---
title: "What is flight recorder?"
description: "A flight recorder is a per-episode log of every command executed and every file diff produced, kept so a failed episode can be read rather than guessed at."
url: "https://www.promigence.ai/glossary/flight-recorder"
site: "Promigence"
---

# What is flight recorder?

A flight recorder is a per-episode log of every command executed and every file diff produced, kept so a failed episode can be read rather than guessed at.

Debugging a batch failure without one means re-running the episode and hoping it fails the same way. With one, the flagged episodes in a validity report are openable: exact commands, exit codes, output, and what changed on disk.

Promigence keeps each failed episode for 7 days by default, so you can open it or re-run it with `promigence run replay`.

## Related
- https://www.promigence.ai/glossary/validity-report
- https://www.promigence.ai/glossary/episode