You Recorded the Incident. Now Prove Your Fix Actually Works.

Part 2 of Your Agent Failed in Prod. Good Luck Reproducing It.

This work was presented at the AI Engineer World's Fair 2026 by Susheem Koul and Tisha Chawla.

In Part 1 the agent deleted the wrong record at 9:04, and you could not make it happen again. The fix was not to force the model to be deterministic. It was to record the run: the exact prompt, the sampled completion, the tool calls, the retrieved chunks, the pinned model version. Freeze the run, not the model.

So you did that. The incident is now a file on disk. You can open it and see, precisely, what the agent decided that night.

Now comes the part nobody talks about. You still have to fix the bug. And you have to prove the fix works. This is where most teams quietly fall back into the swamp they just climbed out of.