agent's spreadsheet export crashed at the 1M-row limit and silently truncated the exceptions list

TL;DR

Spreadsheet formats cap rows, about a million in modern Excel, and exporters that hit the cap either crash or quietly write a partial file. A silently truncated exceptions list is dangerous because reviewers believe they saw everything. Export in chunks sized safely under the limit, write a manifest with expected and actual row counts per chunk, and validate completeness before anyone reviews. For large exception sets, a database or CSV review path beats spreadsheets anyway.

agent's spreadsheet export crashed at the 1M-row limit and silently truncated the exceptions list

Use this when

• The export crashes or the resulting file has far fewer rows than the exceptions list.
• The row count lands suspiciously near 1,048,576 or a similar round limit.
• Reviewers worked from the file believing it was complete.

Not for this skill when

• The export fails on small data. That is a different error; read its message.
• The file is complete but a viewer or email attachment truncated it in transit. Check the source file's own row count first.

Steps

1. Count the true exceptions in the system and compare with the exported file's row count. Verify: the shortfall is quantified and the limit is the plausible cause
2. Re-export in chunks under the limit, for example 500k rows each, with a manifest recording expected counts per chunk. Verify: chunk counts sum to the system count
3. Validate each chunk: row counts, and a spot check that the first and last exceptions of the full list appear in the chunks. Verify: the boundary items prove no silent gap
4. Deliver the chunks with the manifest and a note that no single file contains the whole list. Verify: reviewers can see completeness from the manifest
5. For recurring large lists, move review to CSV or a queryable table and keep spreadsheets for summaries. Verify: the next large export follows the new path by default

Variant phrasings

spreadsheet export 1M row limit truncated exceptions silently

The truncated-export phrasing.

agent export chunked rows manifest completeness check

When chunking the export.

Compatibility: Spreadsheet export limits in Excel-format exports from agent and reconciliation tooling.

Why it happens

The row limit is a format constant, and exporters handle it in the worst possible ways: some throw, some truncate, and the truncating ones often write a valid-looking file. The failure is therefore invisible at the point of consumption, which is why verification belongs in the export job itself, not in the reviewer's habits. Chunks plus a manifest make completeness a property of the deliverable rather than a hope.

Edge cases / pitfalls

• Excel's limit is 1,048,576 rows; older formats cap at 65,536, which fails far earlier and more confusingly.
• CSV has no row limit but spreadsheet apps still cap what they display; the manifest matters even for CSV review.
• A truncated file that drove past decisions may need a re-review note; check what was decided from the partial list.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_i4rKDHxijoA2rmfK0ZqJIQ