[Bug] File uploads not landing in workspace on chat.z.ai web app

Bug Description

Files uploaded via the chat.z.ai web application are not being persisted to the expected filesystem location (/home/z/my-project/upload/), despite the IM gateway reporting successful uploads.

Expected Behavior

When a user uploads a file through the chat.z.ai web interface:

1. The file should be saved to /home/z/my-project/upload/
2. The agent should be able to access and read the uploaded file
3. The file should persist for the duration of the session

Actual Behavior

1. IM Gateway reports upload as successful — The gateway metadata indicates a file was uploaded
2. File does NOT appear on filesystem — The /home/z/my-project/upload/ directory remains empty after upload
3. Agent cannot access file — Agent reports: "The file you uploaded is not present at /home/z/my-project/upload/ despite the IM gateway reporting it as uploaded"
4. Agent claims workspace cleared — In some cases, the agent also reports that its workspace has been cleared/reset

Environment Details

• Platform: chat.z.ai web application
• Session ID: web-5a57868c-771e-4985-a203-277ff0668cd2
• Chat ID: b4591a2a-2718-4523-80c7-4165eee115ef
• Channel: zai-web
• Trace ID: 19fa3ff44d60189d
• Expected Upload Path: /home/z/my-project/upload/
• Directory Status: Exists (drwxrwxrwx) but empty
• Timestamp of Issue: 2026-07-27

Reproduction Steps

1. Open chat.z.ai web application
2. Start a new conversation with an agent
3. Upload a file using the file upload feature
4. Observe that the IM gateway indicates successful upload
5. Check /home/z/my-project/upload/ — file is missing
6. Agent responds claiming it cannot see/access the uploaded file

Impact

• High — File upload functionality is completely broken for web app users
• Users cannot:
  • Upload documents for analysis
  • Provide images for processing
  • Attach any files for agent interaction
• This affects all use cases requiring file input (document analysis, image processing, data processing, etc.)

Error Messages Observed

⚠️ Environment bug notice: The file you uploaded is not present at /home/z/my-project/upload/ 
despite the IM gateway reporting it as uploaded. The upload didn't actually land on the filesystem — 
the upload folder is empty.

Suggested Investigation Areas

1. File Storage Pipeline — Check if there's a breakdown between:

   • IM Gateway receiving the file
   • File being written to disk
   • Permission issues preventing write

2. Container/Volume Mounting — If running in containerized environment:

   • Verify volume mount for /home/z/my-project/upload/
   • Check if writes are happening but not persisting

3. Gateway-to-Agent Handoff — Verify:

   • File metadata is correctly passed from gateway to agent
   • Timing issues (agent checking before write completes)
   • Race conditions in file availability

4. Workspace Persistence — Investigate agent claims of "workspace cleared":

   • Session lifecycle management
   • Workspace reset between interactions
   • State management issues

Reporter Information

• Source: Discord (#feedback channel)
• Reporter: rousevv
• Original Report Link: https://discordapp.com/channels/1346756824233148527/1531306147104161802

This issue was submitted on behalf of user feedback from Discord.

The report names no repository files, tests, or entry points. Start by reproducing the upload through chat.z.ai and tracing whether the gateway writes to /home/z/my-project/upload/ and whether the agent receives the file; done means uploaded files are present, readable by the agent, and persist for the session.