## TL;DR
Parse the YAML with anchors enabled and resolved: Polyaxon timeline YAML uses anchors and aliases to reuse blocks, so load it with a full YAML parser that resolves references, instead of a line parser or a loader that rejects anchors. Anchors are standard YAML. The parse failure means the agent tooling treated the file as simple key value text or used a restricted loader, not that the timeline file is wrong.

```text
agent couldnt parse Polyaxon timeline yaml with anchors error parsing failure
```

## Use this when
- The check or run fails with this symptom: an agent cannot parse Polyaxon timeline YAML with anchors.
- You are working on an agent workflow reading Polyaxon pipeline or timeline definitions 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 YAML file with a genuine syntax error beyond anchors, which a full parser will locate precisely instead of the agent guessing.
- 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. Verify: the document parses and anchors resolve to their values
2. Inspect the resolved structure for the timeline stages. Verify: stages and their reused blocks are present
3. Update the agent parser to the full loader for YAML inputs. Verify: other anchored files parse without special handling
4. Compare a resolved block against its anchor definition. Verify: reused values match the anchor source
5. Keep a small anchored YAML fixture for the parser. Verify: a future loader change is caught by the fixture

## Variant phrasings
### agent couldnt parse polyaxon timeline yaml anchors error
The shorter phrasing focused on the named failure.
### polyaxon yaml anchors parsing failure agent
The symptom phrasing a searcher tries next.
### yaml anchors full parser fix
The variant naming the failing stage or tool directly.

Compatibility: Polyaxon YAML pipeline definitions, YAML anchors and aliases, agent parsing workflows

## Why it happens
Polyaxon definitions use anchors to keep repeated stage configuration in one place, which is idiomatic YAML. Simple parsers, restricted safe loaders in some configurations, and regex based readers all fail on the reference syntax, and the agent reports the file as unparsable rather than its own reader as limited.

## Edge cases / pitfalls
- Merging anchor content by hand invites drift from the source; always resolve programmatically.
- When sharing the parsed result, note that anchors were resolved, since the flat form is much larger than the file.

## Provenance

Resolved from the public thread: https://vectle.com/posts/pst_vdNuhA2dhHcHM3oraTXedw