## TL;DR
Parse the config as the YAML it is, with attention to how W and B writes it: run configs include typed values, nested structures, and sometimes anchors or custom formatting that a naive loader or a regex scraper mangles. Load with a full YAML parser, inspect the failing document around the reported line, and normalise typed wrappers, such as value objects, before reading fields.

```text
agent couldn't parse W&B run config YAML and failed with a config parse error
```

## Use this when
- The run or call fails with this symptom: agent could not parse a W and B run config YAML and failed with a config parse error.
- You are working on an agent reading W and B run configs exported as YAML and the failure repeats on the same run or configuration.
- You need the failing run, call, or stage isolated before changing code or thresholds.

## Not for this skill when
- A config file that is genuinely malformed from a hand edit, where the fix is correcting the file rather than the parser.
- The error text names a different tool, stage, or root cause. Match the verbatim error first and use that skill.

## Steps
1. Load the file with a standard YAML parser and capture the exact line and column of the parse failure. Verify: the failure location is known
2. Inspect that region for the usual W and B shapes: nested value objects, anchors, or unquoted strings containing colons. Verify: the offending construct is identified
3. Parse through a normalisation step that unwraps typed value objects into plain scalars after loading. Verify: the config loads into plain fields
4. Validate the parsed result by checking the fields the agent needs exist with expected types before use. Verify: required fields are present and typed correctly

## Variant phrasings
### agent could not parse wandb run config yaml
The verbatim phrasing.
### wandb config yaml parse error agent value objects
The value-object phrasing.
### agent failed reading run config yaml anchors fix
The anchors phrasing.

Compatibility: Agent parsers reading Weights and Biases run config files in YAML

## Why it happens
Run configs are written for the tracker's own reader, not for generic tools, so they use the corners of YAML that simple parsers and hand-rolled splitting handle badly. The parse error is a format mismatch between writer and reader, not corrupt data.

## Edge cases / pitfalls
- Prefer the tracker's API or its own export for config data when available; files are the fallback, not the interface.
- A config with duplicate keys loads differently across parsers; check for duplicates if values look wrong after a clean parse.

## Provenance

Resolved from the public thread: https://vectle.com/posts/pst_uQeCIgV2QUA76pe3Z3zfEA