Conciseness

The tool documentation, JSON examples, and code tables are tight and factual, but the 'Reasoning Framework for Result Interpretation' section spends ~30 lines explaining textbook population genetics Claude already knows ('Fst measures population differentiation (0 = no differentiation, 1 = complete fixation...)', 'Uncontrolled population structure in GWAS inflates false positives', 'AFR populations have shorter LD blocks'). This matches 'Mostly efficient but includes some unnecessary explanation or could be tightened'; it is not 4 because the padded conceptual explanation is a full section, not a minor instance, and not 2 because the bulk of the body is dense, non-padded reference material.

Actionability

Every tool gets exact parameter signatures, return shapes, and copy-paste-ready JSON call examples ('{"superpopulation": "AFR", "limit": 10}', '{"gene_symbol": "TCF7L2", "limit": 10}'), plus response examples and a worked workflow. This matches 'Fully executable; copy-paste ready code or commands; specific examples cover the common cases'; it is not 4 because there are no missing key details in the tool call guidance.

Workflow Clarity

The 'Workflow: Population Stratification in GWAS' section lays out a clear Steps 1-4 sequence, and the NOTE 'population takes a population code (e.g. "YRI"), not a superpopulation code' acts as an explicit error guard. It fits 'Clear sequence with most checkpoints present; minor validation gaps' — the workflow is read-only analysis so heavy validation loops are less critical, but Step 4 ('Cross-reference with population data for stratification analysis') is underspecified with no concrete method. Not 5 because there are no explicit validation/synthesis checkpoints inside the workflow itself, and not 3 because the sequence is concrete and guarded rather than leaving checkpoints merely implicit.

Progressive Disclosure

No bundle files exist (no references/, scripts/, assets/), so the skill is a single file; it is well-sectioned with clear headers (When to Use, NOT for, Phases 1-4, Workflow, code tables, quick reference) and easy to navigate. This matches 'Good structure; most content is appropriately placed; minor organization gaps': the reasoning framework and code tables are arguably reference-file material inlined in SKILL.md, and the trailing 'Tool Parameter Quick Reference' partially duplicates the phase sections. Not 5 because nothing is split out into clearly-signaled one-level-deep reference files; not 3 because organization is strong, references are not buried, and no content is misfiled.

Specificity

The description lists multiple concrete actions — 'superpopulation/population search, sample metadata, variant frequencies across AFR/AMR/EAS/EUR/SAS, ancestry-specific analyses' — with comprehensive, domain-specific coverage and no vague filler. This matches the anchor 'Lists multiple specific concrete actions; comprehensive coverage'; it is not the level below because coverage of the skill's capabilities is broad rather than leaving 'minor gaps'.

Completeness

Both questions are explicitly answered: the 'what' is stated concretely (population/sample search, sample metadata, variant frequencies, ancestry-specific analyses) and the 'when' is an explicit 'Use for ancestry comparison, population-aware allele frequency lookups, and 1000-Genomes-cohort-specific analyses' clause with concrete trigger phrases. This matches the top anchor; it is not the level below because the 'when' is explicit and specific rather than merely present.

Trigger Term Quality

Natural terms users would say are well covered: '1000 Genomes', 'IGSR', 'population', 'superpopulation', 'ancestry comparison', 'population-aware allele frequency lookups', 'population genetics'. A few natural terms are missing — notably GWAS-related and population-stratification phrasing, even though the body devotes Phase 4 and a workflow to GWAS population stratification, so users asking those questions would not trigger on this description. This fits 'Good keyword coverage; a few natural terms missing' rather than the comprehensive-with-synonyms anchor.

Distinctiveness Conflict Risk

The description carves a clear niche (1000 Genomes / IGSR cohort) and actively de-conflicts with the nearest neighbor: 'distinct from gnomAD which has different sample composition'. Trigger terms (IGSR, 1000 Genomes, superpopulation codes) are unlikely to fire for other skills, matching the 'Clear niche with distinct triggers; minimal conflict risk' anchor.