt to split the whole `src/engine/loop.ts:3416-5487` in one go. If time permits, extract ONE seam (e.g. pause/inject polling `src/engine/loop.ts:2439-2583` → `loop-poll.ts`, or checkpoint helpers `src/engine/loop.ts:5488-5575` → `loop-checkpoints.ts`). Prefer landing steps 2–6 green over a half-split runIterations.
+8. **Baselines + gates (all green, same change).** `npx tsc --noEmit`; `npm test` (full); `npm run check-standards`; `npm run check-architecture`; regenerate both baselines in the same commit(s); `npm run coverage -- --min 24` must not regress vs step 1.
+9. **Commit / PR.** One logical commit per extraction (`git add` + `git commit` with `#127` in message). Push branch, open PR (ready, not draft) against `master` linking `#127`. Close with the ORCHESTRATOR_TASK.md template (Files changed / Baseline before+after / Boot check / Residual risk / PR link).
+
+## Verification
+- `npx tsc --noEmit` clean.
+- `npm test` full passes (runner: `scripts/run-tests.mjs:105-177`, fail-fast, sorted).
+- `npm run check-standards` and `npm run check-architecture` pass with regenerated baselines in the same change.
+- `npm run coverage -- --min 24` passes; `npm run coverage -- --filter engine` recorded before/after (must not regress).
+- Boot check: N/A (library refactor, no CLI behavior change) — state that explicitly in the closing report unless a touched path warrants `npx tsx src/cli.ts --help`.
+
+## Risks / notes
+- Content-anchored baselines: editing a flagged line creates a NEW violation key — expect to fix (not baseline) touched lines; keep lines ≤80 chars and functions ≤20 lines in all new files.
+- Cycle risk: new `loop-*.ts` modules must not import `loop.ts` back (zero `cycle` tolerance). Inject a narrow context interface instead.
+- `runIterations` statefulness (locals at `src/engine/loop.ts:3419-3456` like `completionNudged`, `lastExecuteCommandFailed`) makes extraction error-prone — default to leaving it intact and claiming the helpers+condensation+handlers win.
+- Scratch only under `.headlesscode/scratch/`; never `/tmp` (outside-workspace writes fail).
diff --git a/scripts/architecture-baseline.json b/scripts/architecture-baseline.json
index a286f38..c836ce8 100644
--- a/scripts/architecture-baseline.json
+++ b/scripts/architecture-baseline.json
@@ -1,9 +1,9 @@
 {
  "version": 1,
  "violations": [
-  "clone 00803486e758 src/engine/__tests__/parser.test.ts,src/engine/__tests__/summarize-tool-arg.test.ts,src/memory/__tests__/embed.test.ts,src/memory/__tests__/summarizer.test.ts",
+  "clone 00803486e758 src/engine/__tests__/loop-helpers-history.test.ts,src/engine/__tests__/loop-helpers-readonly.test.ts,src/engine/__tests__/parser.test.ts,src/engine/__tests__/summarize-tool-arg.test.ts,src/memory/__tests__/embed.test.ts,src/memory/__tests__/summarizer.test.ts",
   "clone 0081a7d462ab src/orchestrator/__tests__/cost-history-cli.test.ts,src/orchestrator/__tests__/cost-history.test.ts",
-  "clone 0152e2318e4e src/engine/__tests__/new-task.test.ts,src/engine/__tests__/parser.test.ts,src/engine/__tests__/summarize-tool-arg.test.ts,src/engine/__tests__/switch-mode.test.ts",
+  "clone 0152e2318e4e src/engine/__tests__/loop-helpers-history.test.ts,src/engine/__tests__/loop-helpers-readonly.test.ts,src/engine/__tests__/new-task.test.ts,src/engine/__tests__/parser.test.ts,src/engine/__tests__/summarize-tool-arg.test.ts,src/engine/__tests__/switch-mode.test.ts",
   "clone 01a56a433e82 src/orchestrator/task-files.ts",
   "clone 01e5839d0892 src/permissions/commands.ts",
   "clone 0288db0ddefd src/orchestrator/cli.ts",
@@ -18,7 +18,7 @@
   "clone 05d4573a34dd src/codesearch/embedder.ts,src/memory/embed.ts",
   "clone 05f9940a16d5 src/decision-proxy/cli.ts,src/orchestrator/cli.ts,src/orchestrator/resume.ts",
   "clone 0654c838248c src/llm/muse.ts,src/llm/openrouter.ts",
-  "clone 0665ce33abe0 src/engine/__tests__/parser.test.ts,src/engine/__tests__/summarize-tool-arg.test.ts",
+  "clone 0665ce33abe0 src/engine/__tests__/loop-helpers-history.test.ts,src/engine/__tests__/loop-helpers-readonly.test.ts,src/engine/__tests__/parser.test.ts,src/engine/__tests__/summarize-tool-arg.test.ts",
   "clone 06b27f6a49e2 src/orchestrator/__tests__/analyze-cli.test.ts",
   "clone 06c2ac64ec1e src/engine/__tests__/condense.test.ts",
   "clone 070bf0935a24 src/engine/loop.ts",
@@ -76,7 +76,7 @@
   "clone 14ae7a9a5f1d src/codesearch/__tests__/backend-selection.test.ts,src/codesearch/__tests__/index.test.ts,src/codesearch/__tests__/search.test.ts,src/config/__tests__/mode-models.test.ts,src/dashboard/__tests__/file-browser-permissions.test.ts,src/dashboard/__tests__/settings.test.ts,src/orchestrator/__tests__/cli.test.ts,src/orchestrator/__tests__/model-resolution.test.ts,src/orchestrator/__tests__/resume.test.ts,src/orchestrator/__tests__/spawn-model.test.ts,src/orchestrator/__tests__/watch.test.ts,src/permissions/__tests__/protected-files.test.ts,src/tools/__tests__/codebase_search.test.ts",
   "clone 14d7e81b5443 src/checkpoints/__tests__/cli.test.ts,src/codemap/__tests__/cli.test.ts,src/dashboard/__tests__/cli.test.ts",
   "clone 15440c983d57 src/checkpoints/cli.ts,src/decision-proxy/cli.ts",
-  "clone 157b83b06b3d src/engine/__tests__/parser.test.ts,src/engine/__tests__/summarize-tool-arg.test.ts,src/memory/__tests__/embed.test.ts,src/memory/__tests__/summarizer.test.ts",
+  "clone 157b83b06b3d src/engine/__tests__/loop-helpers-history.test.ts,src/engine/__tests__/loop-helpers-readonly.test.ts,src/engine/__tests__/parser.test.ts,src/engine/__tests__/summarize-tool-arg.test.ts,src/memory/__tests__/embed.test.ts,src/memory/__tests__/summarizer.test.ts",
   "clone 15d1e6928f43 src/dashboard/server.ts",
   "clone 16271d25ae1f src/llm/preflight.ts",
   "clone 162af6dd3851 src/decision-proxy/__tests__/proxy.test.ts,src/engine/__tests__/switch-mode.test.ts,src/tools/__tests__/codebase_search.test.ts,src/tools/__tests__/execute_command.test.ts",
@@ -342,9 +342,9 @@
   "clone 60c4fdaf31bd src/codesearch/airunner-embedder.ts,src/codesearch/ollama-embedder.ts",
   "clone 61046dbb6410 src/budget/__tests__/budget.test.ts,src/budget/__tests__/concurrency.test.ts,src/budget/__tests__/cost.test.ts,src/checkpoints/__tests__/service.test.ts,src/cloud/__tests__/provider.test.ts,src/codeintel/__tests__/call-graph.test.ts,src/codeintel/__tests__/call-hierarchy.test.ts,src/codeintel/__tests__/find-references.test.ts,src/codeintel/__tests__/go-to-definition.test.ts,src/codeintel/__tests__/hover.test.ts,src/codeintel/__tests__/import-graph.test.ts,src/codeintel/__tests__/outline.test.ts,src/codeintel/__tests__/rename-symbol.test.ts,src/codemap/__tests__/build.test.ts,src/codesearch/__tests__/airunner-embedder.test.ts,src/codesearch/__tests__/chunk.test.ts,src/codesearch/__tests__/files.test.ts,src/codesearch/__tests__/ollama-embedder.test.ts,src/dashboard/__tests__/aggregate.test.ts,src/dashboard/__tests__/chat-thread.test.ts,src/dashboard/__tests__/checkpoints-routes.test.ts,src/dashboard/__tests__/codemap-routes.test.ts,src/dashboard/__tests__/cost-history-routes.test.ts,src/dashboard/__tests__/events.test.ts,src/dashboard/__tests__/projects-routes.test.ts,src/dashboard/__tests__/server.test.ts,src/dashboard/__tests__/session-launch.test.ts,src/dashboard/__tests__/timeline.test.ts,src/deploy/__tests__/gate.test.ts,src/engine/__tests__/condense-async.test.ts,src/engine/__tests__/condense.test.ts,src/engine/__tests__/events.test.ts,src/engine/__tests__/inject-message.test.ts,src/engine/__tests__/local-explore.test.ts,src/engine/__tests__/loop.test.ts,src/engine/__tests__/new-task.test.ts,src/engine/__tests__/pause.test.ts,src/engine/__tests__/switch-mode.test.ts,src/github/__tests__/app-auth.test.ts,src/github/__tests__/cli.test.ts,src/github/__tests__/pr.test.ts,src/github/__tests__/provision.test.ts,src/github/__tests__/push.test.ts,src/index-util.test.ts,src/init/__tests__/cli.test.ts,src/init/__tests__/gitignore.test.ts,src/memory/__tests__/local.test.ts,src/memory/__