Conciseness

The body is lean and directive — field tables instead of prose, terse rules like "Use `resource.ParallelTest` by default. Use `resource.Test` only when tests share state" and "Do not mix `Check` (legacy) and `ConfigStateChecks` in the same step" — and it never explains concepts Claude already knows (no "what is Terraform" padding). Every section earns its tokens; fits the 'lean and efficient' anchor rather than score 4's 'minor instances of over-explanation'.

Actionability

Fully executable, copy-paste-ready Go for every common case: a complete test function, provider factory, config helpers with numbered format verbs, all five scenario patterns, custom exists/disappears StateCheck implementations, the shared state-lookup utility, a CheckDestroy TestCheckFunc, and PreCheck. Minor example-specific placeholders (example_widget) are appropriate for a patterns skill; not score 4 since no key detail is missing.

Workflow Clarity

The test lifecycle is explicitly sequenced ("plan → apply → refresh → final plan", then destroy and CheckDestroy, with the failure condition stated), and scenario patterns give ordered step compositions including the two-commit regression workflow. It falls short of 5 because there is no guidance on actually running the tests (e.g., TF_ACC=1, `go test` invocation) or a run → read failure → fix loop, leaving a checkpoint gap.

Progressive Disclosure

A clearly signaled "**References** (load when needed)" block lists three real, one-level-deep files with one-line descriptions (`references/checks.md`, `references/sweepers.md`, `references/ephemeral.md` — all verified present), and topics whose depth lives in those files (sweepers, ephemeral/echoprovider, full knownvalue catalog) are correctly kept out of the body. Matches the 'clear overview with well-signaled one-level-deep references' anchor; not 4 because navigation and content split are clean.

Specificity

Names many concrete capabilities — "test structure, TestCase/TestStep fields, ConfigStateChecks with custom statecheck.StateCheck implementations, plan checks, CompareValue for cross-step assertions, config helpers, import testing with ImportStateKind, sweepers, and scenario patterns (basic, update, disappears, validation, regression), and ephemeral resource testing with the echoprovider package" — with no meaningful coverage gaps, matching the 'multiple specific concrete actions; comprehensive coverage' anchor rather than the score-4 anchor's 'minor gaps'.

Completeness

Explicitly answers both questions: the what is the enumerated capability list above, and the when is "Use when writing, reviewing, or debugging provider acceptance tests, including questions about..." with concrete trigger phrases — exactly the score-5 anchor pattern. Not 4, because the when-clause is fully explicit rather than 'could be more specific'.

Trigger Term Quality

Trigger terms are the exact identifiers and phrases a provider developer would naturally use: "statecheck, plancheck, TestCheckFunc, CheckDestroy, ExpectError, import state verification, ephemeral resources, or how to structure test files", plus "acceptance tests" as the common synonym. Coverage includes API names, concepts, and natural-language phrasings, matching the score-5 anchor rather than score 4's 'a few natural terms missing'.

Distinctiveness Conflict Risk

The niche is tightly pinned to "Terraform provider acceptance test patterns using terraform-plugin-testing with the Plugin Framework", which is clearly distinguishable from general Terraform, general Go testing, and generic testing-pattern skills; trigger terms (statecheck, CheckDestroy, ephemeral resources) are unambiguous for this skill alone — minimal conflict risk.