Boundary: Orchestrator flow — chains investigate-bug (entry point + RCA via diagnose-root) → develop-tdd → validate-fix. Does not implement RCA or write bug files directly.

Orchestrates fix_bug flow without mixing epic build state.

HARD GATE — Set specs/state.yaml active_flow: fix_bug and bug_cycle.current_step: 1 before starting.

Valid entry without a user-reported bug when:

• Preflight or CI is red at kickoff or verify-work
• Golden suite or project baseline is red (bash scripts/run-verification-gates.sh or equivalent)
• A reproducible gate failure during unrelated epic work exceeds quick-fix guardrails

Create specs/bugs/BUG-*.md via investigate-bug (or inline in fix-bug step 1) describing the gate failure, then run the standard fix_bug chain.

Track progress via specs/state.yaml bug_cycle:

• bug_cycle.current_step: current step (1–5)
• bug_cycle.completed_steps: completed step numbers
• handoff.next_skill: skill for the current step
• On resume, read bug_cycle.current_step and continue from there

1. Step 1 — investigate-bug: If no specs/bugs/BUG-*.md, run investigate-bug first — it handles history check, RCA (via diagnose-root), fix approach, and writes the bug file. Increment bug_cycle.current_step to 2 on completion.
2. Step 2 — diagnose-root: Run 4-phase RCA (reproduce → isolate → hypothesize → verify). Record findings in the bug file. Increment to step 3.
3. Step 3 — develop-tdd: develop-tdd against the bug file’s verify steps. Increment to step 4 on all-green.
4. Step 4 — validate-fix: validate-fix — re-run failing test, full suite, typecheck, lint. Increment to step 5.
5. Step 5 — release-branch: Land the fix via release-branch. Clear bug_cycle and active_flow when done.

One markdown file per bug with frontmatter:

---
bug_id: BUG-001
status: open
severity: high
scope: api
title: Short title
---

→ verify: test -d specs/bugs && test -f scripts/run-skill-verify.sh