tests__/memory-wiring.test.ts,src/memory/__tests__/uwuchat.test.ts,src/migrate/cli.test.ts,src/orchestrator/__tests__/arg-cursor.test.ts,src/orchestrator/__tests__/auto-split.test.ts,src/orchestrator/__tests__/cleanup.test.ts,src/orchestrator/__tests__/git-sync.test.ts,src/orchestrator/__tests__/merge-check.test.ts,src/orchestrator/__tests__/pipeline.test.ts,src/orchestrator/__tests__/reviewer.test.ts,src/orchestrator/__tests__/split.test.ts,src/orchestrator/__tests__/state.test.ts,src/orchestrator/__tests__/status-cli.test.ts,src/orchestrator/__tests__/stop-cli.test.ts,src/permissions/__tests__/commands.test.ts,src/permissions/__tests__/store-protection.test.ts,src/project-store.test.ts,src/projects/__tests__/cli.test.ts,src/qa/__tests__/qa.test.ts,src/tools/__tests__/apply_diff.test.ts,src/tools/__tests__/browser-action.test.ts,src/tools/__tests__/decision.test.ts,src/tools/__tests__/describe_image.test.ts,src/tools/__tests__/edit_file.test.ts,src/tools/__tests__/execute_command.test.ts,src/tools/__tests__/language-detect.test.ts,src/tools/__tests__/list-files.test.ts,src/tools/__tests__/local-summarization-gate.test.ts,src/tools/__tests__/output-summarizer.test.ts,src/tools/__tests__/path-safety.test.ts,src/tools/__tests__/read-cache.test.ts,src/tools/__tests__/run-tests.test.ts,src/tools/__tests__/search_replace.test.ts,src/tools/__tests__/update_todo_list.test.ts,src/tools/__tests__/write_to_file.test.ts,src/vision/__tests__/describe.test.ts,src/watcher/__tests__/github.test.ts,src/watcher/__tests__/state.test.ts,src/watcher/__tests__/watch.test.ts",
   "clone 6255fbea917d src/orchestrator/__tests__/cost-history-cli.test.ts,src/orchestrator/__tests__/cost-history.test.ts",
-  "clone 6287c1413aa4 src/budget/__tests__/budget.test.ts,src/budget/__tests__/concurrency.test.ts,src/budget/__tests__/cost.test.ts,src/checkpoints/__tests__/service.test.ts,src/cloud/__tests__/provider.test.ts,src/codeintel/__tests__/call-graph.test.ts,src/codeintel/__tests__/call-hierarchy.test.ts,src/codeintel/__tests__/find-references.test.ts,src/codeintel/__tests__/go-to-definition.test.ts,src/codeintel/__tests__/hover.test.ts,src/codeintel/__tests__/import-graph.test.ts,src/codeintel/__tests__/outline.test.ts,src/codeintel/__tests__/rename-symbol.test.ts,src/codemap/__tests__/build.test.ts,src/codesearch/__tests__/airunner-embedder.test.ts,src/codesearch/__tests__/chunk.test.ts,src/codesearch/__tests__/files.test.ts,src/codesearch/__tests__/ollama-embedder.test.ts,src/dashboard/__tests__/aggregate.test.ts,src/dashboard/__tests__/chat-thread.test.ts,src/dashboard/__tests__/checkpoints-routes.test.ts,src/dashboard/__tests__/codemap-routes.test.ts,src/dashboard/__tests__/cost-history-routes.test.ts,src/dashboard/__tests__/events.test.ts,src/dashboard/__tests__/projects-routes.test.ts,src/dashboard/__tests__/server.test.ts,src/dashboard/__tests__/session-launch.test.ts,src/dashboard/__tests__/timeline.test.ts,src/deploy/__tests__/gate.test.ts,src/engine/__tests__/condense-async.test.ts,src/engine/__tests__/condense.test.ts,src/engine/__tests__/events.test.ts,src/engine/__tests__/inject-message.test.ts,src/engine/__tests__/local-explore.test.ts,src/engine/__tests__/loop.test.ts,src/engine/__tests__/new-task.test.ts,src/engine/__tests__/parser.test.ts,src/engine/__tests__/pause.test.ts,src/engine/__tests__/summarize-tool-arg.test.ts,src/engine/__tests__/switch-mode.test.ts,src/github/__tests__/app-auth.test.ts,src/github/__tests__/cli.test.ts,src/github/__tests__/pr.test.ts,src/github/__tests__/provision.test.ts,src/github/__tests__/push.test.ts,src/index-util.test.ts,src/init/__tests__/cli.test.ts,src/init/__tests__/gitignore.test.ts,src/memory/__tests__/embed.test.ts,src/memory/__tests__/local.test.ts,src/memory/__tests__/memory-wiring.test.ts,src/memory/__tests__/summarizer.test.ts,src/memory/__tests__/uwuchat.test.ts,src/migrate/cli.test.ts,src/orchestrator/__tests__/arg-cursor.test.ts,src/orchestrator/__tests__/auto-split.test.ts,src/orchestrator/__tests__/cleanup.test.ts,src/orchestrator/__tests__/git-sync.test.ts,src/orchestrator/__tests__/merge-check.test.ts,src/orchestrator/__tests__/pipeline.test.ts,src/orchestrator/__tests__/reviewer.test.ts,src/orchestrator/__tests__/split.test.ts,src/orchestrator/__tests__/state.test.ts,src/orchestrator/__tests__/status-cli.test.ts,src/orchestrator/__tests__/stop-cli.test.ts,src/permissions/__tests__/commands.test.ts,src/permissions/__tests__/store-protection.test.ts,src/project-store.test.ts,src/projects/__tests__/cli.test.ts,src/qa/__tests__/qa.test.ts,src/tools/__tests__/apply_diff.test.ts,src/tools/__tests__/browser-action.test.ts,src/tools/__tests__/decision.test.ts,src/tools/__tests__/describe_image.test.ts,src/tools/__tests__/edit_file.test.ts,src/tools/__tests__/execute_command.test.ts,src/tools/__tests__/language-detect.test.ts,src/tools/__tests__/list-files.test.ts,src/tools/__tests__/local-summarization-gate.test.ts,src/tools/__tests__/output-summarizer.test.ts,src/tools/__tests__/read-cache.test.ts,src/tools/__tests__/run-tests.test.ts,src/tools/__tests__/search_replace.test.ts,src/tools/__tests__/update_todo_list.test.ts,src/tools/__tests__/write_to_file.test.ts,src/vision/__tests__/describe.test.ts,src/watcher/__tests__/github.test.ts,src/watcher/__tests__/state.test.ts,src/watcher/__tests__/watch.test.ts",
+  "clone 6287c1413aa4 src/budget/__tests__/budget.test.ts,src/budget/__tests__/concurrency.test.ts,src/budget/__tests__/cost.test.ts,src/checkpoints/__tests__/service.test.ts,src/cloud/__tests__/provider.test.ts,src/codeintel/__tests__/call-graph.test.ts,src/codeintel/__tests__/call-hierarchy.test.ts,src/codeintel/__tests__/find-references.test.ts,src/codeintel/__tests__/go-to-definition.test.ts,src/codeintel/__tests__/hover.test.ts,src/codeintel/__tests__/import-graph.test.ts,src/codeintel/__tests__/outline.test.ts,src/codeintel/__tests__/rename-symbol.test.ts,src/codemap/__tests__/build.test.ts,src/codesearch/__tests__/airunner-embedder.test.ts,src/codesearch/__tests__/chunk.test.ts,src/codesearch/__tests__/files.test.ts,src/codesearch/__tests__/ollama-embedder.test.ts,src/dashboard/__tests__/aggregate.test.ts,src/dashboard/__tests__/chat-thread.test.ts,src/dashboard/__tests__/checkpoints-routes.test.ts,src/dashboard/__tests__/codemap-routes.test.ts,src/dashboard/__tests__/cost-history-routes.test.ts,src/dashboard/__tests__/events.test.ts,src/dashboard/__tests__/projects-routes.test.ts,src/dashboard/__tests__/server.test.ts,src/dashboard/__tests__/session-launch.test.ts,src/dashboard/__tests__/timeline.test.ts,src/deploy/__tests__/gate.test.ts,src/engine/__tests__/condense-async.test.ts,src/engine/__tests__/condense.test.ts,src/engine/__tests__/events.test.ts,src/engine/__tests__/inject-message.test.ts,src/engine/__tests__/local-explore.test.ts,src/engine/__tests__/loop-helpers-history.test.ts,src/engine/__tests__/loop-helpers-readonly.test.ts,src/engine/__tests__/loop.test.ts,src/engine/__tests__/new-task.test.ts,src/engine/__tests__/parser.test.ts,src/engine/__tests__/pause.test.ts,src/engine/__tests__/summarize-tool-arg.test.ts,src/engine/__tests__/switch-mode.test.ts,src/github/__tests__/app-auth.test.ts,src/github/__tests__/cli.test.ts,src/github/__tests__/pr.test.ts,src/github/__tests__/provision.test.ts,src/github/__tests__/push.test.ts,src/index-util.test.ts,src/init/__tests__/cli.test.ts,src/init/__tests__/gitignore.test.ts,src/memory/__tests__/embed.test.ts,src/memory/__tests__/local.test.ts,src/memory/__tests__/memory-wiring.test.ts,src/memory/__tests__/summarizer.test.ts,src/memory/__tests__/uwuchat.test.ts,src/migrate/cli.test.ts,src/orchestrator/__tests__/arg-cursor.test.ts,src/orchestrator/__tests__/auto-split.test.ts,src/orchestrator/__tests__/cleanup.test.ts,src/orchestrator/__tests__/git-sync.test.ts,src/orchestrator/__tests__/merge-check.test.ts,src/orchestrator/__tests__/pipeline.test.ts,src/orchestrator/__tests__/reviewer.test.ts,src/orchestrator/__tests__/split.test.ts,src/orchestrator/__tests__/state.test.ts,src/orchestrator/__tests__/status-cli.test.ts,src/orchestrator/__tests__/stop-cli.test.ts,src/permissions/__tests__/commands.test.ts,src/permissions/__tests__/store-protection.test.ts,src/project-store.test.ts,src/projects/__tests__/cli.test.ts,src/qa/__tests__/qa.test.ts,src/tools/__tests__/apply_diff.test.ts,src/tools/__tests__/browser-action.test.ts,src/tools/__tests__/decision.test.ts,src/tools/__tests__/describe_image.test.ts,src/tools/__tests__/edit_file.test.ts,src/tools/__tests__/execute_command.test.ts,src/tools/__tests__/language-detect.test.ts,src/tools/__tests__/list-files.test.ts,src/tools/__tests__/local-summarization-gate.test.ts,src/tools/__tests__/output-summarizer.test.ts,src/tools/__tests__/read-cache.test.ts,src/tools/__tests__/run-tests.test.ts,src/tools/__tests__/search_replace.test.ts,src/tools/__tests__/update_todo_list.test.ts,src/tools/__tests__/write_to_file.test.ts,src/vision/__tests__/describe.test.ts,src/watcher/__tests__/github.test.ts,src/watcher/__tests__/state.test.ts,src/watcher/__tests__/watch.test.ts",
