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mcaf-feature-spec

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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).

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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.