Conciseness

The body is dense, imperative, and free of explanations of concepts Claude already knows, with every step carrying API-specific constraints (option names, error codes, lifecycle rules). It sits at anchor 4 rather than 5 because of some cross-section repetition: secure-context and permissions-policy checks appear in Step 2.5, Step 5.2, and the Error Handling section, and the worker/server mismatch is stated in both Step 2.7 and the final error bullet.

Actionability

Guidance is fully concrete throughout: the executable command "node scripts/find-proofreader-targets.mjs .", exact bundle paths to read and adapt (references/*.md, assets/proofreader-session.template.ts), specific API surface names (availability(), create(), proofread(), measureInputUsage(), destroy()), exact option names, and named exception types (NotAllowedError, NotSupportedError, OperationError). This matches the anchor for executable, case-covering guidance; per the rubric's scoring note, absence of inline code in an instruction-only skill is not penalized when the guidance is this actionable and the details are delegated to real reference files.

Workflow Clarity

Five clearly sequenced procedure steps culminate in a dedicated validation step (re-run the inventory script, verify feature detection and policy access, test with the exact production options, run build/typecheck/tests), and the Error Handling section provides per-error remediation with an explicit retry-once feedback loop. This matches the anchor for explicit validation steps with feedback loops for error recovery.

Progressive Disclosure

SKILL.md stays a procedural overview while all detail is split one level deep into four references, one script, and one template asset, each existing on disk and each gated by a clear "Read X when Y" signal (e.g., "Read references/compatibility.md when preview flags... matter"). No nested references were found in the bundle files, matching the anchor for a clear overview with well-signaled one-level-deep references.

Specificity

"Implements and debugs browser Proofreader API integrations in JavaScript or TypeScript web apps" names two concrete top-level actions, and the Use-when clause enumerates five specific tasks ("availability checks, monitored model downloads, proofread flows, correction metadata handling, or permissions-policy checks"), matching the anchor for multiple specific concrete actions with comprehensive coverage. It is not a 4 because the action coverage spans the API's full task surface without generic filler.

Completeness

The description explicitly answers both what ("Implements and debugs browser Proofreader API integrations in JavaScript or TypeScript web apps") and when ("Use when adding Proofreader availability checks, monitored model downloads, proofread flows...") with concrete trigger phrases, plus negative scope guidance. This matches the anchor-5 example structure exactly.

Trigger Term Quality

Natural domain terms users of this API would say are present ("proofread", "proofreading", "correction", "model downloads", "permissions-policy"), giving good keyword coverage. It falls short of anchor 5 because common user synonyms like "spell check", "grammar check", or "text correction" are missing.

Distinctiveness Conflict Risk

It carves out a clear niche (built-in browser Proofreader API) with distinct triggers and explicitly excludes adjacent domains that would otherwise collide ("generic prompt engineering, server-side LLM SDKs, or cloud AI services"), minimizing conflict risk. Not a 4 because the exclusions remove even the minor overlap with general LLM-assistant skills.