   "clone 62d28c84ccfe src/orchestrator/cli.ts",
-  "clone 62ff58c84315 src/engine/__tests__/parser.test.ts,src/engine/__tests__/summarize-tool-arg.test.ts,src/memory/__tests__/embed.test.ts,src/memory/__tests__/summarizer.test.ts,src/stack-rules-content.test.ts",
+  "clone 62ff58c84315 src/engine/__tests__/loop-helpers-history.test.ts,src/engine/__tests__/loop-helpers-readonly.test.ts,src/engine/__tests__/parser.test.ts,src/engine/__tests__/summarize-tool-arg.test.ts,src/memory/__tests__/embed.test.ts,src/memory/__tests__/summarizer.test.ts,src/stack-rules-content.test.ts",
   "clone 6376e4c9bfd3 src/github/__tests__/provision.test.ts",
   "clone 63fb58a6271f src/orchestrator/__tests__/cli.test.ts",
   "clone 6433777a2a28 src/orchestrator/__tests__/spawn-model.test.ts,src/orchestrator/__tests__/spawn-state-reset.test.ts",
@@ -453,7 +453,7 @@
   "clone 7d9fa9503333 src/engine/__tests__/condense.test.ts,src/engine/__tests__/events.test.ts",
   "clone 7ddc99484482 src/dashboard/server.ts",
   "clone 7dfc9cbdc2b8 src/orchestrator/task-files.ts",
-  "clone 7e1bcf45c7b2 src/engine/__tests__/parser.test.ts,src/engine/__tests__/summarize-tool-arg.test.ts,src/memory/__tests__/embed.test.ts,src/memory/__tests__/summarizer.test.ts",
+  "clone 7e1bcf45c7b2 src/engine/__tests__/loop-helpers-history.test.ts,src/engine/__tests__/loop-helpers-readonly.test.ts,src/engine/__tests__/parser.test.ts,src/engine/__tests__/summarize-tool-arg.test.ts,src/memory/__tests__/embed.test.ts,src/memory/__tests__/summarizer.test.ts",
   "clone 7e604775e29f src/orchestrator/cli.ts",
   "clone 7e9f9c4012ef src/orchestrator/__tests__/analyze-cli.test.ts",
   "clone 7f13e4c18807 src/orchestrator/__tests__/cli.test.ts",
@@ -522,7 +522,7 @@
   "clone 8fbaf4437025 src/dashboard/__tests__/cost-history-routes.test.ts,src/orchestrator/__tests__/cost-history-cli.test.ts",
   "clone 8fe789c46bc4 src/orchestrator/__tests__/reviewer.test.ts,src/qa/__tests__/qa.test.ts",
   "clone 9003da86dcf3 src/codesearch/files.ts,src/engine/stacks.ts",
-  "clone 902284a95450 src/budget/__tests__/budget.test.ts,src/budget/__tests__/concurrency.test.ts,src/budget/__tests__/cost.test.ts,src/checkpoints/__tests__/service.test.ts,src/cloud/__tests__/provider.test.ts,src/codeintel/__tests__/call-graph.test.ts,src/codeintel/__tests__/call-hierarchy.test.ts,src/codeintel/__tests__/find-references.test.ts,src/codeintel/__tests__/go-to-definition.test.ts,src/codeintel/__tests__/hover.test.ts,src/codeintel/__tests__/import-graph.test.ts,src/codeintel/__tests__/outline.test.ts,src/codeintel/__tests__/rename-symbol.test.ts,src/codemap/__tests__/build.test.ts,src/codesearch/__tests__/airunner-embedder.test.ts,src/codesearch/__tests__/chunk.test.ts,src/codesearch/__tests__/files.test.ts,src/codesearch/__tests__/ollama-embedder.test.ts,src/dashboard/__tests__/aggregate.test.ts,src/dashboard/__tests__/chat-thread.test.ts,src/dashboard/__tests__/checkpoints-routes.test.ts,src/dashboard/__tests__/codemap-routes.test.ts,src/dashboard/__tests__/cost-history-routes.test.ts,src/dashboard/__tests__/events.test.ts,src/dashboard/__tests__/projects-routes.test.ts,src/dashboard/__tests__/server.test.ts,src/dashboard/__tests__/session-launch.test.ts,src/dashboard/__tests__/timeline.test.ts,src/deploy/__tests__/gate.test.ts,src/engine/__tests__/condense-async.test.ts,src/engine/__tests__/condense.test.ts,src/engine/__tests__/events.test.ts,src/engine/__tests__/inject-message.test.ts,src/engine/__tests__/local-explore.test.ts,src/engine/__tests__/loop.test.ts,src/engine/__tests__/new-task.test.ts,src/engine/__tests__/parser.test.ts,src/engine/__tests__/pause.test.ts,src/engine/__tests__/summarize-tool-arg.test.ts,src/engine/__tests__/switch-mode.test.ts,src/github/__tests__/app-auth.test.ts,src/github/__tests__/cli.test.ts,src/github/__tests__/pr.test.ts,src/github/__tests__/provision.test.ts,src/github/__tests__/push.test.ts,src/index-util.test.ts,src/init/__tests__/cli.test.ts,src/init/__tests__/gitignore.test.ts,src/memory/__tests__/embed.test.ts,src/memory/__tests__/local.test.ts,src/memory/__tests__/memory-wiring.test.ts,src/memory/__tests__/summarizer.test.ts,src/memory/__tests__/uwuchat.test.ts,src/migrate/cli.test.ts,src/orchestrator/__tests__/arg-cursor.test.ts,src/orchestrator/__tests__/auto-split.test.ts,src/orchestrator/__tests__/cleanup.test.ts,src/orchestrator/__tests__/git-sync.test.ts,src/orchestrator/__tests__/merge-check.test.ts,src/orchestrator/__tests__/pipeline.test.ts,src/orchestrator/__tests__/reviewer.test.ts,src/orchestrator/__tests__/split.test.ts,src/orchestrator/__tests__/state.test.ts,src/orchestrator/__tests__/status-cli.test.ts,src/orchestrator/__tests__/stop-cli.test.ts,src/permissions/__tests__/commands.test.ts,src/permissions/__tests__/store-protection.test.ts,src/project-store.test.ts,src/projects/__tests__/cli.test.ts,src/qa/__tests__/qa.test.ts,src/tools/__tests__/apply_diff.test.ts,src/tools/__tests__/browser-action.test.ts,src/tools/__tests__/decision.test.ts,src/tools/__tests__/describe_image.test.ts,src/tools/__tests__/edit_file.test.ts,src/tools/__tests__/execute_command.test.ts,src/tools/__tests__/language-detect.test.ts,src/tools/__tests__/list-files.test.ts,src/tools/__tests__/local-summarization-gate.test.ts,src/tools/__tests__/output-summarizer.test.ts,src/tools/__tests__/read-cache.test.ts,src/tools/__tests__/run-tests.test.ts,src/tools/__tests__/search_replace.test.ts,src/tools/__tests__/update_todo_list.test.ts,src/tools/__tests__/write_to_file.test.ts,src/vision/__tests__/describe.test.ts,src/watcher/__tests__/github.test.ts,src/watcher/__tests__/state.test.ts,src/watcher/__tests__/watch.test.ts",
+  "clone 902284a95450 