Conciseness

Efficient and dense with commands, but a few tokens could be trimmed ("implemented in Zig" trivia, and the generic "Keep dependencies up to date; Bun and the ecosystem evolve quickly") — anchor 4's "minor instances of over-explanation". Not 5 because those few tokens don't earn their place.

Actionability

Fully executable, copy-paste-ready commands and code covering the common cases: `bun install --frozen-lockfile`, `bun run --env-file=.env dev`, `bun test --watch`, `Bun.file`/`Bun.serve` snippets, and `bun build ./src/index.ts --outdir=dist` — matches anchor 5 exactly. Not 4 because there are no gaps; the examples cover install, run, env, test, and server API.

Workflow Clarity

The migration sequence is concrete ("Replace `node script.js` with `bun run script.js`… Run `bun install` in place of `npm install`") with explicit decision rules (Prefer Bun / Prefer Node lists), but there is no verification checkpoint after migration (e.g. "run bun test to confirm parity") — anchor 4's "minor validation gaps". Not 5 because explicit validation steps are absent; not 3 because the sequence and decision points are clear, and there are no destructive or batch operations that would trigger the cap.

Progressive Disclosure

The skill is self-contained with no external references needed and clean, well-organized sections (When to Use / How It Works / Examples / Best Practices). Per the judging guideline, a short skill with no need for external references scores 5 on well-organized sections alone. Not 4 because there is no content that clearly belongs in a separate bundle file.

Specificity

Lists several specific roles ("runtime, package manager, bundler, and test runner", "migration notes, and Vercel support") with only minor coverage gaps. Not 5 because these are role nouns rather than concrete operations like the top anchor's action verbs; not 3 because coverage goes well beyond 1-2 actions.

Completeness

The "what" is clear ("Bun as runtime, package manager, bundler, and test runner") but the "when" is only weakly implied via "When to choose Bun vs Node" — there is no explicit 'Use when...' clause, which per the judging guidelines caps completeness at 3. Not 4 because anchor 4 requires an explicit if imperfect 'when' statement.

Trigger Term Quality

Natural terms users would say ("Bun", "Node", "Vercel", "migration") with good coverage, matching anchor 4. Not 5 because common variations users say are missing ("bun install", "bun test", "npm", "JavaScript/TypeScript", ".lockfile").

Distinctiveness Conflict Risk

The named tool "Bun" gives a clear niche with distinct triggers, matching anchor 4's "mostly distinct; minor overlap risk with closely related skills" — generic phrases like "runtime, package manager, bundler, and test runner" could overlap with Node/npm/Vercel skills. Not 5 because those generic role words carry more conflict risk than anchor 5's fully concrete triggers.