Conciseness

The body is lean (~250 words) with no padding, but the DRY paragraph ("Three similar statements still beat a premature abstraction. Prefer explicit over clever. Test behavior and edge cases, not line counts.") restates programming wisdom Claude already knows, matching anchor 4 for minor instances of over-explanation rather than 5.

Actionability

Concrete, executable heuristics are given ("Define core types early, trace every access pattern", "ask 'what happens if another actor modifies this concurrently?' If not 'nothing', isolate", "does every subsequent phase benefit from this existing?"); as an instruction-only skill the absence of code is not penalized, but no worked examples are provided, matching anchor 4 rather than 5.

Workflow Clarity

The decision sequence is explicit and coherent ("Subtraction comes before scaffolding", "setup before features, tests before fixes", data structures before logic); there are no destructive or batch operations so no validation cap applies, but there is no explicit tie-breaking guidance when principles conflict, matching anchor 4.

Progressive Disclosure

The body is ~20 lines, well under 50, with no need for external references (none are referenced and no bundle files exist); the bolded lead-ins (**Data structures first.**, **Concurrency corollary.**, **Scaffold first.**) delineate clear sections, so per the short-skill guideline it qualifies for the full score.

Specificity

"choosing core types and data structures, sequencing scaffold-vs-feature work, asking what concurrent actors share" lists three specific actions within the design domain, matching the anchor for several specific actions with minor gaps in coverage; it falls short of 5 because coverage is not comprehensive and the phrasing stays somewhat abstract.

Completeness

Both what ("Get the data structures right so downstream code becomes obvious") and when ("Apply before writing logic" plus three trigger situations) are present, so the missing-'Use when' cap at 3 does not apply since equivalent explicit trigger guidance exists; the when could be more explicit and use more concrete trigger phrases, matching anchor 4 rather than 5.

Trigger Term Quality

Relevant keywords exist ("core types", "data structures", "scaffold", "concurrent") but the phrasing is jargon-leaning ("scaffold-vs-feature work", "concurrent actors") and misses natural variations users would actually say ("data model", "schema design", "when to abstract"), matching the anchor for some relevant keywords missing common synonyms; not 4 because keyword coverage is not broad enough.

Distinctiveness Conflict Risk

The foundational-design niche (data-shape-first, scaffold sequencing, concurrency isolation) is clearly distinguishable from most skills with only minor overlap risk against general refactoring or architecture-principle skills, matching anchor 4; not 5 because the domain still broadly applies to all coding work.