# Ship A Detector > Author a hook or gate detector end to end: the seven defect kinds this repo keeps re-shipping, then the install, test, README, and inventory wiring a detector is not finished without. Trigger before writing or widening anything under engine/hooks/ or a scripts/check_*.py gate — a new PreToolUse/Stop/UserPromptSubmit hook, a new detector inside an existing hook, or a regex change to one that already ships. - Skill: `edbertchan/ship-a-detector` (Agent Skill, multi-file: 4 files) - Install (CLI): `npx skillmds@latest add edbertchan/ship-a-detector` - Raw SKILL.md: https://api.skillmd.com/api/skills/edbertchan/ship-a-detector/raw - Safety review: pending - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: EdbertChan (https://skillmd.com/u/edbertchan) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/edbertchan/ship-a-detector --- # ship-a-detector Use this before writing or widening a detector — a hook under `engine/hooks/`, or a CI gate under `scripts/check_*.py`. Both decide "does this input match the bad thing", and both break the same seven ways here. ## Why this exists Measured on this repo's own history: 65 of 185 merged PRs touch `engine/hooks/`, 13 of 28 hooks needed post-ship repair, and 37 PRs did nothing but repair a shipped detector. `diu-stop` took 8, `pr-schema-gate` 7, `wrong-check-reflect` 6, `scope-lock` 4. `gh-write-verification` hit two separate known kinds in three days (#322, #323, #324). None of those were new problems; each was a kind already fixed in another hook. ## The playbook Read and copy [playbooks/detector-lifecycle.md](playbooks/detector-lifecycle.md) before any task-specific work. It is a verbatim ordered list: paste all 20 steps into your todolist first, then work them. A step that does not apply stays in the list marked `skip: ` — deleting it is how a kind gets re-shipped. The same list covers both jobs. A new hook works every step. A widening of a shipped detector skips the wiring tail with reasons and still works the detection steps, because 37 of this repo's repair PRs were repairs of detection, not of wiring. ## Two rules that outrank the list - Every numbered step names the PRs that motivated it. If you add a step, it names its prior art or says "no known prior art" — a step invented from a guess is the thing this repo already tried. - The list ends by calling the installed `make-pr` skill. `make-pr` opens the PR; it does not own the install, README, or inventory steps. Those are steps 14–18 here, because that is measurably where this repo breaks: 10 of 31 hooks have no `docs/ecosystem.md` row, and 8 got theirs in a later PR.