Conciseness

The body is mostly lean: severity tiers as a compact table, executable command blocks with one-line commentary, and no explanations of what OpenAPI is or how diffing works. A few spots could be trimmed — the repeated '(Per [oasdiff-readme][readme])' citation lines and the pact-comparison prose in 'Overview'/'Authoring' partially restate each other. This lands on anchor 4 ('efficient; minor instances of over-explanation that could be trimmed') rather than 5, and is clearly above anchor 3 because nothing teaches Claude concepts it already knows.

Actionability

Every section gives copy-paste-ready commands: `go install`/`docker pull` install, four `--format` invocations, a Docker run variant, `--fail-on` gate examples, a `jq` triage pipeline, and a complete GitHub Actions workflow with merge-base spec extraction and artifact upload. Example report output (text and JSON) is included so Claude knows what to expect. This matches anchor 5 ('fully executable; copy-paste ready; specific examples cover the common cases'), not 4, since there are no significant gaps.

Workflow Clarity

The sequence Install → Running (local/remote/Docker) → Reading the report → CI integration is coherent and each step builds on the prior. The exit code is explicitly established as the gate signal ('The exit code is the gate signal') and the CI workflow includes a real checkpoint ('if: always()' artifact upload plus `--fail-on ERR`). This is a read-only review tool, so the destructive/batch validation cap does not apply. It sits at anchor 4 rather than 5 because there is no explicit error-recovery loop (e.g., what to do when the gate fails besides the one `x-extensible-enum` mitigation) and no pre-flight verification step; it is above anchor 3 because the checkpoints that do exist are explicit, not implicit.

Progressive Disclosure

No bundle files exist (references/, scripts/, assets/ are absent), so all content is inline in SKILL.md, organized under clear headers (Overview, When to use, Install, Running, What counts as breaking, Reading the report, CI integration, References). External references are clearly signaled and one level deep via a link table. Anchor 4 fits: good structure, content mostly appropriately placed, with a minor gap — the ~35-line inline GitHub Actions workflow and the full JSON report example are borderline candidates for a references file that would keep SKILL.md as a pure overview. Not 5 because the body leans toward monolithic; not 3 because navigation is easy and nothing is buried.

Specificity

The description lists multiple concrete, specific actions with concrete artifacts: 'Diffs two OpenAPI versions for breaking changes (removed endpoints, deleted schemas, narrowed enums, response shape changes) using `oasdiff breaking`', 'severity-classifies the findings (ERR / WARN / INFO)', and 'gates CI with `--fail-on`'. Coverage of the skill's capability surface is comprehensive, matching the anchor for listing multiple specific concrete actions. Not 4 because there are no meaningful gaps in the action list; not below because nothing is generic or abstract.

Completeness

Both questions are explicitly answered: the 'what' is concrete ('Diffs two OpenAPI versions... severity-classifies the findings (ERR / WARN / INFO), and gates CI with `--fail-on`') and the 'when' is an explicit trigger clause ('Use when reviewing an OpenAPI spec change in a PR or on a release tag'). This matches anchor 5 exactly; it is above anchor 4 because the when-clause is explicit and specific rather than merely present.

Trigger Term Quality

Good natural-keyword coverage: users would plausibly say 'OpenAPI', 'breaking changes', 'spec change', 'PR', and 'release tag', all of which appear verbatim ('Use when reviewing an OpenAPI spec change in a PR or on a release tag'). A few natural terms are missing — most notably the common synonym 'Swagger', file extensions like 'openapi.yaml', and phrasings like 'API diff'. This matches anchor 4 ('good keyword coverage; a few natural terms missing') rather than 5's requirement of comprehensive synonyms and extensions, and is well above anchor 3's 'missing common variations'.

Distinctiveness Conflict Risk

The description carves a clear niche — OpenAPI spec diffing with a named tool (`oasdiff breaking`), severity tiers (ERR / WARN / INFO), and a CI gate flag — that no generic description would collide with. It even implicitly disambiguates from consumer-driven contract testing by framing the trigger around spec review in PRs. Minimal conflict risk; matches anchor 5 rather than 4's 'minor overlap risk with closely related skills'.