Go troubleshooting

No fixes without a root cause. Symptom patches create new bugs. This is especially true under time pressure.

Feedback loop first

Before forming any hypothesis, build the tightest pass/fail signal you can — fast (reruns in seconds), deterministic (same result every run), sharp (fails close to the fault). Jumping straight to a hypothesis is the exact failure this discipline prevents.

Prefer the tightest loop you can build: