diagnose

name	diagnose
description	Use when something is broken, failing, slow, throwing, flaky, or behaving unexpectedly.

Diagnose

Build a tight failing loop and find root cause before proposing fixes.

Boundary

Diagnose owns investigation until there is a root cause and a red-capable loop. Do not jump to build while the failure is still a theory.

Process

1. Reproduce the exact user-visible symptom.
2. Build the tightest possible loop that can go red for this bug.
3. Minimize the scenario until remaining inputs, state, and steps are load-bearing.
4. Form ranked, falsifiable hypotheses before changing production code.
5. Instrument one boundary or variable at a time.
6. When root cause is identified, create or preserve the regression signal.
7. Move to build for the fix.

Reference Branches

• Use diagnosing-bugs for hard bugs, performance regressions, flakiness, and feedback-loop construction.
• Use systematic-debugging for strict root-cause discipline and multi-layer evidence gathering.

Specialist Branches

• firecrawl when current external docs, issue trackers, or release notes may explain the failure.
• vercel-react-best-practices when the failure is React/Next performance or data-flow related.

Completion

Done when there is one command or reliable loop that demonstrates the bug, a clear root-cause hypothesis supported by evidence, and a path to a regression test or documented reason no correct seam exists.