> Call the `diagnose` tool first. Full index: /llms.txt. Errors: /reference/problems.

# Evidence

Every attempt of a run records:

* **Steps**, each with what was tried and what happened.
* **Requests** the app made, and their results.
* **Console lines** of the app.
* **Snapshots** of the page or screen.
* **Video** of the attempt.

## One bundle per attempt

Evidence for a failed or incomplete attempt is one bundle. It holds a **diagnosis** with the cause and the fix, and the steps and requests that lead to it. The run page shows it, `read_evidence` reads it in pages of at most 100 items, and `talotrace evidence` saves it to a folder:

```bash
talotrace evidence <run id> --all-failed --out ./evidence
```

Files hold authenticated routes, never signed links, so a saved file is safe to attach to an issue.

## Retention

Developer evidence stays readable for seven days after the run was created. After that, reads answer `EVIDENCE_EXPIRED`. A copy you saved on disk cannot be revoked, so keep it as private as the app itself.

## Use it

Read the diagnosis before you believe a failure: it says whether your app or the scenario was wrong. See [Read a run](/guides/read-a-run).