Conciseness

The body assumes Claude's competence throughout — no basic-concept explanations — and nearly every sentence carries project-specific constraints ('a wrong config value produces a tidy diff, a green build and no behaviour change, which no gate can fail on'). A few rationale passages run long (the complexity-rating justification, the NEW-FEAT.md blackboard paragraph) and could be trimmed, which is the 4 anchor's 'minor instances of over-explanation' rather than the uniformly lean 5.

Actionability

Fully executable throughout: the pre-flight capability probe, 'gh issue create' with a complete body heredoc, both the worktree and in-place branch recipes with exact commands including the 'git config branch.<branch>.gh-merge-base' trick for stacked PRs — copy-paste ready with placeholders only where user input is genuinely required, matching the 5 anchor.

Workflow Clarity

'Four things, in this order — each depends on the one before' plus Steps 0–4 gives an explicit sequence; validation is equally explicit — the capability probe runs 'once, before Step 0' rather than failing per step, the 'When a gate cannot run' section defines fallback and honesty rules, and stress-plan is a hard gate ('every finding closed, before a line of code is written'). This is the 5 anchor's clear sequence with explicit validation and error-recovery, not 4's 'minor validation gaps'.

Progressive Disclosure

The body is a well-organized overview that delegates cleanly: 'The routing table is references/skills-routing.md' points to a real one-level-deep bundle file, and detailed material (rate-complexity, stress-plan, prep-pr, wiki/observability/overview.md) is referenced rather than inlined. Minor gaps keep it at 4 — the observability naming rules and issue-body conventions are long enough to live in a reference file, and skills-routing.md is the only bundle file carrying that load.

Specificity

The description lists multiple concrete actions — 'taking or opening its GitHub issue, cutting the branch (a worktree on the local bare repo, an in-place branch on the remote environment) and producing the implementation plan, including the wiki pages the work will make stale and its observability plan' — comprehensive coverage of the workflow, matching the 5 anchor rather than 4 (no meaningful coverage gaps).

Completeness

It explicitly answers both questions: 'Use when starting a piece of feature or fix work in this repository' is a concrete trigger phrase, and the what follows immediately with the full action list — the exact shape of the 5 anchor, not merely the both-present-but-could-be-sharper 4 anchor.

Trigger Term Quality

Natural phrases like 'feature or fix work', 'GitHub issue', 'cutting the branch' and 'implementation plan' give good keyword coverage, but project-specific jargon ('bare repo', 'tracker finding', 'observability plan') dominates and common synonyms ('new feature', 'start work', 'bugfix') are absent — noticeably above the midpoint but short of the comprehensive-synonym coverage of the 5 anchor.

Distinctiveness Conflict Risk

A clear start-of-work niche with distinct triggers ('starting a piece of feature or fix work', 'turning a tracker finding into a branch without publishing it'), but the sibling end-of-work skill prep-pr covers the other half of the same pipeline, creating the minor overlap with a closely related skill that defines the 4 anchor rather than 5.