--- name: acceptance-criteria description: Write testable acceptance criteria in Given\/When\/Then (Gherkin) format for stories, epics, and features. Use when defining acceptance criteria, writing test scenarios, or when user mentions "acceptance criteria", "Given\/When\/Then", "Gherkin", "test scenarios", or "AC". license: MIT compatibility: opencode metadata: domain: agile format: gherkin --- # Acceptance Criteria Writing Skill ```xml Write testable AC in Given\/When\/Then format<\/definition> Precondition\/context<\/given> Action\/trigger<\/when> Expected outcome<\/then> Additional outcomes<\/and> <\/format> Can be verified as pass\/fail<\/testable> No execution order dependency<\/independent> Exact expected behavior<\/specific> Covers one complete scenario<\/complete> <\/quality> Normal, successful flow<\/happy_path> Boundary conditions (min\/max\/empty)<\/edge_case> Invalid input, failures, no side effects<\/error_case> AuthN\/AuthZ, 403 Forbidden<\/security> NFR with measurable metrics (e.g., <200ms p95)<\/performance> <\/types> High-level checklist (Merchant can create product, Validation works)<\/prd> Feature-level checklist (All CRUD works, Events published, Coverage >80%)<\/epic> Detailed Given\/When\/Then for each scenario (AC1, AC2, AC3...)<\/story> <\/depth_by_artifact> Too vague → Define exact behavior<\/vague> Split into separate ACs<\/multiple_scenarios> Focus on WHAT, not HOW<\/implementation> Always include negative scenarios<\/missing_errors> Use measurable outcomes (<200ms, not "fast")<\/no_metrics> <\/common_mistakes> Given valid data, When POST, Then 201 Created<\/create> Given existing ID, When GET, Then 200 OK<\/read> Given existing ID, When PUT, Then 200 OK<\/update> Given existing ID, When DELETE, Then 204 No Content<\/delete> <\/crud> Given invalid field, When create\/update, Then 400 Bad Request<\/validation> Given user with role, When accessing resource, Then allowed\/denied<\/authorization> <\/templates> <\/acceptance_criteria> ``` --- ## Example: Story-Level AC ```markdown ## Acceptance Criteria ### AC1: Create product with valid data **Given** authenticated merchant with "product:create" permission **When** POST \/api\/v1\/products with valid payload **Then** 201 Created returned **And** product has generated UUID **And** product status is "pending" **And** "product.created" event published ### AC2: Reject invalid product data **Given** authenticated merchant **When** POST \/api\/v1\/products with missing "name" **Then** 400 Bad Request returned **And** error response contains validation details **And** no product is created ### AC3: Reject unauthorized access **Given** user without "product:create" permission **When** POST \/api\/v1\/products **Then** 403 Forbidden returned ``` See `template.md` for full format.