Conciseness

The body is lean and assumes Claude's competence: no explanation of what git or commits are, only project-specific rules ("Use nested subsystems with `/` when helpful", "Wrap lines at ~72 characters", "If `.jj` is present, use `jj` instead of `git"). Every token carries information Claude could not infer, matching 'Lean and efficient; every token earns its place'.

Actionability

Guidance is concrete and executable: an exact format template, specific rules (lowercase imperative subject under 60 chars, references as `#1234` on their own lines, ~72-char wrap), and a workflow with commands ("Run a diff", "use `jj` instead of `git`"). It falls short of a 5 only because there is no worked example commit message showing the style end-to-end.

Workflow Clarity

The Workflow section gives a clear, ordered sequence (check for `.jj`, run a diff, identify subsystem, identify references, draft, apply, "Don't push the commit") with a safety boundary at the end. It lacks explicit validation checkpoints (e.g., verifying the subject length or that the subsystem matches the diff), so it does not reach the explicit validate-and-recover level of a 5; a single commit is not a destructive/batch operation, so no cap applies.

Progressive Disclosure

This is a simple single-task skill with no bundle files (references/, scripts/, assets/ are absent) and no need for external references; all ~50 lines belong inline. Sections (Format, Rules with subsections, Workflow) are well-organized and easy to navigate, which per the simple-skill guidance earns a 5 with just well-organized sections.

Specificity

"Writes Git commit messages" names the domain and a single concrete action, matching the anchor 'Names domain and 1-2 concrete actions, but not comprehensive'. It does not list several actions (e.g., analyzing diffs, following project style, applying the commit), so it is not a 4.

Completeness

Both parts are present: 'what' ("Writes Git commit messages") and an explicit 'when' ("Activates when the user asks to write a commit message, draft a commit message, or similar"). The 'when' is explicit, but the 'what' is minimal (it omits that messages follow project style and that the skill applies the commit) and "or similar" is a vague catch-all, so it falls just short of the fully concrete what+when of a 5.

Trigger Term Quality

"write a commit message, draft a commit message" are natural phrases users would say, giving good keyword coverage. A few natural variants are missing (e.g., 'commit', 'git commit', 'commit msg'), which keeps it below the comprehensive synonym coverage of a 5.

Distinctiveness Conflict Risk

"Git commit messages" is a clear niche with distinct, specific triggers ('write a commit message', 'draft a commit message'), giving minimal conflict risk with other skills. It is far more specific than the 'minor overlap risk with closely related skills' of a 4.