Conciseness

The body is ~1,780 lines / ~45KB with every one of nine sections opening with a padded 'The Problem with X' preamble that explains concepts Claude already knows (why try-catch is hard to reason about, why callback hell is bad). There is also real duplication: the async fetch-to-TaskEither wrapping in section 1 reappears nearly verbatim in section 6, and the tryCatchSync/tryCatchAsync helpers overlap with section 8's bridge functions. This matches 'noticeably verbose; several unnecessary explanations or padded sections' rather than anchor 3, where the excess would be minor.

Actionability

Nearly all guidance is concrete, executable TypeScript with imports, presented as before/after pairs plus numbered step-by-step refactoring guides ('Identify the error type... Replace throw statements with E.left(...)') and a mapping table of imperative constructs to fp-ts equivalents. Minor gaps keep it from anchor 5: a few snippets reference undefined identifiers (postgresClient, smtpClient) or unimported modules (O in the unfold example), and some helpers are stubbed with '/* ... */'.

Workflow Clarity

Sequence exists (per-pattern step-by-step guides, module-by-module migration strategy, type-driven development workflow), but validation checkpoints are only implicit: 'Test thoroughly before moving on' names testing without any concrete verification step such as running tsc or the test suite after each conversion. This fits 'steps listed but validation gaps; checkpoints missing or implicit' — above anchor 2 because real sequences with concrete sub-steps are present.

Progressive Disclosure

The file is well structured internally (table of contents, nine numbered sections, quick-reference table), but there are no bundle files at all: a 1,780-line cookbook of patterns, pitfalls, and adoption strategies is inlined entirely in SKILL.md when the pattern library, pitfalls, and adoption guides clearly belong in separate reference files. This matches 'some structure but could be better organized; content that should be separate is inline' — above anchor 2 because section headers and a TOC provide real navigation.

Specificity

The description names its domain ('refactoring imperative TypeScript code to fp-ts functional patterns') and one concrete action, but does not enumerate the actual conversions it covers (try-catch to Either, null checks to Option, Promise chains to TaskEither, class DI to Reader). This matches 'names domain and 1-2 concrete actions, but not comprehensive'; it is above anchor 2 because the domain and action are real and specific, not generic.

Completeness

The 'what' is clear (refactor imperative TypeScript to fp-ts patterns), but there is no 'Use when...' clause or equivalent explicit trigger guidance anywhere in the description, which per the rubric caps completeness at 3. It is not anchor 2 because the 'what' is concrete rather than vague.

Trigger Term Quality

Relevant natural keywords are present ('refactoring', 'TypeScript', 'fp-ts', 'functional patterns'), but common variations a user would actually say are missing: 'migrate/migration', 'error handling', 'Either', 'Option', 'TaskEither'. This sits at 'some relevant keywords but missing common variations or synonyms' rather than anchor 4, whose example shows a broader set of natural trigger terms.

Distinctiveness Conflict Risk

'fp-ts functional patterns' names a specific library and a specific niche (imperative-to-functional TypeScript migration), giving it distinct triggers and minimal overlap risk with other skills. Unlike anchor 4's 'minor overlap risk with closely related skills', the library name pins the domain unambiguously.