Flow Debug

Find root cause. Do not fix. End with a failing test that proves the bug; then hand off to /flow-patch.

NO FIXES WITHOUT ROOT CAUSE FIRST
NO PRODUCTION FIXES IN THIS SKILL

1. Investigate

• Reproduce; read full errors/stacks
• Check recent changes (git log, diff)
• Trace to the real trigger — do not guess

2. Confirm with RED

Write the narrowest failing test (or substitute) that fails because of the bug. Follow flow-shared/references/tdd-red-green.md (RED only — stop before GREEN).