Conciseness

The "Reasoning Strategy" paragraph explains immunology Claude already knows ("MHC-I for CD8+ CTL response, MHC-II for CD4+ helper response", surface-exposed targets are better antibody sites), and the "MHC binding does not equal immunogenicity" caveat is repeated three times across the body. This matches "mostly efficient but includes some unnecessary explanation"; it is not 4 because an entire multi-sentence paragraph plus repetition could be trimmed without losing tool-irreplaceable information.

Actionability

Mostly executable guidance: the IEDB call uses real parameters (taxon ID "eq.NCBITaxon:2697049", method "netmhcpan_el", allele "HLA-A*02:01") and the bundled `scripts/population_coverage.py` commands with expected output are copy-paste ready. It is not 5 because several examples are placeholder templates ("[organism]", "[antigen_aa_sequence]", "[variant_in_epitope]") and Phase 4's EnsemblVEP/PubMed guidance is thin relative to the concrete standard set elsewhere.

Workflow Clarity

Clear Phase 0–5 sequence with decision thresholds at each phase (percentile-rank cutoffs, coverage-target table with corrective actions like "Add more epitopes", conservation tiers with "avoid"/"redesign" guidance). It is not 5 because there are no explicit output-validation steps (e.g., verifying returned epitope data or re-running after a failed/empty prediction) — checkpoints are decision rules rather than validation-with-feedback loops.

Progressive Disclosure

The single bundle file (`scripts/population_coverage.py`) is real, clearly signaled in the body, one level deep, and its bundled-default caveat is well explained — good structure overall. It is not 5 because the ~230-line body inlines reference-style material (the 14-tool table, HLA supertype frequency lists, multiple threshold tables) that could be split into a references file, leaving SKILL.md as a leaner overview.

Specificity

Lists multiple concrete actions — "MHC-I/MHC-II epitope prediction (IEDB)", "population HLA coverage optimization", "B-cell epitope identification", "cross-strain conservation analysis", "multi-epitope construct design" — covering the full pipeline. It is not the level-4 anchor because there are no minor gaps: each pipeline stage is named as a specific action.

Completeness

Explicitly answers both: the first sentence states what it does (full enumerated pipeline) and the "Use for..." clause gives four concrete when-triggers. This matches the level-5 anchor with both what and when clearly and explicitly stated; it is not 4 because the when-clause is already specific and trigger-phrase-based rather than improvable.

Trigger Term Quality

"Use for vaccine epitope prediction, HLA allele coverage, multi-epitope construct design" gives good natural-phrase coverage a user would plausibly say. It falls short of 5 because common synonyms like "T-cell epitope", "peptide vaccine", "antigen design", or "population coverage" as a standalone phrase are missing.

Distinctiveness Conflict Risk

"Computational vaccine candidate design" via "epitope prediction" and "HLA coverage" is a clear niche with distinct, domain-specific triggers — minimal overlap risk with generic bioinformatics skills. It is not 4 because the vocabulary (MHC-I/MHC-II, B-cell epitope, multi-epitope construct) is specific enough that wrong-skill triggering is unlikely.