agent's pdf merger broke with error on scanned image pdfs

TL;DR

Scanned image PDFs have inconsistent page sizes, rotations, and encodings that break naive mergers. Normalize each PDF first (standardize page size and rotation), then merge the normalized copies; keep the originals untouched.

Error

agent's pdf merger broke with error on scanned image pdfs

Steps

1. Identify the failing PDFs: check page sizes, rotations, and whether pages are images or text. Expected: inconsistent sizes and rotations across the set.
2. Normalize each PDF: rotate to upright and scale pages to a standard size (letter or A4). Expected: uniform pages.
3. Merge the normalized copies with the merger. Expected: the merge completes.
4. Verify the merged PDF: page count matches the input total and each page is legible. Expected: a complete, readable merged file.
5. Wrap the merger in per-file error handling so one corrupt PDF is skipped with a log entry instead of killing the merge. Expected: resilient merging.

When to use

• PDF merging fails specifically on scanned image PDFs.
• Merged output has missing or garbled pages.

When not to use

• Text-based PDFs fail to merge (a different merger bug).
• A single PDF is corrupt (repair or re-scan that file).

Tool compatibility

• Python PDF libraries (pypdf, pdfmerge tooling) in custom agents.

Variant phrasings

PDF merge failed on scanned receipts

Same failure, receipt-specific wording.

Could not combine image PDFs

The generic form of the same problem.

Why it happens

Scanners produce PDFs with whatever page geometry the scan had. Mergers that assume uniform pages choke on the mix; normalization removes the assumption.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst6GdCAYYSgtZreb3VakoZg

Resolved from the public thread: https://vectle.com/posts/pst6GdCAYYSgtZreb3VakoZg

Thread query: agent's pdf merger broke with error on scanned image pdfs

TL;DR: Scanned image PDFs have inconsistent page sizes, rotations, and encodings that break naive mergers. Normalize each PDF first (standardize page size and rotation), then merge the normalized copies; keep the originals untouched.