The body is dense and high-signal — e.g., 'Treat `any` as a code smell; use `unknown` for truly unknown values' and 'Do not use `enum` for string constants' — with no padding explaining what TypeScript is or how basic concepts work. Every token earns its place, matching the lean/efficient anchor and not the 'mostly efficient but could be tightened' level.

Provides concrete, executable snippets — 'function merge<T extends object, U extends object>(a: T, b: U): T & U', mapped/conditional types, type guards, branded types, and 'assertNever' — that are copy-paste ready. It is not level 2 because the code is real and complete rather than pseudocode or missing key details.

This is a single-purpose reference skill with no multi-step or destructive workflow, and the material is clearly organized into Key Principles, Techniques, Common Patterns, and Pitfalls. Per the simple-skills note, workflow clarity can score 3 when the content is clear and well-organized.

The skill is under 50 lines with no external references and no bundle files, and content is organized into clear, well-signaled sections. Per the guideline, progressive disclosure can score 3 for short skills needing no external references when sections are well-organized.

Names the domain (TypeScript) and lists multiple concrete capability areas — 'type system, generics, utility types, and strict mode patterns' — rather than vague abstractions. It is above level 2 because the coverage spans four distinct, specific topics rather than just naming the domain.

It answers 'what does this do' (expert for type system, generics, utility types, strict mode) but has no 'Use when...' clause or equivalent explicit trigger guidance, which per the guidelines caps completeness at 2. It is not level 3 because the 'when' is entirely missing.

Relevant keywords like 'TypeScript', 'generics', and 'strict mode' appear, but the phrasing leans technical and misses common natural variations a user might say ('type errors', 'type safety', 'fixing types', 'tsconfig'). It is not level 3 because keyword coverage is not broad enough for natural user phrasing, and not level 1 because clearly relevant terms are present.

The focus on type-system specifics (generics, utility types, strict mode) carves a niche, but the generic 'TypeScript expert' framing with no narrowing trigger could still overlap with general TS or coding skills. It is not level 3 because the broad 'expert' framing lacks distinct triggers, and not level 1 because it is clearly domain-specific rather than generic.