Conciseness

The body is overwhelmingly tool-specific knowledge Claude would not have — exact parameter names, gotchas ("`alphafold_get_prediction/summary` | `uniprot_id` | `qualifier`"), and verified live examples — with cross-references used in places ("see gotcha below", "see Workflow 5b below"). It is not a 5 because of genuine redundancy: "(verified live)" appears roughly twenty times and the `PDBe_get_compound_structures` gotcha is fully restated in three places (Workflow 2, the gotcha table, and Limitations). It is not a 3 because there is no padding and no explanation of concepts Claude already knows.

Actionability

Mostly executable guidance: exact tool names with parameter signatures, a mistake-vs-correct gotcha table, and literal verified invocations like "`CATH_get_domain_summary(domain_id="1cukA01")`" and "`InterPro_get_member_signature(member_database="pfam", accession="PF00069")`". It falls short of the 5 anchor because several workflow phases are high-level labels without concrete calls (e.g. Workflow 3's "Phase 5: AlphaFold + Foldseek structural comparison", Workflow 1's bare phase arrows), leaving minor gaps.

Workflow Clarity

Workflows have clear phased sequences with explicit decision criteria ("Resolution <2.5A for drug design. X-ray > Cryo-EM > NMR > AlphaFold... Holo > apo") and validation/trust gates plus feedback loops ("retry 1-2 times before reporting an entry is missing", PDBeValidation quality gating, BMRB validation before trusting shifts). It misses the 5 anchor because the workflows are presented out of order in the document (1, 4, 5, 5b, 6, 7, 8, then 2, 9, 3), which breaks the coherence of the overall process.

Progressive Disclosure

Section headers are clear and navigation within the file is decent, but the entire skill is a single ~310-line file: the ~80-line tool inventory and the per-database workflow details (Workflows 4-9) are content that clearly belongs in separate reference files, and no references/ bundle exists. This matches the 3 anchor (structure present but content that should be separate is inline) rather than the 2 anchor, which requires minimal structure.

Specificity

The description enumerates many concrete capabilities and data sources — "Combines PDB experimental structures, AlphaFold predictions, GPCRdb, SAbDab antibody structures, ProteinsPlus binding-site prediction, BindingDB ligand-affinity data, BMRB NMR data..." plus specific actions like "druggability assessment, binding-site characterization, ligand-pocket analysis, structural-confidence scoring (resolution, pLDDT)". Coverage is comprehensive rather than having minor gaps, so it matches the 5 anchor rather than 4.

Completeness

Both questions are answered explicitly: the "what" ("Combines PDB experimental structures, AlphaFold predictions, GPCRdb, SAbDab antibody structures...") and the "when" ("Use for druggability assessment, binding-site characterization, ligand-pocket analysis, structural-confidence scoring (resolution, pLDDT), antibody-target interface analysis..."). This matches the 5 anchor with concrete trigger phrases, not the 4 anchor where 'when' is weaker.

Trigger Term Quality

Natural domain phrases a user would actually say are comprehensively present: "drug target validation", "druggability", "binding site", "AlphaFold", "antibody", "membrane-protein topology", "disordered region", "MD simulations", "NMR", plus tool-name synonyms. No common variations obviously missing for this domain, fitting the comprehensive-synonyms 5 anchor rather than the 4 anchor.

Distinctiveness Conflict Risk

The niche — structural-biology/proteomics integration specifically for drug target validation across named databases — is clear and distinct, but the very broad database sweep (PDB, AlphaFold, BindingDB, MD metadata, NMR) creates minor overlap risk with single-domain structural-bioinformatics skills. This fits the 4 anchor (mostly distinct, minor overlap risk with closely related skills) better than the 5 anchor's minimal-conflict bar.