Conciseness

The bulk is high-value operational content Claude cannot know (exact tool inputs/outputs, parameter gotchas like "NOT query" and the literal "HLA-I" string, IC50 thresholds, allele-availability warnings). Minor over-explanation remains: the Reasoning Strategy paragraph re-explains HLA biology, and the abacavir/HLA-B*57:01 hypersensitivity example appears twice (Reasoning Strategy and Phase 5).

Actionability

Every tool is documented with name, inputs, and outputs, tricky parameters are explicitly called out, and the verified live examples (e.g., `IPD_search_hla_alleles({"name": "A*02:01"})`, `MHCMotifAtlas_get_allele_ligands({"allele": "A0201"})`) are copy-paste-ready calls covering the common cases. The "COMPUTE, DON'T DESCRIBE" directive reinforces executable analysis, and the absence of Python code is appropriate for an instruction-only tool-orchestration skill.

Workflow Clarity

Phases 0-6 are clearly sequenced with per-phase objectives and workflows, and the Edge Cases & Fallbacks section provides error-recovery loops ("If allele not found: Check nomenclature...", "BVBRC empty results: Try broader organism name"). It stops short of 5 because there are no explicit validation checkpoints between phases (only the implicit "confirm species early" guideline).

Progressive Disclosure

The single-file body is well-sectioned (database table, phase diagram, per-phase details, edge cases, limitations) with no nested references and no bundle files to mis-navigate. However, at 258 lines it far exceeds the simple-skill case, and roughly 150 lines of per-database tool API detail (Phase tool listings, IPD/ligand-atlas parameter specifics) are inlined where a references/TOOL_API.md file could offload them from the always-loaded context.

Specificity

The description lists several concrete actions ("HLA gene-family analysis", "MHC-peptide binding") across three application contexts ("transplant compatibility, vaccine epitope coverage, and cancer immunotherapy") and names four specific databases (IMGT, IEDB, UniProt, DGIdb). It falls short of 5 only because it omits some capabilities the skill actually performs, such as naturally-presented ligand retrieval and protein annotation lookup.

Completeness

It clearly answers both questions: the "what" ("HLA gene-family analysis and MHC-peptide binding... Uses IMGT... IEDB... UniProt... DGIdb") and an explicit "when" with concrete trigger phrases ("Use for HLA typing/imputation review, vaccine HLA coverage, and immunotherapy prediction biomarkers"). This matches the anchor for both what AND when with concrete triggers.

Trigger Term Quality

Good coverage of natural domain phrases users would actually say: "HLA typing", "vaccine HLA coverage", "neoantigen presentation", "HLA-LOH", "epitope". A few common variations are missing ("MHC restriction", "antigen presentation", "T-cell epitope"), keeping it below the comprehensive-synonym level of 5.

Distinctiveness Conflict Risk

The HLA/immunogenomics niche is distinct with domain-specific triggers, but the phrase "immunotherapy prediction biomarkers (HLA-LOH, neoantigen presentation)" creates minor overlap risk with a sibling neoantigen/immunotherapy-prediction skill. Not 5 because that overlap is not disambiguated within the description itself; not 3 because the core HLA-binding triggers are unmistakably specific to this skill.