Conciseness

Roughly eight lean lines with zero padding: no library explainers, no concept recaps, no filler. Every sentence either routes ('Read the testing policy for the package that owns the changed tests') or sets behavior, assuming Claude's competence throughout.

Actionability

Concrete, executable guidance: exact file paths ('web/docs/test.md', 'packages/dify-ui/docs/testing.md'), an unambiguous ownership rule, and specific behavioral directives ('report the contract verified and any material verification gap'). Falls short of 5 only because the actual validation commands are deferred to the referenced docs rather than given inline — a minor gap for a router skill.

Workflow Clarity

The single routing step is unambiguous (package under test → its owner doc), and verification is explicitly mandated twice ('including its validation commands', 'report the contract verified and any material verification gap'). Not 5 because the validation checkpoints themselves are not sequenced here — they live in the external policy docs; not 3 because validation is required and the sequence has no gaps for this simple skill.

Progressive Disclosure

Under 50 lines with no bundle files needed; sections are well organized and the two references are clearly signaled, exactly one level deep, and each annotated with what it owns ('test boundaries, environments, and commands'). Meets the rubric's simple-skill exception for a top score.

Specificity

Names several concrete actions — 'writing or changing Vitest or React Testing Library tests', 'frontend test strategy', 'evaluation of an existing strategy' — with only minor coverage gaps (e.g. running or debugging tests is not mentioned). Not 5 because the action list is not comprehensive; not 3 because it goes beyond 1-2 actions.

Completeness

The 'when' is explicit and multi-conditioned ('Use when writing or changing... or when the user explicitly requests frontend test strategy'), but the 'what' — that the skill routes to package-level testing policy — is only implied by naming the domain rather than clearly stated. Not 5 because the 'what' is not explicit; not 3 because the 'when' is strong and the 'what' is identifiable.

Trigger Term Quality

Good keyword coverage including 'Vitest', 'React Testing Library', 'frontend test strategy', 'Python tests', 'Cucumber/Playwright E2E', and path-based triggers ('web/', 'packages/dify-ui/'), plus exclusion triggers. A few natural variations users might say ('unit tests', 'component tests', 'RTL') are missing, so it does not reach the comprehensive-synonym level of 5.

Distinctiveness Conflict Risk

Clear niche (Vitest/RTL tests under two named directories) with explicit negative triggers ('Do not use for frontend code-review-only requests, general testability discussion, Python tests, or Cucumber/Playwright E2E') that disambiguate it from adjacent skills. Minimal conflict risk — matches the 5 anchor.