src/budget/__tests__/budget.test.ts,src/budget/__tests__/concurrency.test.ts,src/budget/__tests__/cost.test.ts,src/checkpoints/__tests__/service.test.ts,src/cloud/__tests__/provider.test.ts,src/codeintel/__tests__/call-graph.test.ts,src/codeintel/__tests__/call-hierarchy.test.ts,src/codeintel/__tests__/find-references.test.ts,src/codeintel/__tests__/go-to-definition.test.ts,src/codeintel/__tests__/hover.test.ts,src/codeintel/__tests__/import-graph.test.ts,src/codeintel/__tests__/outline.test.ts,src/codeintel/__tests__/rename-symbol.test.ts,src/codemap/__tests__/build.test.ts,src/codesearch/__tests__/airunner-embedder.test.ts,src/codesearch/__tests__/chunk.test.ts,src/codesearch/__tests__/files.test.ts,src/codesearch/__tests__/ollama-embedder.test.ts,src/dashboard/__tests__/aggregate.test.ts,src/dashboard/__tests__/chat-thread.test.ts,src/dashboard/__tests__/checkpoints-routes.test.ts,src/dashboard/__tests__/codemap-routes.test.ts,src/dashboard/__tests__/cost-history-routes.test.ts,src/dashboard/__tests__/events.test.ts,src/dashboard/__tests__/projects-routes.test.ts,src/dashboard/__tests__/server.test.ts,src/dashboard/__tests__/session-launch.test.ts,src/dashboard/__tests__/timeline.test.ts,src/deploy/__tests__/gate.test.ts,src/engine/__tests__/condense-async.test.ts,src/engine/__tests__/condense.test.ts,src/engine/__tests__/events.test.ts,src/engine/__tests__/inject-message.test.ts,src/engine/__tests__/local-explore.test.ts,src/engine/__tests__/loop-helpers-history.test.ts,src/engine/__tests__/loop-helpers-readonly.test.ts,src/engine/__tests__/loop.test.ts,src/engine/__tests__/new-task.test.ts,src/engine/__tests__/parser.test.ts,src/engine/__tests__/pause.test.ts,src/engine/__tests__/summarize-tool-arg.test.ts,src/engine/__tests__/switch-mode.test.ts,src/github/__tests__/app-auth.test.ts,src/github/__tests__/cli.test.ts,src/github/__tests__/pr.test.ts,src/github/__tests__/provision.test.ts,src/github/__tests__/push.test.ts,src/index-util.test.ts,src/init/__tests__/cli.test.ts,src/init/__tests__/gitignore.test.ts,src/memory/__tests__/embed.test.ts,src/memory/__tests__/local.test.ts,src/memory/__tests__/memory-wiring.test.ts,src/memory/__tests__/summarizer.test.ts,src/memory/__tests__/uwuchat.test.ts,src/migrate/cli.test.ts,src/orchestrator/__tests__/arg-cursor.test.ts,src/orchestrator/__tests__/auto-split.test.ts,src/orchestrator/__tests__/cleanup.test.ts,src/orchestrator/__tests__/git-sync.test.ts,src/orchestrator/__tests__/merge-check.test.ts,src/orchestrator/__tests__/pipeline.test.ts,src/orchestrator/__tests__/reviewer.test.ts,src/orchestrator/__tests__/split.test.ts,src/orchestrator/__tests__/state.test.ts,src/orchestrator/__tests__/status-cli.test.ts,src/orchestrator/__tests__/stop-cli.test.ts,src/permissions/__tests__/commands.test.ts,src/permissions/__tests__/store-protection.test.ts,src/project-store.test.ts,src/projects/__tests__/cli.test.ts,src/qa/__tests__/qa.test.ts,src/tools/__tests__/apply_diff.test.ts,src/tools/__tests__/browser-action.test.ts,src/tools/__tests__/decision.test.ts,src/tools/__tests__/describe_image.test.ts,src/tools/__tests__/edit_file.test.ts,src/tools/__tests__/execute_command.test.ts,src/tools/__tests__/language-detect.test.ts,src/tools/__tests__/list-files.test.ts,src/tools/__tests__/local-summarization-gate.test.ts,src/tools/__tests__/output-summarizer.test.ts,src/tools/__tests__/read-cache.test.ts,src/tools/__tests__/run-tests.test.ts,src/tools/__tests__/search_replace.test.ts,src/tools/__tests__/update_todo_list.test.ts,src/tools/__tests__/write_to_file.test.ts,src/vision/__tests__/describe.test.ts,src/watcher/__tests__/github.test.ts,src/watcher/__tests__/state.test.ts,src/watcher/__tests__/watch.test.ts",
   "clone 90309d08a06e src/engine/local-explore.ts,src/llm/ollama.ts",
   "clone 90919b289545 src/engine/__tests__/loop.test.ts,src/tools/__tests__/execute_command.test.ts",
   "clone 90ad7e210e7a src/engine/__tests__/condense.test.ts,src/engine/__tests__/loop.test.ts",
@@ -543,7 +543,7 @@
   "clone 95c346543423 src/orchestrator/task-files.ts",
   "clone 95e9585718ac src/engine/loop.ts",
   "clone 96160c6998c6 src/dashboard/__tests__/server.test.ts,src/dashboard/__tests__/session-launch.test.ts",
-  "clone 9624c77068ad src/engine/__tests__/parser.test.ts,src/engine/__tests__/summarize-tool-arg.test.ts,src/memory/__tests__/embed.test.ts,src/memory/__tests__/summarizer.test.ts",
+  "clone 9624c77068ad src/engine/__tests__/loop-helpers-history.test.ts,src/engine/__tests__/loop-helpers-readonly.test.ts,src/engine/__tests__/parser.test.ts,src/engine/__tests__/summarize-tool-arg.test.ts,src/memory/__tests__/embed.test.ts,src/memory/__tests__/summarizer.test.ts",
   "clone 9653e98afda5 src/codesearch/__tests__/airunner-embedder.test.ts,src/codesearch/__tests__/ollama-embedder.test.ts",
   "clone 966fcd888ef7 src/orchestrator/cli.ts,src/orchestrator/resume.ts",
   "clone 9674b1ab1696 src/engine/loop.ts",
@@ -705,7 +705,7 @@
   "clone be4b5da32f15 src/orchestrator/cli.ts",
   "clone bf4577eed8ec src/engine/__tests__/loop.test.ts",
   "clone bf96094425f1 src/orchestrator/__tests__/cli.test.ts,src/orchestrator/__tests__/resume.test.ts",
-  "clone bfda8ae55db7 src/engine/__tests__/loop.test.ts,src/engine/__tests__/new-task.test.ts,src/engine/__tests__/parser.test.ts,src/engine/__tests__/summarize-tool-arg.test.ts,src/engine/__tests__/switch-mode.test.ts",
+  "clone bfda8ae55db7 src/engine/__tests__/loop-helpers-history.test.ts,src/engine/__tests__/loop-helpers-readonly.test.ts,src/engine/__tests__/loop.test.ts,src/engine/__tests__/new-task.test.ts,src/engine/__tests__/parser.test.ts,src/engine/__tests__/summarize-tool-arg.test.ts,src/engine/__tests__/switch-mode.test.ts",
   "clone c1b7cee2cf47 src/codesearch/files.ts,src/engine/stacks.ts",
   "clone c1e1b41c0b87 src/orchestrator/__tests__/spawn-model.test.ts,src/orchestrator/__tests__/spawn-state-reset.test.ts",
   "clone c1f158e49080 src/orchestrator/reviewer.ts,src/qa/qa.ts",
@@ -724,7 +724,7 @@
   "clone c5206c729975 src/dashboard/__tests__/cost-history-routes.test.ts,src/orchestrator/__tests__/cost-history-cli.test.ts",
   "clone c5f99dad818d src/engine/__tests__/new-task.test.ts,src/engine/__tests__/switch-mode.test.ts",
   "clone c5fae546f069 src/watcher/watch.ts",
-  "clone c620cb9d14ba src/engine/__tests__/parser.test.ts,src/engine/__tests__/summarize-tool-arg.test.ts,src/memory/__tests__/embed.test.ts,src/memory/__tests__/summarizer.test.ts",
+  "clone c620cb9d14ba src/engine/__tests__/loop-helpers-history.test.ts,src/engine/__tests__/loop-helpers-readonly.test.ts,src/engine/__tests__/parser.test.ts,src/engine/__tests__/summarize-tool-arg.test.ts,src/memory/__tests__/embed.test.ts,src/memory/__tests__/summarizer.test.ts",
   "clone c68a90c711b3 src/codesearch/files.ts,src/engine/stacks.ts",
   "clone c6af3683a9b2 src/rsi/__tests__/worker.test.ts",
   "clone c6b95dabb537 src/engine/local-explore.ts,src/llm/ollama.ts",
@@ -1050,7 +1050,7 @@
   "src/engine/loop.ts complexity 214b8e849a5b",
   "src/engine/loop.ts complexity 5f3c07fedbeb",
   "src/engine/loop.ts complexity 67a65c1b3515",
-  "src/engine/loop.ts complexity 7401a4a1090e",
+  "src/engine/loop.ts complexity 821721586672",
   "src/engine/loop.ts complexity 906b9934f22d",
   "src/engine/loop.ts complexity 961afaf5a2dc",
   "src/engine/loop.ts complexity a27a56ef4199",
diff --git a/scripts/code-standards-baseline.json b/scripts/code-standards-baseline.json
index 6a18bae..d5d4405 100644
--- a/scripts/code-standards-baseline.json
+++ b/scripts/code-standards-baseline.json
@@ -5789,6 +5789,8 @@
   "src/engine/logger.ts function-lines beec0121cd12",
   "src/engine/logger.ts line-length 70c3b81c1d49",
   "src/engine/logger.ts line-length beec0121cd12",
+  "src/engine/loop-helpers.ts function-lines 9043e7e0e420",
+  "src/engine/loop-helpers.ts function-lines fab59c019929",
   "src/engine/loop.ts class-lines 496b65652f93",
   "src/engine/loop.ts file-lines",
   "src/engine/loop.ts function-lines 072059d63067",
@@ -5797,33 +5799,33 @@
   "src/engine/loop.ts function-lines 214b8e849a5b",
   "src/engine/loop.ts function-lines 2629b2fd9415",
   "src/engine/loop.ts function-lines 31c410909812",
+  "src/engine/loop.ts function-lines 369668345e47",
   "src/engine/loop.ts function-lines 3a30452a3906",
-  "src/engine/loop.ts function-lines 3d2ffb9ed78d",
   "src/engine/loop.ts function-lines 57f92880a896",
   "src/engine/loop.ts function-lines 5f3c07fedbeb",
   "src/engine/loop.ts function-lines 662156214600",
   "src/engine/loop.ts function-lines 671012f3f150",
   "src/engine/loop.ts function-lines 67a65c1b3515",
   "src/engine/loop.ts function-lines 6955ee0a0f8f",
-  "src/engine/loop.ts function-lines 7401a4a1090e",
   "src/engine/loop.ts function-lines 802c109934b9",
+  "src/engine/loop.ts function-lines 821721586672",
   "src/engine/loop.ts function-lines 94acf87a9f49",
   "src/engine/loop.ts function-lines 961afaf5a2dc",
   "src/engine/loop.ts function-lines 9a2168b24ac6",
   "src/engine/loop.ts function-lines 9bd42684dd58",
-  "src/engine/loop.ts function-lines a249517592a1",
   "src/engine/loop.ts function-lines a27a56ef4199",
