diagnosing-bugslisted

# Diagnosing Bugs A discipline for hard bugs. Skip phases only when explicitly justified. When exploring the codebase, read the glossary (`docs/agents/domain.md` gives the layout; by default `GLOSSARY.md` at the root, if it exists) to get a clear mental model of the relevant modules, and check ADRs in the area you're touching. **Start from prior attempts.** If the user says they have been trying, ask what they tried before you start, so you skip their dead ends. If they link an issue, read the whole thread, latest comments first: they often carry newer repro steps or a different suspect. Run `git log --oneline -10 -- <file>` on the files you read to see what changed recently. ## Redact This skill has you show commands, outputs and captured artifacts. **Redact every secret first**: write `<REDACTED>` in its place. Build loops against env vars, so the credential stays in the environment rather than in what you show. Captured artifacts carry auth headers: quote only the lines that carry the signal. If the redacted output is not enough to diagnose the bug, say so and ask the user. ## Phase 1: Build a feedback loop **This is the skill.** Everything else is mechanical. If you have a **tight** pass/fail signal for the bug (one that goes red on _this_ bug), you will find the cause; bisection, hypothesis-testing, and instrumentation all just consume it. If you don't have one, no amount of staring at code will save you. Spend disproportionate effort here. **Be aggressive. Be c