Conciseness

Every line is operational — 'MAX 3 per session, reserved for evidence', 'a uid from a prior snapshot, not a CSS selector', 'an arrow function string, not a raw expression'. No padding and no explanation of concepts Claude already knows; nothing needs trimming, so it fits anchor 5 rather than anchor 4.

Actionability

Fully executable specifics: 'evaluate_script — { function: "() => ..." }' with copy-paste assertion expressions ('!!document.querySelector(...)', 'new URL(location.href).searchParams.toString()'), exact argument shapes for navigate_page, resize_page, and the performance trace pair, plus a concrete edge-case URL ('?q=nonexistent'). Specific examples cover all the common cases, matching anchor 5 rather than anchor 4's 'minor gaps'.

Workflow Clarity

The workflow is an unambiguous sequence (Navigate → wait_for → assert → interactions → edge case → console check → re-run at every breakpoint) with explicit validation checkpoints and a genuine feedback loop: 'any error: fix source, rebuild, reload, restart from navigate', reinforced by 'Every test must pass before reporting the result'. Explicit validation and error recovery match anchor 5, not anchor 4 where checkpoints are merely present.

Progressive Disclosure

The body is under 50 lines, well organized into focused sections (Context budget, Tools, Workflow, Regression re-test), and needs no bundle files; project-specific detail is correctly deferred to a clearly signaled one-level reference ('.opencastle/stack/testing-config.md'). This matches the simple-skill exception for a top score.

Specificity

It lists six concrete actions — 'navigation, DOM snapshots, scripted assertions, responsive checks, console and performance traces' — exceeding the four-action anchor-5 example, and leaves no meaningful capability unspecified. Not 4: coverage is comprehensive within the browser-testing domain rather than gapped.

Completeness

It explicitly answers both 'what' ('Browser testing through the Chrome DevTools MCP: navigation, DOM snapshots, scripted assertions...') and 'when' with three concrete trigger phrases ('Use when verifying a UI change in Chrome, checking breakpoints, or reading console errors'). This matches anchor 5 exactly; not 4 because the when-clause is explicit and specific rather than vague.

Trigger Term Quality

Natural user phrases are present ('verifying a UI change in Chrome', 'reading console errors', 'checking breakpoints'), but common variations a user would actually say — 'screenshot', 'mobile layout', 'test the page' — are missing. Good-but-incomplete keyword coverage matches anchor 4; not 5 (no synonym breadth) and not 3 (coverage is clearly good, not partial).

Distinctiveness Conflict Risk

'Chrome DevTools MCP' pins a clear niche, and the triggers are Chrome/browser-specific ('verifying a UI change in Chrome'), so overlap with generic document or data skills is minimal. Matches anchor 5's 'clear niche with distinct triggers'; not 4 because no closely related skill would capture these triggers first.