Conciseness

The body opens with a tight one-liner ("TaskEither = async operation that can fail. Like Promise<Either<E, A>>.") and uses compact code with inline comments, with every section earning its place and no padding of concepts Claude already knows.

Actionability

Fully executable TypeScript with real imports covers the common cases — create (right/left/tryCatch), transform (map/flatMap/orElse), execute, parallel sequenceT, and recovery — making it copy-paste ready.

Workflow Clarity

As a simple single-purpose reference it is organized into an unambiguous Create → Transform → Execute progression with a Common Patterns section, satisfying the simple-skill exception for workflow clarity.

Progressive Disclosure

Clear section headers give good navigation and all content legitimately belongs inline for a reference card, but at roughly 95 lines it exceeds the under-50-line threshold under which well-organized sections alone would warrant a 5, and there are no external references to signal.

Specificity

Names the domain clearly ("Quick reference for TaskEither") and lists use scenarios, but the only stated action is the generic "quick reference" rather than concrete operations like create, transform, or chain.

Completeness

Both halves are present — a clear "what" (quick reference for TaskEither) and an explicit "Use when…" trigger clause — but the "what" does not enumerate the specific actions the reference covers, keeping it just below a 5.

Trigger Term Quality

Natural phrases a user would say ("async error handling", "API calls", "Promise-based operations that can fail") give good coverage, though common synonyms like fetch, try/catch, or .catch are missing.

Distinctiveness Conflict Risk

Leading with the named TaskEither construct carves a clear niche, but the broad triggers "async error handling" and "API calls" could overlap with general error-handling or fetch-helper skills.