Waterfall Development

Strict phase gate enforcement for waterfall workflow. Requires the feature-file skill for artifact management.

Phases

Requirements → Design → Implementation → Testing → Complete

Activation

| Condition | Action | |-----------|--------| | features.yml exists | Activate, validate gates | | User invokes skill, no features.yml | Create features.yml via feature-file skill, then activate | | No features.yml, not invoked | Do not activate |

Workflow

1. Run ./scripts/validate-gates.py
2. If errors: Print errors, STOP
3. Identify target feature and current phase
4. Block work that doesn't match current phase
5. Before phase transitions: Re-validate target phase gates

Gates

See references/phase-gates.md for fix instructions.

| Gate | Transition | Criteria | |------|------------|----------| | G1 | → Design | Feature has ≥1 requirement | | G2 | → Design | All requirements have descriptions | | G3 | → Implementation | decisions field exists | | G4 | → Testing | All requirements In-Progress or Complete | | G5 | → Complete | All requirements Complete + tested-by + all tests passing |

Agent Usage

Use sub-agents for verification tasks that require codebase exploration:

Before Design phase: Verify requirements are complete by examining codebase and user request for implicit requirements.

Before Complete phase: Verify test coverage by checking all requirements have corresponding tests and tested-by references.

Error Handling

Gate failures print terse errors. No bypass mechanism.