---
name: drawing-revision-diff
description: Compare two revisions of a drawing set (PDFs, or text exported from Bluebeam Revu through its MCP save_as_text tool) sheet by sheet - sheets added or removed, and every note, dimension, title or schedule line that changed - and turn it into a revision summary for the team. Use when a new drawing issue arrives and the user asks "what changed in this revision", "compara la revisión B con la C", to update a transmittal, check a contractor's claim, or prepare a change-order backup.
---

# Drawing revision diff (text level)

## Inputs
- The two revisions as PDFs (vector PDFs with real text; scanned sets need OCR first), or text exports.
- The sheet numbering pattern (e.g. `A-101`, `EST-03`); ask if unusual.

## Procedure
1. `pip install pypdf`. Run `python scripts/drawing_diff.py old.pdf new.pdf --sheet-pattern "<regex>" --out diff.md --csv diff.csv`.
2. With Bluebeam Revu + MCP (Bluebeam Max, Revu 21.9+): open each revision as the active document and use `save_as_text`, then compare the two text files with the same script. Bluebeam's own Compare Documents / Overlay Pages remain the tool for linework.
3. Classify each changed line: dimension, note/specification, title/scale, schedule row, revision table, other. Highlight changes that move money or time: dimensions, materials, quantities in schedules, new notes with "provide", "replace", "add".
4. Check the revision table/cloud on each changed sheet: a text change on a sheet whose revision letter did not change is an **unflagged change**; report it explicitly.
5. Draft the revision summary: sheet · what changed · flagged in the revision table (yes/no) · possible cost/time impact (to confirm).

## Output
- Summary table, unflagged changes first; the markdown and CSV files.

## Never
- Never conclude "no changes" from text alone; geometry changes are invisible to this method. Say so every time.
- Never assign cost or responsibility; mark "possible impact, to confirm by the team".