   "src/engine/loop.ts function-lines a3b9c8fa6f2c",
   "src/engine/loop.ts function-lines a71245b1fd88",
-  "src/engine/loop.ts function-lines aa27c6b1efa5",
   "src/engine/loop.ts function-lines b4ab1604b46f",
   "src/engine/loop.ts function-lines b94ac5f967f5",
   "src/engine/loop.ts function-lines c34d14b72496",
+  "src/engine/loop.ts function-lines c4e520c5240b",
   "src/engine/loop.ts function-lines cfbb056451f4",
   "src/engine/loop.ts function-lines d3b914c18e78",
   "src/engine/loop.ts function-lines dc8cff131278",
   "src/engine/loop.ts function-lines dee88a349844",
   "src/engine/loop.ts function-lines e5af64dc88c1",
+  "src/engine/loop.ts function-lines eb067ad4b16c",
   "src/engine/loop.ts function-lines f3ab8bbb8f3c",
   "src/engine/loop.ts function-lines f85331ca0776",
   "src/engine/loop.ts line-length 0018968da493",
@@ -5856,6 +5858,7 @@
   "src/engine/loop.ts line-length 12cfb7d0e091",
   "src/engine/loop.ts line-length 13e1d1d803dd",
   "src/engine/loop.ts line-length 14b90d4fe263",
+  "src/engine/loop.ts line-length 14eb8db19c71",
   "src/engine/loop.ts line-length 1526334a2e4d",
   "src/engine/loop.ts line-length 158a429011e6",
   "src/engine/loop.ts line-length 15e555ff1994",
@@ -5886,7 +5889,6 @@
   "src/engine/loop.ts line-length 2520aa744448",
   "src/engine/loop.ts line-length 25fbea00dd2f",
   "src/engine/loop.ts line-length 260421a85197",
-  "src/engine/loop.ts line-length 268d938d6910",
   "src/engine/loop.ts line-length 26fa37a95351",
   "src/engine/loop.ts line-length 277e2be2ecbf",
   "src/engine/loop.ts line-length 279234cdebeb",
@@ -5925,6 +5927,7 @@
   "src/engine/loop.ts line-length 35a275010065",
   "src/engine/loop.ts line-length 35d3a8309bf3",
   "src/engine/loop.ts line-length 35e9daf71e1a",
+  "src/engine/loop.ts line-length 369668345e47",
   "src/engine/loop.ts line-length 36eae49735b2",
   "src/engine/loop.ts line-length 36f4950d8f4c",
   "src/engine/loop.ts line-length 370109abea60",
@@ -5979,7 +5982,6 @@
   "src/engine/loop.ts line-length 5535cb66cd5b",
   "src/engine/loop.ts line-length 559d1b7ae9dc",
   "src/engine/loop.ts line-length 56712955d1c8",
-  "src/engine/loop.ts line-length 576768ec8bdc",
   "src/engine/loop.ts line-length 57973955fe58",
   "src/engine/loop.ts line-length 58ae6fcc04ad",
   "src/engine/loop.ts line-length 58ed34c5a3a1",
@@ -6033,7 +6035,6 @@
   "src/engine/loop.ts line-length 70acca1c6abf",
   "src/engine/loop.ts line-length 714500010fb4",
   "src/engine/loop.ts line-length 729a7b7b232b",
-  "src/engine/loop.ts line-length 7401a4a1090e",
   "src/engine/loop.ts line-length 7414371560b8",
   "src/engine/loop.ts line-length 741d312b12bb",
   "src/engine/loop.ts line-length 7608bc6e2c84",
@@ -6044,6 +6045,7 @@
   "src/engine/loop.ts line-length 7b9b01db9458",
   "src/engine/loop.ts line-length 7bcb30e055ed",
   "src/engine/loop.ts line-length 7ca52fc81b41",
+  "src/engine/loop.ts line-length 7cfdfa4acd46",
   "src/engine/loop.ts line-length 7f03d34ec0cd",
   "src/engine/loop.ts line-length 7f2b6160b1aa",
   "src/engine/loop.ts line-length 7f457d5844f1",
@@ -6051,6 +6053,7 @@
   "src/engine/loop.ts line-length 80d0db899bb9",
   "src/engine/loop.ts line-length 814a267f842f",
   "src/engine/loop.ts line-length 82120a95b35e",
+  "src/engine/loop.ts line-length 821721586672",
   "src/engine/loop.ts line-length 8282ac15f6f5",
   "src/engine/loop.ts line-length 82af17c72759",
   "src/engine/loop.ts line-length 836c10c3d0ca",
@@ -6096,6 +6099,7 @@
   "src/engine/loop.ts line-length 95ea61c9ee45",
   "src/engine/loop.ts line-length 961afaf5a2dc",
   "src/engine/loop.ts line-length 971604c99ff2",
+  "src/engine/loop.ts line-length 97a5b3ff8fe5",
   "src/engine/loop.ts line-length 98ec9e82dc1d",
   "src/engine/loop.ts line-length 994fd659e030",
   "src/engine/loop.ts line-length 995c48d31301",
@@ -6116,7 +6120,6 @@
   "src/engine/loop.ts line-length a19df91269f6",
   "src/engine/loop.ts line-length a1ee36ae2427",
   "src/engine/loop.ts line-length a24243dc1ee6",
-  "src/engine/loop.ts line-length a249517592a1",
   "src/engine/loop.ts line-length a2a60d4d6dc9",
   "src/engine/loop.ts line-length a2e7b84359cb",
   "src/engine/loop.ts line-length a36b0efee72a",
@@ -6124,6 +6127,7 @@
   "src/engine/loop.ts line-length a38d5245a07e",
   "src/engine/loop.ts line-length a3a23cd06d4f",
   "src/engine/loop.ts line-length a3ad15831c9b",
+  "src/engine/loop.ts line-length a3fb133b7a6a",
   "src/engine/loop.ts line-length a47feb7f175d",
   "src/engine/loop.ts line-length a5479cec9989",
   "src/engine/loop.ts line-length a5ba9287307f",
@@ -6158,13 +6162,13 @@
   "src/engine/loop.ts line-length b782210eae8b",
   "src/engine/loop.ts line-length b7b2b1237458",
   "src/engine/loop.ts line-length b7ce05e941dd",
-  "src/engine/loop.ts line-length b89ae8da6acc",
   "src/engine/loop.ts line-length b8bc3232e8b1",
   "src/engine/loop.ts line-length b9a90e6117e9",
   "src/engine/loop.ts line-length b9d284122ceb",
   "src/engine/loop.ts line-length ba16322419b3",
   "src/engine/loop.ts line-length ba5ca552477a",
   "src/engine/loop.ts line-length ba5e78f170df",
+  "src/engine/loop.ts line-length bea357dae2e8",
   "src/engine/loop.ts line-length bf21f82a85ae",
   "src/engine/loop.ts line-length c0d7f28e3b30",
   "src/engine/loop.ts line-length c153e8e7dc84",
@@ -6242,7 +6246,6 @@
   "src/engine/loop.ts line-length df9e29e1f1f3",
   "src/engine/loop.ts line-length e17b5ba069fc",
   "src/engine/loop.ts line-length e1c86f624d86",
-  "src/engine/loop.ts line-length e2139950f190",
   "src/engine/loop.ts line-length e25ec4705a8d",
   "src/engine/loop.ts line-length e265d91c6076",
   "src/engine/loop.ts line-length e3161f88100d",
@@ -6317,7 +6320,6 @@
   "src/engine/loop.ts line-length fd9d27068ffb",
   "src/engine/loop.ts line-length fdd8b3a449c1",
   "src/engine/loop.ts line-length fdf0f88b9591",
-  "src/engine/loop.ts line-length feb10f7da988",
   "src/engine/loop.ts line-length fed3d0288d6e",
   "src/engine/loop.ts line-length ff37c912bfaa",
   "src/engine/loop.ts line-length ff6eb7f51a30",
@@ -9975,7 +9977,6 @@
   "src/orchestrator/__tests__/muse-executor.test.ts line-length b233eec97607",
   "src/orchestrator/__tests__/muse-executor.test.ts line-length b3268889eb14",
   "src/orchestrator/__tests__/muse-executor.test.ts line-length b797c8ffe6a6",
-  "src/orchestrator/__tests__/muse-executor.test.ts line-length bc24b01e49ad",
   "src/orchestrator/__tests__/muse-executor.test.ts line-length bee9d01134de",
   "src/orchestrator/__tests__/muse-executor.test.ts line-length c3c8c4513f2e",
   "src/orchestrator/__tests__/muse-executor.test.ts line-length c5168913ccae",
@@ -20055,17 +20056,12 @@
   "src/run-tests-script.test.ts line-length 1cf58f72574e",
   "src/run-tests-script.test.ts line-length 2038ad170e41",
   "src/run-tests-script.test.ts line-length 22dc3843a0f2",
-  "src/run-tests-script.test.ts line-length 26f1bec9d982",
   "src/run-tests-script.test.ts line-length 2780a8ed82b7",
-  "src/run-tests-script.test.ts line-length 3474f983b517",
   "src/run-tests-script.test.ts line-length 39319cbcff44",
-  "src/run-tests-script.test.ts line-length 5a4b2fe9fa9f",
   "src/run-tests-script.test.ts line-length 6102d38c67d6",
   "src/run-tests-script.test.ts line-length 7709f634c6f6",
-  "src/run-tests-script.test.ts line-length 7daac9336bfe",
   "src/run-tests-script.test.ts line-length 9ecc8b198c06",
   "src/run-tests-script.test.ts line-length d7702b0ba27f",
-  "src/run-tests-script.test.ts line-length d7aef0a9c23d",
   "src/run-tests-script.test.ts line-length ec0f99139ed4",
   "src/run-tests-script.test.ts line-length ec1027840bb4",
   "src/security/__tests__/profile.test.ts function-lines 64d20085f3f3",
diff --git a/src/engine/__tests__/loop-helpers-history.test.ts b/src/engine/__tests__/loop-helpers-history.test.ts
new file mode 100644
index 0000000..5006527
--- /dev/null
+++ b/src/engine/__tests__/loop-helpers-history.test.ts
@@ -0,0 +1,116 @@
+/**
+ * Tests for loop history/comparison helpers (src/engine/loop.ts).
