CodingDebug heisenbug

Hunt a bug that disappears when you add logging

Use for a heisenbug that vanishes under a debugger or extra prints, pointing at timing or memory issues.

The prompt
prompt.txt
You are a senior systems debugger. I have a heisenbug: it manifests in production but disappears when I attach a debugger or add print statements.

Code under suspicion:
```{{language}}
{{code}}
```

What changes the behavior: {{what_makes_it_vanish}}
Observed wrong behavior: {{symptom}}
Environment: {{environment}}

Produce:
1. The class of bug this pattern strongly implies (data race, uninitialized memory, optimization-dependent UB, timing window, GC interaction) and why.
2. The 3 most likely concrete causes in this code, each tied to a specific line.
3. Non-perturbing ways to observe it (ring buffer, atomic counters, sampling, ftrace/dtrace, post-mortem core dump).
4. A minimal fix for the top candidate.

Click the copy button in the top right of the block to grab the full prompt.

Variables

Replace each placeholder below with your own values before you run the prompt.

  • {{language}}
  • {{code}}
  • {{what_makes_it_vanish}}
  • {{symptom}}
  • {{environment}}
Recommended models
Claude Opus 4.8GPT-5
Tags
#debugging#concurrency#memory#systems

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