Conciseness

Dense, terse, and almost entirely repo-specific knowledge (type tables, operator grammar, security caps) with no generic Go/HTTP tutorials. It is not a 5 because several topics are repeated across sections — range-splitting appears in 'Multi-filter semantics', Step 4, and the 'Range queries' gotcha; validation ownership is stated three times; dot-notation in three places — which could be consolidated; not a 3 because the length reflects genuine reference material rather than padding.

Actionability

Copy-paste-ready Go snippets with real imports, exact file paths with line numbers (e.g. "api/v3/filters/parse.go:16-19", "openmeter/customer/customer.go:296"), concrete commands ("make gen-api", "httptest.NewRequest"), and representative error-message strings. Coverage spans handler, service, adapter, and test layers.

Workflow Clarity

Six clearly ordered steps, each naming its target files, with mandatory validation checkpoints ("ALWAYS add service level tests") that enumerate the exact test cases to cover (shorthand, eq, contains, oeq, range, unknown-field 400, mutually-exclusive 400, dot-notation) and an Error Handling section that maps error messages to causes. A 4 would require missing or merely implicit checkpoints; the only blemish is cosmetic (Step 6 says 'three additional layers' then lists four).

Progressive Disclosure

Sections are well-organized with clear headers, and references to repo source files are clearly signaled with path:line citations, but no bundle files exist and roughly 150 lines of stable reference material (filter grammar, type-mapping tables, error-message catalog) are inlined in SKILL.md where the rubric expects them to live one level deep in a references/ file. Not a 4 because the bulk reference content is inline rather than split out; not a 2 because structure and signaling are good, not buried.

Specificity

"Add, modify, or convert AIP-style query-parameter filters on v3 list endpoints" plus enumerated sub-tasks ("wiring filter parsing into a handler", "converting API filters into pkg/filter predicates", "debugging filter parsing/validation behavior") lists multiple concrete actions with comprehensive coverage of the domain. It is not a 4 because no meaningful capability is left out of the action list.

Completeness

Explicitly answers both what ("Add, modify, or convert AIP-style query-parameter filters on v3 list endpoints") and when ("Use when adding filterable fields to a list API, wiring filter parsing into a handler, ... or debugging filter parsing/validation behavior") with concrete trigger phrases. A 4 would require the 'when' to be less explicit than it is.

Trigger Term Quality

Good natural-keyword coverage: "filterable fields", "list API", "filter parsing", "validation", "handler". It is not a 5 because common user variations such as "query params", "filter operators", or specific endpoint names are missing; not a 3 because the terms present are ones a user of this codebase would naturally say.

Distinctiveness Conflict Risk

Niche triggers ("AIP-style", "v3 list endpoints", "pkg/filter predicates") make false triggering unlikely, but "adding filterable fields to a list API" has minor overlap risk with the closely related /api TypeSpec-scaffolding skill. Not a 5 because of that overlap; not a 3 because the description is far more specific than a broad domain phrase.