What problem does it solve?
Diagnose fixes hard bugs and performance regressions by forcing a disciplined, evidence-driven workflow instead of guesswork.
Core Features & Use Cases
- Feedback-loop first: Build a deterministic pass/fail signal (tests, API/CLI scripts, headless browser assertions, trace replay, or a minimal harness) to make the bug debuggable.
- Reproduce before changing: Confirm the failure mode matches the user report and can be repeated reliably (or at a high failure rate for flaky issues).
- Ranked, falsifiable hypotheses: Generate 3–5 predictions and only then test them with targeted instrumentation.
- Instrument, then fix with regression: Change one variable at a time, validate with a minimized repro, and lock in correctness with a regression test when a proper seam exists.
- Cleanup and post-mortem: Remove instrumentation, validate the original scenario, and document the root cause and prevention strategy (including handoff when architecture blocks test seams).
Quick Start
Ask the agent to diagnose this by using a pass/fail feedback loop, reproducing the reported failure mode, ranking falsifiable hypotheses, instrumenting with targeted probes, applying the fix with a regression test if possible, and confirming the original scenario no longer reproduces.