/feature
The core command. Four phases, each with a different AI role.
When to use
Section titled “When to use”- You know the problem and need to define the solution
- Before any feature larger than ~300 lines
- When you need an auditable trail of design decisions
The four phases
Section titled “The four phases”Phase 1: Intent
Section titled “Phase 1: Intent”AI role: Adversarial interviewer
Five forcing-function questions, asked one at a time:
- What problem does this solve? Not what it builds — what problem goes away.
- How will we know it worked? An existing metric that will move.
- What’s out of scope? Draw the boundary now, not during implementation.
- What must NOT happen? Negative requirements are more durable than positive ones.
- Pre-mortem. It’s six months from now and this failed. What went wrong?
The AI pushes back on vague answers and refuses to move on until the thinking is substantive.
Phase 2: Behavioral Spec
Section titled “Phase 2: Behavioral Spec”AI role: Mechanism designer
Five-level funnel:
- User stories (who does what)
- Mechanism — why will this approach actually work? Not how — why.
- States and transitions
- Concurrency — what happens when two of these run at the same time?
- Error cases — what can go wrong and what happens when it does
Phase 3: Design Conversation
Section titled “Phase 3: Design Conversation”AI role: Research partner
The AI researches the codebase, presents options and tradeoffs. You make the decisions. Reads specs/ARCHITECTURE.md if it exists.
Phase 4: Implementation Design
Section titled “Phase 4: Implementation Design”AI role: Codebase critic
Proposes architecture AND challenges the codebase itself. Flags inconsistent patterns, structural rot, ambiguous placement. Cleanup becomes a prerequisite.
Thinking records
Section titled “Thinking records”Every phase transition produces a thinking record — what was decided, why, what was rejected, what was skipped. These go into the final spec as an audit trail.
Output
Section titled “Output”specs/[feature-name].md — the spec with embedded thinking records. Also appends to specs/DECISIONS.md.
Next step
Section titled “Next step”/plan to break it into buildable phases.