Conciseness

Sections are directive with dense tables and short, purposeful code blocks — genuinely efficient overall. However, the "Quick Reference: Common Mistakes" table restates rules already covered in the preceding sections, and asides like the "**Why:** as const is erased... bundler can tree-shake" explanation restate TypeScript knowledge Claude already has. Anchor 4 (minor trimmable instances) fits better than anchor 5 (every token earns its place) and better than anchor 3 (only minor tightening needed, not pervasive).

Actionability

Concrete, executable TypeScript throughout: bad/good code pairs (the `any` vs `unknown` narrowing example), a naming table with real identifiers, real tsconfig/import rules ("import { helper } from \"./utils.js\" // Correct"), and a full discriminated-union pattern. Code is copy-paste ready and covers the common cases, matching anchor 5.

Workflow Clarity

This is a conventions skill, and its per-topic rules are unambiguous (e.g., "Variables — only when the type cannot be inferred", "Always enable `strict: true`"). But there is no verification checkpoint (e.g., running `tsc --noEmit` to confirm compliance), and the simple-skill exception for scoring 5 applies to sub-50-line single-task bodies, which this ~230-line multi-topic body is not. Anchor 4 (clear, minor validation gap) fits better than 3, whose 'sequence present but checkpoints missing' implies vague or implicit steps.

Progressive Disclosure

The body is an overview of core conventions with depth correctly pushed to four real, one-level-deep reference files. "Additional Resources" summarizes what each file owns ("Each topic lives in exactly one file — open the one that owns it"), and in-text pointers are section-specific ("references/patterns.md (Assertion Functions)", "references/project-structure.md (Import Organization)"). All cited paths exist in the bundle. This matches anchor 5: clear overview, well-signaled shallow references, easy navigation.

Specificity

The description enumerates concrete capability areas — "strict mode, naming, type annotations, the type system (generics, utility types, conditional and mapped types), discriminated unions, error handling, async patterns, immutability, and project structure" — comprehensively covering the skill's scope. It fits the anchor-5 example (multiple specific items, comprehensive coverage) rather than anchor 4, which reserves room for coverage gaps that are not present here.

Completeness

It explicitly answers both what (the enumerated convention topics) and when (quoted trigger phrases plus a general condition), matching the anchor-5 pattern of the good example. Anchor 4 would require the 'when' to be less explicit, but the quoted trigger list is maximally concrete.

Trigger Term Quality

It quotes natural user utterances — "write TypeScript code", "create a TypeScript module", "define TypeScript types", "add type annotations", "use generics", "handle errors in TypeScript", "set up tsconfig", "organize a TypeScript project" — plus a broad catch-all ("whenever writing any TypeScript that is not tied to a specific library or framework"). This is comprehensive natural-term coverage with variations, matching anchor 5; anchor 4 would apply only if common phrasings were missing, and none are.

Distinctiveness Conflict Risk

"library-agnostic" plus explicit negative scope naming sibling skills — React/UI frameworks ("react-best-practices, react-feature-sliced-design"), CLI packaging ("npx-package"), plain JavaScript, and service APIs ("aws-dynamodb-best-practices") — carves a clear niche. Minimal conflict risk, matching anchor 5; anchor 4's 'minor overlap risk with closely related skills' is undercut by the explicit exclusion list.