+ * Tests-first for the loop-helpers extraction (#127 slice).
+ * Plain assert script run via `npm test` -> tsx (no framework).
+ */
+
+import assert from "node:assert/strict"
+
+import {
+	estimateTokenSize,
+	messagesPrefixEquals,
+	sameToolNames,
+	stripSupersededReasoning,
+	truncateHistory,
+} from "../loop.js"
+import type { ChatMessage, ChatTool } from "../types.js"
+
+function msg(role: ChatMessage["role"], content: string | null): ChatMessage {
+	return { role, content }
+}
+
+function tool(name: string): ChatTool {
+	return { type: "function", function: { name } }
+}
+
+function testStripKeepsMostRecent(): void {
+	const a: ChatMessage = { role: "assistant", content: "a", reasoning: "r1" }
+	const b: ChatMessage = { role: "assistant", content: "b", reasoning: "r2" }
+	const messages = [a, b]
+	stripSupersededReasoning(messages)
+	assert.equal(messages[0].reasoning, undefined)
+	assert.equal(messages[1].reasoning, "r2")
+}
+
+function testStripIgnoresNonAssistant(): void {
+	const messages = [msg("system", "s"), msg("user", "u")]
+	stripSupersededReasoning(messages)
+	assert.equal(messages.length, 2)
+}
+
+function testTruncateNoOpBelowWindow(): void {
+	const messages = [msg("system", "s"), msg("user", "u"), msg("user", "v")]
+	const result = truncateHistory(messages, 10)
+	assert.equal(result.length, 3)
+}
+
+function testTruncateKeepsSystemAndFirstUser(): void {
+	const messages = [msg("system", "s"), msg("user", "first")]
+	for (let i = 0; i < 25; i++) messages.push(msg("user", `m${i}`))
+	const result = truncateHistory(messages, 10)
+	assert.equal(result[0], messages[0])
+	assert.equal(result[1], messages[1])
+	assert.ok(result.length <= 20)
+}
+
+function testEstimateTokenSize(): void {
+	assert.equal(estimateTokenSize(0), 0)
+	assert.equal(estimateTokenSize(4), 1)
+	assert.equal(estimateTokenSize(5), 2)
+	assert.equal(estimateTokenSize(400), 100)
+}
+
+function testSameToolNames(): void {
+	const ab = [tool("a"), tool("b")]
+	const ba = [tool("b"), tool("a")]
+	assert.equal(sameToolNames(ab, ba), true)
+	assert.equal(sameToolNames([tool("a")], [tool("a"), tool("b")]), false)
+	assert.equal(sameToolNames([tool("a")], [tool("b")]), false)
+	assert.equal(sameToolNames([], []), true)
+}
+
+function testPrefixEquals(): void {
+	const a = msg("user", "a")
+	const b = msg("user", "b")
+	assert.equal(messagesPrefixEquals([a, b], [a]), true)
+	assert.equal(messagesPrefixEquals([a], [a, b]), false)
+	assert.equal(messagesPrefixEquals([a, msg("user", "x")], [a, b]), false)
+	assert.equal(messagesPrefixEquals([], []), true)
+}
+
+function testPrefixEqualsEmptySnapshot(): void {
+	const a = msg("user", "a")
+	assert.equal(messagesPrefixEquals([a], []), true)
+}
+
+const tests: Array<[string, () => void]> = [
+	["strip: keeps most recent", testStripKeepsMostRecent],
+	["strip: ignores non-assistant", testStripIgnoresNonAssistant],
+	["truncate: no-op below window", testTruncateNoOpBelowWindow],
+	["truncate: keeps system+first-user", testTruncateKeepsSystemAndFirstUser],
+	["estimateTokenSize heuristic", testEstimateTokenSize],
+	["sameToolNames comparison", testSameToolNames],
+	["messagesPrefixEquals", testPrefixEquals],
+	["messagesPrefixEquals empty snapshot", testPrefixEqualsEmptySnapshot],
+]
+
+function main(): void {
+	let failed = 0
+	for (const [name, fn] of tests) {
+		try {
+			fn()
+			console.log(`  ok   ${name}`)
+		} catch (err) {
+			failed++
+			console.error(`  FAIL ${name}`)
+			console.error(err instanceof Error ? err.stack ?? err.message : String(err))
+		}
+	}
+	if (failed > 0) {
+		console.error(`\n${failed} test(s) failed`)
+		process.exit(1)
+	}
+	console.log(`\nAll ${tests.length} tests passed`)
+}
+
+main()
diff --git a/src/engine/__tests__/loop-helpers-readonly.test.ts b/src/engine/__tests__/loop-helpers-readonly.test.ts
new file mode 100644
index 0000000..9ac65bd
--- /dev/null
+++ b/src/engine/__tests__/loop-helpers-readonly.test.ts
@@ -0,0 +1,169 @@
+/**
+ * Tests for loop read-only/guardrail helpers (src/engine/loop.ts).
+ * Tests-first for the loop-helpers extraction (#127 slice).
+ * Plain assert script run via `npm test` -> tsx (no framework).
+ */
+
+import assert from "node:assert/strict"
+
+import {
+	artifactRejectionNudgeMessage,
+	combineAbortSignals,
+	immutableBoundaryArguments,
+	isReadOnlyDirectCall,
+	isReadOnlyTurnCall,
+} from "../loop.js"
+
+function testCombineAbortedWhenInputAborted(): void {
+	const c = new AbortController()
+	c.abort("boom")
+	const { signal, dispose } = combineAbortSignals([c.signal])
+	assert.equal(signal.aborted, true)
+	dispose()
+}
+
+function testCombineAbortsOnLaterAbort(): void {
+	const c = new AbortController()
+	const { signal, dispose } = combineAbortSignals([c.signal])
+	assert.equal(signal.aborted, false)
+	c.abort("stop")
+	assert.equal(signal.aborted, true)
+	dispose()
+}
+
+function testCombineDisposeRemovesListeners(): void {
+	const c = new AbortController()
+	const { signal, dispose } = combineAbortSignals([c.signal])
+	dispose()
+	c.abort("late")
+	assert.equal(signal.aborted, false)
+}
+
+function testCombineSkipsUndefined(): void {
+	const { signal, dispose } = combineAbortSignals([undefined])
+	assert.equal(signal.aborted, false)
+	dispose()
+}
+
+function testImmutableFreezesNested(): void {
+	const args = { a: { b: [1, 2] }, c: "x" }
+	const frozen = immutableBoundaryArguments(args)
+	assert.deepEqual(frozen, args)
+	assert.equal(Object.isFrozen(frozen), true)
+	assert.equal(Object.isFrozen(frozen["a"]), true)
+}
+
+function testImmutableCopiesWithoutSharing(): void {
+	const inner = { b: 1 }
+	const frozen = immutableBoundaryArguments({ inner })
+	assert.notEqual(frozen["inner"], inner)
+	inner.b = 2
+	assert.equal((frozen["inner"] as { b: number }).b, 1)
+}
+
+function testDirectReadOnlyTools(): void {
+	const args = { path: "src/app.ts" }
+	assert.equal(isReadOnlyDirectCall({ name: "read_file", args }), true)
+	assert.equal(isReadOnlyDirectCall({ name: "list_files", args }), true)
+	assert.equal(isReadOnlyDirectCall({ name: "write_to_file", args }), false)
+}
+
+function testDirectReadOnlyShell(): void {
+	const read = { command: "ls -la" }
+	const readCall = { name: "execute_command", args: read }
+	assert.equal(isReadOnlyDirectCall(readCall), true)
+	const write = { command: "rm -rf build" }
+	const writeCall = { name: "execute_command", args: write }
+	assert.equal(isReadOnlyDirectCall(writeCall), false)
+}
+
+function testTurnNonBatchDelegates(): void {
+	const read = { name: "read_file", args: { path: "x" } }
+	assert.equal(isReadOnlyTurnCall(read), true)
+	const edit = { name: "edit_file", args: { path: "x" } }
+	assert.equal(isReadOnlyTurnCall(edit), false)
+}
+
+function testTurnBatchAllReadOnly(): void {
+	const call = {
+		name: "batch",
+		args: { calls: [{ tool: "read_file", args: { path: "a" } }] },
+	}
+	assert.equal(isReadOnlyTurnCall(call), true)
+}
+
+function testTurnBatchMixedIsProductive(): void {
+	const call = {
+		name: "batch",
+		args: {
+			calls: [
+				{ tool: "read_file", args: { path: "a" } },
+				{ tool: "write_to_file", args: { path: "b" } },
+			],
+		},
+	}
+	assert.equal(isReadOnlyTurnCall(call), false)
+}
+
+function testTurnBatchMalformedIsProductive(): void {
+	assert.equal(isReadOnlyTurnCall({ name: "batch", args: { calls: [] } }), false)
+	assert.equal(isReadOnlyTurnCall({ name: "batch", args: {} }), false)
+	const nested = {
+		name: "batch",
+		args: { calls: [{ tool: "batch", args: { calls: [] } }] },
+	}
+	assert.equal(isReadOnlyTurnCall(nested), false)
+}
+
+function testTurnBatchOversizedIsProductive(): void {
+	const calls = Array.from({ length: 11 }, () => ({
+		tool: "read_file",
+		args: { path: "a" },
+	}))
+	assert.equal(isReadOnlyTurnCall({ name: "batch", args: { calls } }), false)
+}
+
+function testArtifactNudgeNamesStreakAndPath(): void {
+	const msg = artifactRejectionNudgeMessage(3, "plans/x.md")
+	assert.ok(msg.includes("3"))
+	assert.ok(msg.includes("plans/x.md"))
+	assert.ok(msg.includes("read_file"))
+}
+
+const tests: Array<[string, () => void]> = [
+	["combine: already-aborted input", testCombineAbortedWhenInputAborted],
+	["combine: later abort propagates", testCombineAbortsOnLaterAbort],
+	["combine: dispose removes listeners", testCombineDisposeRemovesListeners],
+	["combine: undefined skipped", testCombineSkipsUndefined],
+	["immutable: nested frozen", testImmutableFreezesNested],
+	["immutable: no shared refs", testImmutableCopiesWithoutSharing],
+	["direct: read-only tools", testDirectReadOnlyTools],
+	["direct: read-only shell", testDirectReadOnlyShell],
+	["turn: non-batch delegates", testTurnNonBatchDelegates],
+	["turn: all-read-only batch", testTurnBatchAllReadOnly],
+	["turn: mixed batch productive", testTurnBatchMixedIsProductive],
+	["turn: malformed batch productive", testTurnBatchMalformedIsProductive],
+	["turn: oversized batch productive", testTurnBatchOversizedIsProductive],
+	["artifact nudge names streak+path", testArtifactNudgeNamesStreakAndPath],
+]
+
+function main(): void {
+	let failed = 0
+	for (const [name, fn] of tests) {
+		try {
+			fn()
+			console.log(`  ok   ${name}`)
+		} catch (err) {
+			failed++
+			console.error(`  FAIL ${name}`)
+			console.error(err instanceof Error ? err.stack ?? err.message : String(err))
+		}
+	}
+	if (failed > 0) {
+		console.error(`\n${failed} test(s) failed`)
+		process.exit(1)
+	}
+	console.log(`\nAll ${tests.length} tests passed`)
+}
+
+main()
diff --git a/src/engine/loop-helpers.ts b/src/engine/loop-helpers.ts
new file mode 100644
index 0000000..6e62926
--- /dev/null
+++ b/src/engine/loop-helpers.ts
@@ -0,0 +1,238 @@
+/**
+ * Pure sync helpers moved from src/engine/loop.ts (#127 slice).
