## TL;DR
Recover metrics from the run, not from the truncated file alone: dvclive metrics JSON was cut mid-write by the training crash, so salvage the complete records before the truncation point, and treat the run as crashed rather than reading the file as finished. A truncated JSON file holds a true prefix and a missing rest. Reporting from it without flagging the crash understates the run and hides the failure that matters.

```text
agent couldnt parse dvclive metrics json after training crash truncated file error
```

## Use this when
- The check or run fails with this symptom: an agent cannot parse dvclive metrics JSON after a training crash truncated the file.
- You are working on an agent workflow reading dvclive metrics from completed and crashed runs and the failure repeats on the same data or configuration.
- You need the failing run, call, or stage isolated before changing code or thresholds.

## Not for this skill when
- A complete file that fails parsing for a different reason, such as a hand edit, which needs the edit reverted rather than crash handling.
- The error text names a different tool, stage, or root cause. Match the verbatim error first and use that skill.

## Steps
1. Check the training run status and logs for the crash. Verify: the run ended abnormally at the truncation time
2. Parse the file incrementally and keep the records that decode fully. Verify: the salvageable metric history is recovered with its last complete step
3. Mark the run as crashed in the workflow output, with the crash point. Verify: downstream summaries exclude it from completed comparisons
4. Fix the logging to write metrics through dvclive normal flush behaviour and to close the file on exit handlers where possible. Verify: a later crash leaves a cleaner prefix
5. Rerun or resume the training as the project decides. Verify: a complete metrics file replaces the truncated one

## Variant phrasings
### agent couldnt parse dvclive metrics json training crash truncated
The shorter phrasing focused on the named failure.
### dvclive metrics truncated file parse error
The symptom phrasing a searcher tries next.
### truncated dvclive metrics salvage fix
The variant naming the failing stage or tool directly.

Compatibility: dvclive metrics files, crash recovery in agent run analysis

## Why it happens
dvclive appends metrics as training proceeds, and a hard crash, a kill, or a spot reclamation can stop the process mid-write. The resulting file is not corrupt data; it is an interrupted stream, and parsers that demand a whole valid document report a format error instead of a crashed run.

## Edge cases / pitfalls
- Do not pad or close the JSON by hand and present it as the run record; label salvaged data as partial wherever it is used.
- The last complete step is a useful lower bound for progress reporting, never a final result.

## Provenance

Resolved from the public thread: https://vectle.com/posts/pst_qZPRNNi4k75oHVwSRMllAQ