Conciseness

The body is dense with novel Hunk-specific facts and assumes competence (e.g., "Transforms must preserve `metadata` (spreading a file does)"), with no explanation of concepts Claude already knows. It is not a 5 because reference-grade minutiae such as the workspace-status bounded-collection limits ("20,000 changed paths, 100 sibling rows, five operations...") are inlined and could be deferred to the linked sources.

Actionability

Guidance is copy-paste ready and covers the common cases: a complete hello-extension example, the touchpoint table mapping goals to exact API calls, exact dev-dependency and tsconfig settings for typechecking ("add `hunkdiff` as a dev dependency and run `tsc --noEmit`... `\"jsxImportSource\": \"@opentui/react\"`"), and concrete commands like `hunk diff --extension ./my-ext` and `bun run test:integration`.

Workflow Clarity

A clear sequence is stated up front ("use the table below to find the call, then read the linked material before writing code"), followed by a numbered verification ladder ordered by cost (typecheck → unit test → PTY integration → hand to user → `--no-extensions` triage) with explicit validation steps, and a symptom-to-cause feedback loop in "If it does not load". This matches the explicit-validation-with-error-recovery anchor, not merely the most-checkpoints level of 4.

Progressive Disclosure

The skill ships no bundle files; its "Sources of truth — read before writing" table clearly signals one-level-deep references into the Hunk repo's docs, types, and examples, and sections are well organized. It falls short of the top anchor because substantial API-grade detail (the workspace-status capability contract and CLI handler rules) is inlined in a ~370-line SKILL.md rather than split into a bundled reference, though structure and signaling are clearly above the could-be-better-organized level of 3.

Specificity

The description enumerates the full capability surface concretely: "hiding or reordering reviewed files, docked panes, alternate file views, commands and key bindings, dialogs, workspace writes, themes, syntax languages, VCS backends, lifecycle events". This is comprehensive coverage of specific actions, not minor-gapped as the score-4 anchor requires.

Completeness

It explicitly answers both parts: what ("Maps the `hunkdiff/extension` authoring surface..." with a concrete capability list) and when ("Use when writing, debugging, or installing a Hunk extension, or when a request asks Hunk itself to behave differently"), plus an explicit exclusion clause. Both are concrete and fully explicit, matching the top anchor rather than the could-be-more-specific level of 4.

Trigger Term Quality

"writing, debugging, or installing a Hunk extension" and "a request asks Hunk itself to behave differently" capture natural user phrasings, alongside surface terms like themes, key bindings, and VCS backends. It falls short of the score-5 anchor because common synonyms such as "plugin" or "customize Hunk" are absent, but it clearly exceeds the some-keywords-missing level of 3.

Distinctiveness Conflict Risk

The niche is distinct (Hunk extension authoring) and it explicitly disambiguates the closest sibling: "Not for reviewing a diff in a live session — that is hunk-review". Minimal conflict risk, matching the clear-niche anchor rather than the minor-overlap level of 4.