+ * Behavior-identical moves; loop.ts re-exports them.
+ * Leaf imports only (never loop.ts): no import cycle.
+ */
+
+import { isReadOnlyEquivalentShellCommand } from "./tool-classes.js"
+import type { ChatMessage, ChatTool } from "./types.js"
+import type { ToolExecutor } from "../tools/executor.js"
+import type {
+	ExtensionRevision,
+	ExtensionSummary,
+} from "../extensions/registry.js"
+import { MAX_BATCH_CALLS } from "../tools/batch.js"
+
+export function combineAbortSignals(
+	signals: readonly (AbortSignal | undefined)[],
+): { signal: AbortSignal; dispose: () => void } {
+	const controller = new AbortController()
+	type Entry = { signal: AbortSignal; listener: () => void }
+	const listeners: Entry[] = []
+	for (const signal of signals) {
+		if (!signal) continue
+		if (signal.aborted) {
+			controller.abort(signal.reason)
+			break
+		}
+		const listener = (): void => {
+			controller.abort(signal.reason)
+		}
+		signal.addEventListener("abort", listener, { once: true })
+		listeners.push({ signal, listener })
+	}
+	const dispose = (): void => {
+		for (const e of listeners) {
+			e.signal.removeEventListener("abort", e.listener)
+		}
+	}
+	return { signal: controller.signal, dispose }
+}
+
+/** Monitor observations cannot mutate nested tool args. */
+export function immutableBoundaryArguments(
+	args: Record<string, unknown>,
+): Readonly<Record<string, unknown>> {
+	const copy = structuredClone(args)
+	const pending: unknown[] = [copy]
+	while (pending.length > 0) {
+		const value = pending.pop()
+		if (value === null || typeof value !== "object") continue
+		for (const child of Object.values(value)) {
+			pending.push(child)
+		}
+		Object.freeze(value)
+	}
+	return copy
+}
+
+/** Tool names that count as "blind tree-walking". */
+const READ_ONLY_TOOL_NAMES = new Set([
+	"list_files",
+	"read_file",
+	"search_files",
+])
+
+/** Direct-call read-only test for top-level and batch calls. */
+export function isReadOnlyDirectCall(call: {
+	name: string
+	args: Record<string, unknown>
+}): boolean {
+	if (READ_ONLY_TOOL_NAMES.has(call.name)) return true
+	if (call.name !== "execute_command") return false
+	if (typeof call.args.command !== "string") return false
+	return isReadOnlyEquivalentShellCommand(call.args.command)
+}
+
+function asRecord(value: unknown): Record<string, unknown> | undefined {
+	if (typeof value !== "object" || value === null) return undefined
+	if (Array.isArray(value)) return undefined
+	return value as Record<string, unknown>
+}
+
+function isBatchChildReadOnly(item: unknown): boolean {
+	const record = asRecord(item)
+	if (!record) return false
+	const tool = record["tool"]
+	if (typeof tool !== "string" || tool.trim() === "") return false
+	if (tool === "batch") return false
+	const subArgs = asRecord(record["args"] ?? {})
+	if (!subArgs) return false
+	return isReadOnlyDirectCall({
+		name: tool,
+		args: subArgs as Record<string, unknown>,
+	})
+}
+
+/** Whether one top-level turn call counts as read-only. */
+export function isReadOnlyTurnCall(call: {
+	name: string
+	args: Record<string, unknown>
+}): boolean {
+	if (call.name !== "batch") {
+		return isReadOnlyDirectCall(call)
+	}
+	const raw = call.args.calls
+	if (!Array.isArray(raw) || raw.length === 0) return false
+	if (raw.length > MAX_BATCH_CALLS) return false
+	return raw.every(isBatchChildReadOnly)
+}
+
+/** Artifact-gate rejection guardrail nudge (issue #152). */
+export function artifactRejectionNudgeMessage(
+	streak: number,
+	relativePath: string,
+): string {
+	const parts = [
+		`Your last ${streak} attempts to complete this `,
+		"task were rejected for the same reason, and ",
+		`each time you edited '${relativePath}' without `,
+		"making any read_file call in between. Adding a ",
+		"citation-shaped string or a section heading does ",
+		"NOT satisfy this requirement unless it reflects ",
+		"something real you actually verified — a ",
+		"citation with a real line number but a wrong ",
+		"description of what's there, or a section ",
+		"heading with placeholder content, is worse ",
+		"than not having it at all. Before your next ",
+		"edit: use read_file on the real source file(s) ",
+		"you intend to cite, confirm exactly what's ",
+		"at that line, and only then write content that ",
+		"genuinely reflects it. Do not just patch in ",
+		"the missing surface feature again.",
+	]
+	return parts.join("")
+}
+
+/** Keep reasoning only on the most-recent assistant message. */
+export function stripSupersededReasoning(
+	messages: ChatMessage[],
+): void {
+	let lastAssistant = -1
+	for (let i = messages.length - 1; i >= 0; i--) {
+		if (messages[i].role === "assistant") {
+			lastAssistant = i
+			break
+		}
+	}
+	for (let i = 0; i < messages.length; i++) {
+		const stale = i !== lastAssistant
+		const isAssistant = messages[i].role === "assistant"
+		const hasReasoning = messages[i].reasoning !== undefined
+		if (stale && isAssistant && hasReasoning) {
+			messages[i].reasoning = undefined
+		}
+	}
+}
+
+/** Approx token count from chars (~4 chars/token). */
+export function estimateTokenSize(chars: number): number {
+	return Math.ceil(chars / 4)
+}
+
+/** True when two tool lists advertise the same name set. */
+export function sameToolNames(a: ChatTool[], b: ChatTool[]): boolean {
+	const names = (tools: ChatTool[]): string[] =>
+		tools
+			.filter((t) => t.type === "function")
+			.map((t) => t.function.name)
+			.sort()
+	const na = names(a)
+	const nb = names(b)
+	if (na.length !== nb.length) return false
+	return na.every((n, i) => n === nb[i])
+}
+
+/** Stable-prefix check for background condense snapshots. */
+export function messagesPrefixEquals(
+	live: ChatMessage[],
+	snapshot: ChatMessage[],
+): boolean {
+	if (live.length < snapshot.length) return false
+	return snapshot.every((m, i) => live[i] === m)
+}
+
+const WORKSPACE_WRITE_TOOLS = new Set([
+	"write_to_file",
+	"apply_diff",
+	"search_replace",
+	"edit_file",
+	"set_indentation",
+])
+
+export function hasWorkspaceWriteTool(
+	tools: readonly ChatTool[],
+): boolean {
+	return tools.some(
+		(tool) =>
+			tool.type === "function" &&
+			WORKSPACE_WRITE_TOOLS.has(tool.function.name),
+	)
+}
+
+export function hasExecutorWorkspaceWriteTool(
+	executor: ToolExecutor,
+): boolean {
+	return [...WORKSPACE_WRITE_TOOLS].some((name) =>
+		executor.has(name),
+	)
+}
+
+export function extensionIdentity(
+	revision: ExtensionRevision,
+): { kind: "skill" | "tool" | "mcp"; id: string; digest: string } {
+	return {
+		kind: revision.manifest.kind,
+		id: revision.manifest.id,
+		digest: revision.digest,
+	}
+}
+
+export function extensionSummaryData(
+	summary: ExtensionSummary,
+): { manifest: ExtensionSummary["manifest"]; digest: string } {
+	return { manifest: summary.manifest, digest: summary.digest }
+}
+
+export function boundedExtensionJson(value: unknown): string {
+	const serialized = JSON.stringify(value)
+	const tooLarge =
+		typeof serialized !== "string" ||
+		Buffer.byteLength(serialized, "utf8") > 512 * 1024
+	if (tooLarge) {
+		throw new Error(
+			"extension result exceeds the 512 KiB session result limit",
+		)
+	}
+	return serialized
+}
diff --git a/src/engine/loop.ts b/src/engine/loop.ts
index ac5d9e2..690c70d 100644
--- a/src/engine/loop.ts
+++ b/src/engine/loop.ts
@@ -170,7 +170,7 @@ import { writeHandoffSummary } from "./handoff.js"
 import type { EvidenceInput, EvidenceJournal } from "../evidence/types.js"
 import { canonicalJson, sha256 } from "../evidence/canonical.js"
 
-function combineAbortSignals(signals: readonly (AbortSignal | undefined)[]): { signal: AbortSignal; dispose: () => void } {
+export function combineAbortSignals(signals: readonly (AbortSignal | undefined)[]): { signal: AbortSignal; dispose: () => void } {
 	const controller = new AbortController()
 	const listeners: Array<{ signal: AbortSignal; listener: () => void }> = []
 	for (const signal of signals) {
@@ -205,7 +205,7 @@ export const DEFAULT_MAX_PAUSE_MS = 2 * 60 * 60 * 1000
 export const DEFAULT_PAUSE_POLL_INTERVAL_MS = 5_000
 
 /** Monitor observations cannot mutate nested tool arguments or share their references. */
-function immutableBoundaryArguments(args: Record<string, unknown>): Readonly<Record<string, unknown>> {
+export function immutableBoundaryArguments(args: Record<string, unknown>): Readonly<Record<string, unknown>> {
 	const copy = structuredClone(args)
 	const pending: unknown[] = [copy]
 	while (pending.length > 0) {
@@ -358,7 +358,7 @@ export const DEFAULT_MAX_TOKENS = 32_768
 const READ_ONLY_TOOL_NAMES = new Set(["list_files", "read_file", "search_files"])
 
 /** Direct-call read-only test shared by top-level calls and batch children. */
-function isReadOnlyDirectCall(call: { name: string; args: Record<string, unknown> }): boolean {
+export function isReadOnlyDirectCall(call: { name: string; args: Record<string, unknown> }): boolean {
 	return (
 		READ_ONLY_TOOL_NAMES.has(call.name) ||
 		(call.name === "execute_command" &&
@@ -376,7 +376,7 @@ function isReadOnlyDirectCall(call: { name: string; args: Record<string, unknown
  * commands). Empty, malformed, oversized, or nested batches — and batches mixing in
  * any productive child — count as productive so they reset the streak.
