---

name: mcaf-feature-spec description: "Create or update a feature spec under docs/Features/ using docs/templates/Feature-Template.md: business rules, user flows, system behaviour, Mermaid diagram(s), verification plan, and Definition of Done. Use before implementing a non-trivial feature or when behaviour changes; keep the spec executable (test flows + traceability to tests)." compatibility: "Requires repository write access; produces Markdown docs with Mermaid diagrams and executable verification steps."

MCAF: Feature Spec

Outputs

• docs/Features/<feature>.md (create or update)
• Update links from/to ADRs and architecture map when needed

Spec Quality (anti-guesswork checklist)

Write a spec that can be implemented and verified without guessing:

• No placeholders: avoid “TBD”, “later”, “etc.”; if something is unknown, list it as an explicit question.
• Concrete modules: use real module/boundary names from docs/Architecture/Overview.md.
• Rules are testable: numbered business rules with clear inputs → outputs (no vague adjectives).
• Flows are executable: scenarios include preconditions, steps, expected results (happy + negative + edge).
• Verification is real: commands copied from AGENTS.md, and scenarios mapped to test IDs.
• Stakeholders covered: Product / Dev / DevOps / QA each get the information they need to ship safely.

Workflow

1. Start from docs/Architecture/Overview.md to pick the affected module(s).
2. Create/update the feature doc using docs/templates/Feature-Template.md.
   • follow AGENTS.md scoping rules (do not scan the whole repo; use the architecture map to stay focused)
   • keep the feature’s ## Implementation plan (step-by-step) updated while executing
3. Define behaviour precisely:
   • purpose and scope (in/out)
   • business rules (numbered, testable)
   • primary flow + edge cases
4. Describe system behaviour in terms of entry points, reads/writes, side effects, idempotency, and errors.
5. Add a Mermaid diagram for the main flow (modules + interactions; keep it readable).
6. Write verification that can be executed:
   • test environment assumptions
   • concrete test flows (positive/negative/edge)
   • mapping to where tests live (or will live)
   • traceability: rules/flows → test IDs (so tests reflect the spec)
7. Keep Definition of Done strict:
   • behaviour covered by automated tests
   • static analysis clean
   • docs updated (feature + ADR + architecture overview if boundaries changed)

Guardrails

• If the feature introduces a new dependency/boundary, write an ADR and update docs/Architecture/Overview.md.
• Don’t hide decisions inside the feature doc: decisions go to ADRs.