[BUG] API Error 400: Could not process image

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Dispatch mode always returns API Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"Could not process image"}} on every message sent.

The same account works fine in Dispatch on another Mac (office Mac mini). Chat and Code modes work normally on this machine.

What Should Happen?

Dispatch should respond normally without image processing errors.

Error Messages/Logs

Every message in Dispatch returns API Error 400: "Could not process image", regardless of content.

Steps to Reproduce

1. Open Cowork → Dispatch tab
2. Type any message and send
3. Error appears immediately: "Could not process image"

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

1.1.8629

Claude Code Version

1.1.8629

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

• Cowork version: 1.1.8629
• Device: Mac mini 2024, M4
• macOS version: (Tahoe 26.3（25D125）)
• Account: Max plan

• Updated to latest version (1.1.8629)
• Turned off "Computer use"
• Turned off "Allow all browser actions"
• Turned off "Keep awake"
• Completely uninstalled and reinstalled Cowork
• Same account works fine on another Mac (office machine)