Conciseness

The body is dense with host-specific semantics Claude cannot reliably recall (exit-code effects per event, timeout budgets, matcher evaluation rules, trust model), so nearly every table earns its tokens rather than re-teaching known concepts. It falls short of the top anchor because version-pinned observations ("Observed on Codex 0.159.2", "with rtk 0.50.0", "hyphens need v2.1.195+") sit inline in operational sections instead of a dedicated observations/deprecated section, and the 33-event table plus dual-host matcher tables could be trimmed of rarely-audited rows.

Actionability

Guidance is fully executable: a copy-paste Python shell-word resolver for command strings, exact discovery commands (`ls ~/.claude/settings.json ...`, `type codex; which -a codex`), a 10-point scoring rubric with per-criterion point splits, and concrete canary procedures (sample payload on stdin, scratch-repository comparison). Claude can execute every step without inventing commands.

Workflow Clarity

Seven sequenced steps each end in an explicit "Done when:" checkpoint, and validation is built in throughout: behavior canaries when static checks pass, re-validation after fixes, live canaries in a disposable git repository, and a hard guard requiring explicit user confirmation before any hook deletion. This is the anchor case for clear sequence with explicit validation and error-recovery feedback loops.

Progressive Disclosure

Section headers and the Claude/Codex split give the body real structure, but ~300 lines of reference-grade material (the 33-event table, handler-field and matcher tables for two hosts, timeout defaults) are inlined in SKILL.md with no references/ directory or any external files to offload detail to. This matches the anchor for 'content that should be separate is inline'; it is above level 2 because headers and organization are genuinely good, and below level 4 because there are no well-signaled reference files at all — the whole knowledge base loads on every invocation.

Specificity

The description lists multiple concrete actions — "Resolves each command, checks event names, handler types, matchers, exit-code and JSON decision strategy, and timeouts against each host's documented rules, then reviews hooks one by one" — with comprehensive coverage and named target files (settings.json, hooks.json, config.toml, plugin, skill or agent frontmatter). It matches the anchor for multiple specific concrete actions; the level-4 anchor ('minor gaps in coverage') fits worse since every audit activity is enumerated.

Completeness

It explicitly answers both questions: the 'what' is a full audit pipeline (validity, safety, correctness; command resolution; event/handler/matcher/timeout checks) and the 'when' is a concrete "Use when setting up hooks, debugging a hook... or doing a periodic hooks hygiene pass" clause with specific trigger phrases, matching the top anchor exactly.

Trigger Term Quality

It covers natural phrases users would actually say: "setting up hooks", "debugging a hook that never fires, never blocks, or hangs the agent", and "a periodic hooks hygiene pass", plus an explicit negative boundary ("Not for writing a new hook from scratch"). Trigger coverage is comprehensive with synonymous failure modes; the level-4 anchor ('a few natural terms missing') is too weak a fit.

Distinctiveness Conflict Risk

The niche is auditing hooks across Claude Code and Codex with hook-specific triggers (never fires, never blocks, hangs the agent), and the closing "Not for writing a new hook from scratch" boundary further reduces wrong-skill triggering. Mentions of settings.json/config.toml create only negligible overlap with generic config-editing skills; the clear niche with distinct triggers matches the top anchor.