Chat: Upload & Attach Files
Attach documents and images to a chat so the agent can read them.
Attach files to a chat so the assistant can read them alongside your message — a markup PDF, a photo of a framing condition, a loads spreadsheet, or a Word spec. This page covers what you can attach, the limits, and how attachments are handled on a turn.
What you can attach#
The assistant accepts a fixed set of file types. Anything outside this list is rejected at upload.
| Type | Extensions |
|---|---|
.pdf | |
| Images | .png, .jpg, .jpeg, .webp, .gif |
| Spreadsheets | .csv, .xlsx |
| Documents | .docx |
PDFs and images are read by the model directly. Office files (.csv, .xlsx, .docx) are opened in a code-execution sandbox, so the assistant can parse a spreadsheet or pull text from a document.
If a file is rejected as the wrong type, check the extension. Accepted types are PDF, images, CSV, XLSX, and DOCX.
Limits#
- 10 MB maximum per file.
- 20 attachments per chat (counted against the open conversation).
Oversize files are refused before upload, and hitting the per-chat attachment limit returns a clear message — remove a file or start a new chat to free up room.
How attachments work on a turn#
- Pick a file in the chat composer (before or during a conversation). It's stored privately to your account.
- When you send the message that references the file, it's attached to that turn and sent to the model for that live turn.
- Follow-up turns reuse the already-uploaded file without re-sending the bytes.
Attachments are owner-private: only you can preview, download, or remove your own files. There is no firm-level sharing of chat attachments.
Mention what you want done with a file in the same message. "Read the loads on page 2 of this PDF and set up a beam calc" works better than uploading silently.
What happens on resume#
When you reopen a past conversation from Chat History, file cards still show on your earlier messages so you can see what was attached — but those historical files are display-only and are not re-sent to the model. To have the assistant work with a file again, attach it to a fresh message.
Removing an attachment#
Remove a file from the composer before sending and it won't be used. Removing a file is a soft delete scoped to your account, so it disappears from your view immediately.
Where to use this#
File attachments are part of the engineer assistant chat. For an overview of the assistant itself — how to open it, what it can do, and the model picker — see Engineer Chat Assistant. You can also send files by email to your agent.