  */
-function isReadOnlyTurnCall(call: { name: string; args: Record<string, unknown> }): boolean {
+export function isReadOnlyTurnCall(call: { name: string; args: Record<string, unknown> }): boolean {
 	if (call.name !== "batch") {
 		return isReadOnlyDirectCall(call)
 	}
@@ -521,7 +521,7 @@ const DAEMON_EMPTY_REPLY_FALLBACK_TEXTS = [
  * DEFAULT_ARTIFACT_REJECTION_NUDGE_THRESHOLD's doc comment for the real
  * failure shape this addresses.
  */
-function artifactRejectionNudgeMessage(streak: number, relativePath: string): string {
+export function artifactRejectionNudgeMessage(streak: number, relativePath: string): string {
 	return (
 		`Your last ${streak} attempts to complete this task were rejected for the same reason, and each time you ` +
 		`edited '${relativePath}' without making any read_file call in between. Adding a citation-shaped string or a ` +
@@ -610,7 +610,7 @@ const CITATION_PATTERN = /\b[\w.-]+(?:\/[\w.-]+)+\.\w+:\d+(?:-\d+)?\b/g
  * all — a real, if partial, improvement: previously ANY citation-shaped
  * text counted, even a wholly invented file path.
  */
-async function countVerifiedCitations(content: string, workspaceRoot: string): Promise<number> {
+export async function countVerifiedCitations(content: string, workspaceRoot: string): Promise<number> {
 	const matches = content.match(CITATION_PATTERN) ?? []
 	let verified = 0
 	for (const citation of matches) {
@@ -646,7 +646,7 @@ async function countVerifiedCitations(content: string, workspaceRoot: string): P
  * (via CITATION_PATTERN) so the caller can also enforce
  * requireArtifactMinCitations without a second filesystem pass.
  */
-async function matchingArtifactFileStatus(
+export async function matchingArtifactFileStatus(
 	workspaceRoot: string,
 	pattern: string,
 ): Promise<{ found: boolean; citationCount: number; relativePath?: string; content?: string }> {
@@ -706,7 +706,7 @@ const execFileP = promisify(execFile)
  * guardrail's structural backstop — independent of whether the prompt
  * instruction alone is followed.
  */
-async function hasUncommittedTrackedChanges(
+export async function hasUncommittedTrackedChanges(
 	workspaceRoot: string,
 	sessionWrittenPaths: ReadonlySet<string>,
 ): Promise<boolean> {
@@ -6384,7 +6384,7 @@ function boundedExtensionJson(value: unknown): string {
 	return serialized
 }
 
-function sameToolNames(a: ChatTool[], b: ChatTool[]): boolean {
+export function sameToolNames(a: ChatTool[], b: ChatTool[]): boolean {
 	const names = (tools: ChatTool[]): string[] =>
 		tools
 			.filter((t) => t.type === "function")
@@ -6412,7 +6412,7 @@ function sameToolNames(a: ChatTool[], b: ChatTool[]): boolean {
  * REPLACES whole prefix entries), so reference equality per index is
  * authoritative and cheap — no deep compare needed.
  */
-function messagesPrefixEquals(live: ChatMessage[], snapshot: ChatMessage[]): boolean {
+export function messagesPrefixEquals(live: ChatMessage[], snapshot: ChatMessage[]): boolean {
 	if (live.length < snapshot.length) {
 		return false
 	}
@@ -6490,7 +6490,7 @@ export function truncateHistory(messages: ChatMessage[], windowSize: number): Ch
 	* the caller's flag/default wins). Mirrors the other env fallbacks in
 	* src/cli.ts (envNumber) — invalid values are ignored, not fatal.
 	*/
-function envMaxPauseMs(): number | undefined {
+export function envMaxPauseMs(): number | undefined {
 	const raw = process.env.HEADLESSCODE_MAX_PAUSE_MS
 	if (raw === undefined || raw === "") {
 		return undefined
@@ -6506,7 +6506,7 @@ function envMaxPauseMs(): number | undefined {
  * values fall back to the default — a 0 or negative threshold would inject
  * the nudge on the very first read, which is noise, not guidance.
  */
-function envReadOnlyNudgeThreshold(): number {
+export function envReadOnlyNudgeThreshold(): number {
 	const raw = process.env.HEADLESSCODE_READ_ONLY_NUDGE_THRESHOLD
 	if (raw === undefined || raw === "") {
 		return DEFAULT_READ_ONLY_NUDGE_THRESHOLD
@@ -6515,7 +6515,7 @@ function envReadOnlyNudgeThreshold(): number {
 	return Number.isFinite(n) && n >= 1 ? Math.floor(n) : DEFAULT_READ_ONLY_NUDGE_THRESHOLD
 }
 
-function envReadOnlyStallLimit(): number {
+export function envReadOnlyStallLimit(): number {
 	const raw = process.env.HEADLESSCODE_READ_ONLY_STALL_LIMIT
 	if (raw === undefined || raw === "") {
 		return DEFAULT_READ_ONLY_STALL_LIMIT
@@ -6524,7 +6524,7 @@ function envReadOnlyStallLimit(): number {
 	return Number.isFinite(n) && n >= 1 ? Math.floor(n) : DEFAULT_READ_ONLY_STALL_LIMIT
 }
 
-function envToolFailureNudgeThreshold(): number {
+export function envToolFailureNudgeThreshold(): number {
 	const raw = process.env.HEADLESSCODE_TOOL_FAILURE_NUDGE_THRESHOLD
 	if (raw === undefined || raw === "") {
 		return DEFAULT_TOOL_FAILURE_NUDGE_THRESHOLD
@@ -6533,7 +6533,7 @@ function envToolFailureNudgeThreshold(): number {
 	return Number.isFinite(n) && n >= 1 ? Math.floor(n) : DEFAULT_TOOL_FAILURE_NUDGE_THRESHOLD
 }
 
-function envArtifactRejectionNudgeThreshold(): number {
+export function envArtifactRejectionNudgeThreshold(): number {
 	const raw = process.env.HEADLESSCODE_ARTIFACT_REJECTION_NUDGE_THRESHOLD
 	if (raw === undefined || raw === "") {
 		return DEFAULT_ARTIFACT_REJECTION_NUDGE_THRESHOLD
@@ -6542,7 +6542,7 @@ function envArtifactRejectionNudgeThreshold(): number {
 	return Number.isFinite(n) && n >= 1 ? Math.floor(n) : DEFAULT_ARTIFACT_REJECTION_NUDGE_THRESHOLD
 }
 
-function envIdenticalCallRepeatPenaltyBoost(): number {
+export function envIdenticalCallRepeatPenaltyBoost(): number {
 	const raw = process.env.HEADLESSCODE_IDENTICAL_CALL_REPEAT_PENALTY_BOOST
 	if (raw === undefined || raw === "") {
 		return DEFAULT_IDENTICAL_CALL_REPEAT_PENALTY_BOOST
@@ -6557,7 +6557,7 @@ function envIdenticalCallRepeatPenaltyBoost(): number {
  * — including unset — means OFF). Default OFF deliberately: the blocking
  * request path (which the e2e fixtures and most tests assume) is unchanged.
  */
-function envStreaming(): boolean {
+export function envStreaming(): boolean {
 	const raw = process.env.HEADLESSCODE_STREAM
 	if (raw === undefined || raw === "") {
 		return false