Guide
Upload large files from an agent over MCP
agentdrive accepts files up to 25 MB on the free drive and 1 GB on the Drive plan. Above 2 MB, the agent uploads in chunks with save_file. Each call carries at most 2,000,000 decoded bytes.
Get your free drive
Sign in at useagentdrive.com/signin. Your first drive is created for you: 500 MB, 25 MB per file.
Get a free driveStart the upload
The first save_file call states the full size and sends the first chunk as base64.
save_file name="export.zip" encoding="base64" total_bytes=7340032 content="<first 2,000,000 bytes>"
Continue until saved
Each reply returns upload_id and next_offset. Send the next chunk with both, and repeat.
save_file name="export.zip" encoding="base64" upload_id="<id>" offset=<next_offset> content="<next chunk>"
Check the status
The upload is done only when a reply says status=saved. That reply carries the file ID.
Limits that apply
A pending upload reserves its full size against the drive quota. It expires after 1 hour if not finished.
An account holds at most 20 pending uploads. Text above 400 KB must use base64.
An optional request_id, a UUID, makes a retried call safe. The same request never saves twice.
Reading a large file back
read_file returns up to 2,000,000 bytes per call. Follow next_offset until the file ends.
Base64 reads preserve every byte. Whole-file UTF-8 reads are limited to 400 KB.
Questions
- What is the largest file agentdrive takes?
- 25 MB per file on the free drive. 1 GB per file on the Drive plan, $9/month.
- What happens if the agent stops mid-upload?
- The pending upload keeps its reserved space for 1 hour, then expires. Nothing partial appears in the drive.
- Does the agent need special code for chunks?
- No. The tool description tells the agent how to continue. Most agents follow next_offset without extra prompting.
- Do large files get a link too?
- Yes. get_file_link works for any saved file. Files the browser cannot show are offered as a download.