Editing your files
When you attach one of your own files, Custodos can change that very file instead of rebuilding a new one. Letterhead, styles, formulas, charts and slide masters are kept. This page shows what works in each format and where the limits are.
Last checked on 28 September 2026
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When Custodos edits your file itself
Custodos edits the real file when all four conditions are met. Otherwise the model can only read the file and, if needed, create a new one, see Creating files.
| Condition | What applies |
|---|---|
| Format | PDF, Word (.docx, .docm), Excel (.xlsx, .xlsm) or PowerPoint (.pptx, .pptm). Older formats such as .xls and OpenDocument files can only be read. |
| Size | 4 MB at most |
| Origin | uploaded directly into the chat, or opened from the Company Brain with Edit in chat. Custodos keeps files from Google Drive, Microsoft 365 or Outlook as text only, and the original stays with the provider. |
| Model | a model with tools, see Models |
How an edit works
- 1
Attach the file
Attach the file as described under Attaching files. - 2
Describe the change
Say exactly what should change, for example “In the offer, replace the price 4,800 with 5,200 and the date with 1 October” or “Remove pages 3 to 5”. - 3
Download the result
While it works, the chat shows something like Editing Word file…. The changed file appears as a new card under the reply, usually with “-bearbeitet” added to its name. Your attached original stays unchanged.
What works in each format
Whatever you do not ask to change is kept. Before handover, an independent program opens edited Word and Excel files as a check; for PowerPoint, Custodos checks that every slide and note in the file opens. A file that fails this check is not handed out.
| Format | Possible | Not possible |
|---|---|---|
| Keep, remove, reorder and rotate pages, append other attached PDFs. The result may have up to 1,000 pages. | Changing text within a page. For that, the model can create a new document on request, without the original layout. | |
| Word | Replace words and sentences, including in tables, headers and footers, insert and delete paragraphs, append sections, with tracked changes if you wish | Moving text and changing the formatting of existing text |
| Excel | Set values and formulas in cells, clear ranges, append rows at the end | Inserting or deleting rows or columns in the middle, because that would break references in formulas |
| PowerPoint | Replace text on slides, delete slides, write speaker notes | Adding or moving slides, restyling text, changing text in charts, SmartArt and slide numbers |
Contracts with tracked changes
For Word files, Custodos can record every change as a tracked change. You then get the file back as a redline and accept or reject each change in Word. Ask explicitly for tracked changes, for example “Revise clause 7 with tracked changes”. Without that request, changes are applied directly.
The author of the changes is shown as “Custodos” in the file. If your workspace has its own branding, its name appears there instead.
Having Excel models reviewed
Custodos can review how an Excel file is built, the way a model reviewer would. Ask, for instance, “Check this model for errors”. The chat then shows Inspecting Excel model…. The model gets an overview of the sheets, hidden ones included, and finds:
- formula patterns per column, and places where a formula or a typed number breaks the pattern
- numbers typed into formulas, in other words hidden assumptions
- error values, circular references, named ranges and links to other files
Where this does not apply
- A deleted slide is not a redaction. When Custodos deletes a PowerPoint slide, it disappears from the presentation. Its charts and images may still remain inside the file. For confidential content, this is not a safe way to remove it.
- Replacing needs the exact wording. In Word and PowerPoint, Custodos only finds text that appears exactly like that within one line, including upper and lower case. A phrase split by a line break, or in Word by a tab, is not found.
- Larger files stay readable. Above 4 MB, Custodos keeps only the text. The model can then summarise the content or create a new file, but it cannot change your file.
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