Conciseness

The body opens with a 12-character definition ("Option = value that might not exist") and every section is bare API lines with terse inline comments; there is no padding, no explaining of concepts Claude already knows. This matches anchor 5 ('lean and efficient; every token earns its place'); even the Nullable comparison adds comparative value in two lines.

Actionability

Create and Common Patterns sections are executable with imports included and copy-paste-ready pipelines, but the Transform/Extract sections are signature placeholders ("O.map(fn)", "O.getOrElse(() => default)") rather than runnable code. This is mostly executable with minor gaps — anchor 4 — rather than anchor 5's fully copy-paste-ready bar across all sections.

Workflow Clarity

This is a simple single-purpose reference skill with no multi-step process; the simple-skill exception applies and the single action (look up the Option API) is unambiguous, organized by Create/Transform/Extract/Patterns. No destructive or batch operations exist, so no validation checkpoints are required for a score of 5.

Progressive Disclosure

The skill is a short (~72-line) self-contained quick reference with no bundle files; all content genuinely belongs inline and splitting it into references would be over-engineering. Sections are well-organized and navigable, satisfying the simple-skill exception for progressive disclosure (well-organized sections, no external references needed).

Specificity

"Quick reference for Option type" names the domain and "handle nullable values, optional data, or wants to avoid null checks" gestures at 1-2 actions, but no concrete API operations (create, map, chain, extract) are listed. It sits above anchor 2 (bare domain naming like 'Processes PDF files') because handling nullables/optional data adds substance, but below anchor 4 which expects several specific listed actions.

Completeness

Both what ("Quick reference for Option type") and when ("Use when user needs to handle nullable values, optional data, or wants to avoid null checks") are explicit, with concrete trigger phrases in the when-clause. This matches the anchor 5 pattern of explicitly answering both what and when with concrete triggers; anchor 4's example has a weaker 'when' than this description.

Trigger Term Quality

Natural phrases users would say are present: "nullable values", "optional data", "avoid null checks". Missing common synonyms and ecosystem terms like 'Maybe', 'fp-ts', 'Option monad', or '.map' chaining language. Good coverage but not comprehensive per the anchor 5 bar (which expects synonyms and extensions), matching anchor 4's 'a few natural terms missing'.

Distinctiveness Conflict Risk

"Option type" without naming fp-ts/TypeScript is ambiguous — Rust's Option, Swift's Optional, and generic null-handling advice could all plausibly trigger this skill. It is more specific than 'helps with document files' (anchor 2) but carries real overlap risk with closely related nullable-handling skills, fitting anchor 3.