Conciseness

The body is dense and project-specific with no general-concept padding (tables compress the mental model, worlds, and boundary decisions effectively). Not 5: the Scope section largely repeats the frontmatter description, the Review Checklist recaps rules already stated in body sections, and the module-ownership rule appears in multiple sections — minor instances of redundancy that could be trimmed.

Actionability

For an instruction-only skill the guidance is fully actionable: exact file paths (crates/biome_js_type_info/src/type_data.rs, .../requests/), concrete API names to use or avoid ('Declare domains: &[RuleDomain::Types]', 'Typed<N>', 'TypeInferenceRequestContext', 'infer_module_types_bottom_up'), numbered step sequences for both common workflows, and copy-paste-ready decision orders. Not 4: no gaps in concrete guidance for the covered cases.

Workflow Clarity

Multi-step processes are clearly sequenced (5-step workflows for type-aware rules and raw inference changes), the boundary decision order is explicit, and validation is present via per-boundary testing guidance and a closing Review Checklist. Not 5: there are no explicit validate-then-fix-then-retry feedback loops for error recovery, only implied checkpoints.

Progressive Disclosure

The body is a clear overview that delegates detail to well-signaled, one-level-deep references: a task-to-guide table linking the two CONTRIBUTING.md guides, and named-section pointers ('Request architecture', 'Adding a tracked query', 'Resolver helpers') plus a cross-reference to load 'testing-codegen' for snapshot mechanics. No bundle files exist to reference, and the split between inline overview and external guides is appropriate for this codebase skill.

Specificity

The description lists multiple specific concrete capabilities — 'type-aware lint rules, raw collection or inferred representations, analyzer requests, tracked queries, import or cycle resolution, profiling, and Salsa invalidation tests' — giving comprehensive coverage of the skill's niche. Not 4: there are no minor gaps; the capability list is exhaustive for this domain.

Completeness

It explicitly answers both what (the enumerated capability list) and when ('Use this skill when working on Biome's Salsa-backed JavaScript and TypeScript inference'), with concrete trigger phrases plus explicit 'Do not use for...' exclusions. Not 4: the when-clause is already explicit and specific, not merely present-but-imprecise.

Trigger Term Quality

Good keyword coverage with phrases a Biome contributor would naturally say ('JavaScript and TypeScript inference', 'type-aware lint rules', 'tracked queries', 'profiling', 'invalidation tests'), and JS/TS synonyms appear. Not 5: phrasings like 'raw collection or inferred representations' lean toward internal jargon, and a few natural variations (e.g., 'infer types', 'type checking') are absent.

Distinctiveness Conflict Risk

The niche is unambiguous (Biome's Salsa-backed JS/TS inference) and the explicit negative triggers — 'standalone CSS/HTML module-graph data unrelated to JS/TS inference or for ordinary semantic binding analysis' — sharply reduce overlap with sibling skills. Minimal conflict risk.