Conciseness

Dense conventions with no basic-concept padding (e.g., "Prefer assertions on observable conditions over fixed sleeps" assumes competence throughout), but the locator section states the same rule twice in adjacent paragraphs ("Use an exact accessible name or scope the query to the intended region" then "Prefer an exact accessible name or a scoped query over `.first()`"), which could be merged.

Actionability

Fully executable, copy-paste-ready examples: a complete `it('calls onClick', ...)` test with imports, `act(() => { button.element().focus() })`, and a rerender/detach check, plus a decision table mapping contract to assertion and paired Avoid/Prefer polling snippets — the common cases are covered.

Workflow Clarity

Situation-based guidance is unambiguous with explicit feedback loops ("When an act warning occurs, check that manual updates use RTL's `act`..."; "If a browser action unexpectedly fails... investigate its visibility, enabled state"), but there is no end-to-end write-run-verify sequence — running and verifying tests is delegated to the external testing guide.

Progressive Disclosure

A well-sectioned single file with one clearly signaled one-level reference ("Read [the testing guide](../../../contributor-docs/testing.md) for strategy, environment setup, and commands"), but no bundle files exist (no references/, scripts/, or assets/) and that referenced path points outside the skill bundle and does not resolve, so the skill's one dependency is unverifiable.

Specificity

Names a precise domain and several actions — "authoring, modifying, reviewing, or debugging Primer React component and hook tests in Vitest browser mode" — but the verbs are lifecycle actions rather than the concrete testing capabilities the skill actually covers (assertion selection, locators, act handling), so coverage has minor gaps.

Completeness

The 'when' is fully explicit with concrete positive and negative triggers ("Use when authoring...", "Do not use for Node/SSR tests..."), but the 'what' is conveyed only through the trigger activity — there is no separate statement of what the skill provides. Not 3 because 'when' is explicit and specific rather than weakly implied.

Trigger Term Quality

Good natural-term coverage: "component and hook tests", "Vitest browser mode", "Primer React", "Playwright visual or accessibility tests" are phrases a repo user would say. It is not 5 because common variants like "React Testing Library", "RTL", or "unit tests" are absent.

Distinctiveness Conflict Risk

A clear niche ("Primer React", "Vitest browser mode") with active disambiguation of the nearest neighbors ("Do not use for Node/SSR tests, standalone Playwright visual or accessibility tests, or component implementation without test changes"), giving minimal conflict risk.