A Claude Code plugin marketplace from Darling Data.
/plugin marketplace add erikdarlingdata/claude-plugins
Teaches Claude to read a SQL Server execution plan and say what is actually slow, and why.
/plugin install sqlserver-query-plans@erikdarling
Point Claude at a .sqlplan file and ask. The skill is model-invoked — you do not
need to call it explicitly.
The hard part of plan analysis is not spotting operators. It is knowing which numbers mean what they appear to mean. This plugin is built mostly out of the conclusions that sound authoritative and are wrong:
- Cost percentages are estimates in every plan, including actual plans. Nothing recomputes them after execution. The 97%-cost operator is routinely not the slow one, and an operator shown at 0% can consume the entire runtime.
- Row-mode operator times are cumulative. Ranking operators by raw
ActualElapsedmsranks them by depth and always crowns the root node. Batch mode reports standalone times. Exchange operators report times that are close to meaningless. EstimateRowsis per-execution;ActualRowsis a total. Without dividing byActualExecutions, the inner side of every nested loop looks catastrophically underestimated when it may have estimated perfectly.- Missing-index requests are hints, not DDL. Equality columns come out in
arbitrary order, existing indexes are ignored, and the
Impactfigure is a percentage of an estimated cost. - A scan is not a defect and a seek is not a virtue. Judge by rows touched and time spent.
It also ships scripts/extract.py, which flattens a .sqlplan into a compact
digest. This is not a convenience:
.sqlplanfiles are UTF-16, sogrepsilently matches nothing and reports no error. A negative result fromgrepon a plan file is worthless.- Some plans are UTF-8 bytes that still declare
encoding="utf-16", because they were opened and re-saved. Strict XML parsers reject them. - A trivial two-table join is 120 KB. Real plans run to megabytes. Reading one into context wastes the context and still misses things.
The extractor handles the encoding, computes correct self-time attribution
(subtracting children in row mode, within a thread rather than across threads in
parallel plans, and not at all in batch mode), normalizes cardinality per
execution, and recognizes the optimizer's default-guess selectivity fingerprints.
--node N drills into a single operator; --sql recovers full statement text.
Requires Python 3 (standard library only). Without it, the skill degrades to a
documented grep-based fallback and says plainly what it cannot determine.
This plugin also works in GitHub Copilot CLI,
which reads the same SKILL.md and plugin.json format.
copilot plugin marketplace add erikdarlingdata/claude-plugins
copilot plugin install sqlserver-query-plans@erikdarling
Or add just the skill, without the marketplace:
/skills add ./plugins/sqlserver-query-plans/skills/query-plan-analysis
As in Claude Code, the skill is model-invoked: point Copilot at a .sqlplan and ask.
This repository is also a pi package: the root
package.json declares every plugins/*/skills and plugins/*/extensions
directory, and pi reads the same SKILL.md format the other
two harnesses do. Install straight from git — no marketplace step:
pi install git:github.com/erikdarlingdata/claude-plugins
As everywhere else, the skill is model-invoked: point pi at a .sqlplan and ask.
Your machine restarts for updates with a dozen pi sessions open; this brings them all back with one command, as terminal tabs, in their original directories, with full history:
pi-resume-sessions
An extension (auto-loaded by the install above) records every open interactive
session; the pi-resume-sessions script reopens the interrupted ones — Ghostty
tabs on macOS, tmux anywhere. Sessions you quit deliberately (Ctrl+D, /quit)
stay closed; sessions killed by a reboot, a closed window, or a crash come
back. Idle-time filters keep abandoned sessions from resurrecting.
The script needs a one-time symlink onto your PATH, and macOS needs a one-time
Automation permission — see
plugins/pi-session-resume/README.md
for both, plus the design notes. This one is pi-only: Claude Code and Copilot
CLI don't load pi extensions.
Background subagents only report back when they finish — nothing wakes the
orchestrator while one wedges on a giant grep or balloons from 200k to 2M
tokens. This extension (auto-loaded by the install above) polls every running
subagent's live vitals — tokens, context %, tool uses, turns, wall clock,
compactions — and batches nearby threshold crossings into one compact
orchestrator check-in. Full structured records persist outside LLM context;
per-agent and fleet-wide rate limits keep the watchdog from becoming its own
token amplifier. Two orchestrator postures: guide (assess with judgment) and
strict (thresholds are budgets — wrap up by default, one evidence-cited
extension max). Optional automatic hard stop handles the truly wedged, with
the outcome reported from the RPC reply rather than assumed. An optional exact
model invariant hard-stops any top-level child that bypasses the manager's
pre-spawn model policy. The CLI surfaces also identify each child's effective
model and thinking level.
Humans get a /watchdog panel (vitals, manual check-ins, steering, hard
stop) plus /watchdog help | status | config | reload — config edits apply
live, no session restart. See
plugins/pi-subagent-watchdog/README.md
for signals, modes, and design notes. Requires the
pi-subagents extension; pi-only
for the same reason as above.
Token-budget guardrails for multi-agent setups, built after an overnight orchestration burned through its usage limit (95% of the spend came at more than 150k context). It has three pieces:
guardrails.md: the written rules for fan-out caps, model tiers, context discipline, session length and ranking.- A context-wall extension, loaded only into subagents through their agent files. It tells the child its own size at 150k and 200k. At 250k it refuses everything but git/gh and markdown writes, so the agent commits and reports instead of being aborted with its work lost.
- A
laneagent type for code-editing lanes: Sonnet, its own worktree, draft PRs, no fan-out tools.
The wall is deliberately not auto-loaded, because it would wall off your interactive session too. See
plugins/pi-subagent-guardrails/README.md for install and the
recommended watchdog and pi-subagents settings.
pi-setup-guide.md — a distilled ~15-minute setup for
pi written for Claude Code ex-pats: install, model/thinking
defaults, the trust model, a Claude-to-pi habit translation table, a
tested-together extension stack, full source for a few small
quality-of-life extensions (refusal fallback, tab-title status, ! command
wake-ups + autocomplete), how to point pi at years of accumulated Claude Code
memory instead of migrating it, and a troubleshooting section of the gotchas
that actually happened. The plugins in this repo (§11–§13 of the guide) slot
into that stack.
Built by Erik Darling at Darling Data. SQL Server consulting, training, and free tools: https://erikdarling.com
MIT