Conciseness

The ~37-line body is lean and assumes Claude's competence: rules like "The script accepts max_items; single gene entry lookups usually do not need it, while search and download endpoints are better with max_items=10" and "Treat displayed `...` in tool previews as UI truncation" add non-obvious operational facts with no padding or concept explanation. It is not 4 because no section can be trimmed without losing real information.

Actionability

Fully executable guidance: a copy-paste bash invocation ("echo '{...}' | python scripts/rest_request.py"), three complete request JSON examples covering the common endpoint patterns, an explicit field list for Input, and the documented fields (max_items, save_raw, response_format, record_path, etc.) all verified to exist in scripts/rest_request.py. It is not 4 because the examples cover the common cases with no gaps.

Workflow Clarity

This is a simple single-task skill (make compact HPA requests) under 50 lines, and the single action is unambiguous: the "Prefer these paths" line maps each intent to a concrete endpoint and the Output section defines both success (ok, records/summary/text_head) and failure (ok=false with error.code/error.message) handling, giving an explicit error-recovery signal. Operations are read-only HTTP lookups, so no destructive/batch validation cap applies.

Progressive Disclosure

The skill is under 50 lines with no need for external references, and the body is well organized into Operating rules, Execution behavior, Input, Output, Execution, and References sections. The single bundle file (scripts/rest_request.py) is real and clearly referenced, and the References section explicitly states no additional references are required — nothing is inlined that belongs in a separate file.

Specificity

The description lists multiple concrete actions — "Submit compact Human Protein Atlas requests for gene JSON, search downloads, and page-level tissue or cell-line lookups" plus "save raw JSON or HTML only on request" — covering all of the endpoint families the body documents, in third person. It is not a 4 because there is no minor coverage gap: the gene-entry, search-download, and page-level lookup actions map one-to-one onto the skill's documented paths.

Completeness

Both "what" (submit compact HPA requests for three lookup types) and "when" ("Use when a user wants concise Human Protein Atlas summaries; save raw JSON or HTML only on request") are explicit. It falls short of 5 because the trigger clause covers only the summary use case; users asking for tissue/cell-line expression lookups or raw JSON/HTML dumps are only weakly implied by the when-clause.

Trigger Term Quality

Good natural keyword coverage — "Human Protein Atlas", "gene JSON", "search downloads", "tissue", "cell-line", "summaries" — but common user variations like the "HPA" abbreviation, "protein expression", or "ENSG"/Ensembl IDs are absent. It is not 3 (keywords are strong and domain-specific, not generic) and not 5 (synonym coverage is incomplete).

Distinctiveness Conflict Risk

"Human Protein Atlas" names a clear, narrow niche with distinct triggers; no plausible conflict with other skills. It is not 4 because even minor overlap risk is absent — the domain name itself is the discriminator.