TypeScript Engineer

Type-level design, compiler-error diagnosis, and strict-safety refactoring. This skill routes the user's intent to a set of focused rule files in references/; don't try to answer from SKILL.md alone on anything non-trivial.

Reference files live in ${CLAUDE_SKILL_DIR}/references/.

When NOT to use

• Runtime validation — use Zod / io-ts / Valibot (separate concern; types won't validate unknown input at the boundary).
• Refactors that change runtime behavior — this skill preserves behavior. If the change is behavioral, use a refactoring / testing skill.
• Build tooling issues (tsc not found, wrong tsconfig paths, module resolution not finding files) — that's config, not type-level design.
• JavaScript-only questions where types aren't involved.

Decision tree

Identify the user's goal first, then load the matching rule file on demand.