Debug with an Agent Using a Hypothesis-Driven Loop
Guide a coding agent to debug systematically — form a hypothesis, add instrumentation, test it, narrow down — instead of random edits.
Find the real root cause faster by forcing structured, evidence-based debugging rather than shotgun fixes.
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Prompt objective
Find the real root cause faster by forcing structured, evidence-based debugging rather than shotgun fixes.
Real use case
An intermittent production bug appears under load. A coding agent keeps applying speculative patches that don't fix it and sometimes make it worse.
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Prompt
Act as a debugging specialist working as a coding agent. Use a strict hypothesis-driven loop. Do not change behavior until you can explain the cause. Bug report: [SYMPTOMS, WHEN IT HAPPENS, ERROR/STACK TRACE] Environment: [STACK, RECENT CHANGES] What has already been tried: [LIST] Loop: 1. State the single most likely hypothesis for the root cause and why. 2. Describe the cheapest experiment (log line, test, query, repro) that would confirm or kill that hypothesis. Add only instrumentation, no fixes. 3. Predict what you expect to observe if the hypothesis is true vs false. 4. After I share the observation, update: confirmed, refuted, or inconclusive — and pick the next hypothesis. 5. Repeat until the root cause is proven. Only once the cause is confirmed: propose the minimal fix, the regression test that would have caught it, and any cleanup of the temporary instrumentation. Start at step 1.
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