Attaching files and images
Attach PDFs, Office files, text and images to a chat. They stay available for the whole chat until you remove them.
Instead of copying text into the message box, attach the file itself: a contract as a PDF, an Excel analysis, a screenshot of an error message. The model reads the content and answers your questions about it, even many messages later.
Attach a file
Add the file
Click the plus sign Add in the message box and choose Attach file. You can also drag files onto the chat, or paste a screenshot into the message box with Ctrl + V (Mac: Cmd + V).
Check the card
Each file appears as a card above the message box. For documents it shows how many characters of text Custodos read; for images it shows Image. The cross on the card removes the file again.
Ask and send
Write your question and send it. A message can also consist of a file alone, such as a screenshot with no text.
What you can attach
| Kind | Formats | Note |
|---|---|---|
| Only PDFs with a text layer. Pure scans are refused. | ||
| Word | .docx, .docm | |
| Excel and tables | .xlsx, .xlsm, .xls, .ods, .csv, .tsv | |
| PowerPoint | .pptx, .pptm | The text of the slides. |
| Text and data | .txt, .md, .json, .xml, .yaml, .html and more | |
| Code | Common source files, such as .py, .js or .sql | |
| Images | .png, .jpg, .webp, .gif | Only models that can read images see them. |
From a document Custodos reads the text. So the model sees the content, not the layout. When you upload a PDF, Word or Excel file directly, Custodos also keeps the original so the model can edit the file later. More in Creating and editing documents.
Older or less common formats such as .doc, .ppt, .rtf, .odt, .pages or .msg cannot be read. Save the file as PDF, Word, Excel or PowerPoint and upload it again. The same goes for images in .heic, .avif, .tif, .bmp or .svg: save them as PNG or JPEG. Some browsers, such as Safari, convert iPhone photos in .heic format to JPEG themselves during upload.
Files stay with the whole chat
Every attached file is sent to the model with every later message, not only with the one you uploaded it with. So in your ninth message you can still ask about a clause in the PDF from the first.
When you no longer need a file, remove it: hover over the file above your message and click the cross. The file is no longer sent, and your message text stays.
Images and screenshots
Images are sent as images to models that can read them. If the chosen model cannot, a note under the cards says that the model only sees the file names. Switch the model in that case, see Choosing a model.
When you upload an image, Custodos scales it to at most 1,568 pixels on the longest side and removes metadata such as where it was taken. An image belongs to the message you sent it with. In long chats the newest images are sent. Older ones stay in the chat, and the model is only told that they exist and what they are called.
Images cannot be checked for personal data. So depending on your settings:
| Situation | What happens |
|---|---|
| Protection mode Pseudonymise or Off | Images are allowed. Their content is not checked. |
| Protection mode Block | Images are refused. Admins see an Open settings link next to the message. |
| Chat in security mode | Images are refused. Use a regular chat for them. |
| The setting becomes stricter later | Images already in the chat are no longer sent to the model. |
Data protection in documents
If your workspace is set to Pseudonymise, Custodos checks the text of every file when you upload it and replaces detected values such as names or IBANs with placeholders before sending. The review panel lists them under In attachments. If it is set to Block, a file containing protected data is not accepted. More in Protecting personal data in chat.
Files from connected accounts
If you have connected Google Drive, Microsoft 365 or Outlook, these services also appear in the Add menu. A service marked Connect is not connected yet: one click takes you through connecting it and back to the chat.
- Google Drive: pick up to 5 files at once in Google's dialog.
- Microsoft 365: browse OneDrive and SharePoint and pick a file.
- Outlook: find an email and take its message text or an attachment.
Custodos takes documents from these services as text only. The original stays with the provider, so the model cannot edit it. Sizes, formats and data protection work as for uploads. More in Integrations overview.
Best practices
- Attach documents instead of pasting text. Tables and sections stay together, and the model can also edit the file later.
- Give files clear names such as "Fee-Schedule-2026.pdf". The model sees the names and can refer to them in its answer.
- Use a Company Brain for documents the whole team needs again and again, instead of attaching them to every chat.
Frequently asked questions
The PDF only contains images of the pages, for example from a scanner. Attach the pages as images or paste the text directly. For documents you need more often: a brain can read scanned pages, see Adding sources.
Either the chosen model cannot read images (a note under the cards then says so), or the chat holds so many images that older ones are no longer sent. Switch the model or start a new chat for new images.
No. People reading a shared chat only see the names of your attached files, not their content. Files and images generated in the answers are visible, though. Details in Sharing and finding chats.
Next steps
Have Word, Excel and PDF files changed right in the chat.
Protecting personal data in chatWhat happens to names and identifiers in your files.
Integrations overviewConnect Google Drive, Microsoft 365 and Outlook.
Company Brain overviewWhen a brain works better than an attachment.
Choosing a model
Use Auto or pick a specific model, see credit usage and where it runs at a glance, and learn why a model may be missing.
Creating and editing documents
Have Word, Excel, PowerPoint and PDF files created, or change your own files in the chat with letterhead, formulas and formatting intact.