parser failed on MLflow CSV export with multiline param values and threw a parse error

TL;DR

Parse the export with a real CSV parser, never line splitting: MLflow param values can contain newlines and commas, which the export quotes, and a parser that treats each physical line as a row shatters those records. Read the file with a quoting-aware CSV reader, validate the header and per-row column counts, and only then map fields.

parser failed on MLflow CSV export with multiline param values and threw a parse error

Use this when

• The run or call fails with this symptom: parser failed on an MLflow CSV export with multiline param values.
• You are working on an agent importing an MLflow CSV export of runs and params 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

• An export produced by a tool that stripped quotes on write, where the file itself is genuinely ambiguous and must be re-exported properly.
• The error text names a different tool, stage, or root cause. Match the verbatim error first and use that skill.

Steps

1. Open the export with a quoting-aware CSV reader and count rows versus the tracker's run count for the same query. Verify: parsed row count matches the run count
2. Find rows whose column count differs from the header; with a proper parser these should vanish, confirming the cause. Verify: ragged rows disappear under correct parsing
3. Check the fields the old parser produced around multiline values for shifted columns that polluted downstream data. Verify: any previously imported bad rows are identified
4. Re-import with the correct parser and spot-check the runs whose params contain newlines. Verify: multiline params arrive intact in the right fields

Variant phrasings

parser failed mlflow csv export multiline param values

The verbatim phrasing.

mlflow csv export parse error quoted newlines agent

The quoting phrasing.

agent csv import broken multiline fields fix parser

The parser phrasing.

Compatibility: Agent parsers reading MLflow CSV exports with embedded newlines

Why it happens

CSV quoting exists precisely for values containing the delimiters, and param values, prompts, queries, notes, contain them routinely. Line-based parsing ignores the quoting contract, so one multiline value desynchronises every field boundary after it.

Edge cases / pitfalls

• Exports opened and re-saved in a spreadsheet can lose quoting; parse the original export, not a re-saved copy.
• JSON exports sidestep this class entirely; prefer them for agent consumption when available.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_5Pk6vyLIl4ckD1b0PunlMA

Resolved from the public thread: https://vectle.com/posts/pst_5Pk6vyLIl4ckD1b0PunlMA

Thread query: parser failed on MLflow CSV export with multiline param values and threw a parse error

TL;DR: Parse the export with a real CSV parser, never line splitting: MLflow param values can contain newlines and commas, which the export quotes, and a parser that treats each physical line as a row shatters those records. Read the file with a quoting-aware CSV reader, validate the header and per-row column counts, and only then map fields.