[Cowork] Global Instructions are erased/reverted after returning to chat

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?

Subject: Critical Bug: Cowork Global Instructions Being Erased/Reverted
Product: Cowork (Research Preview)
Issue: Global instructions I save in Cowork settings are being automatically erased or reverted when I return to chat.
Steps to Reproduce:
Open Cowork settings and navigate to Global Instructions
Update the global instructions with new content
Save the changes and exit the settings menu
Immediately re-open settings to verify — the new instructions are present ✓
Return to the main chat interface and have a conversation with Claude
Go back to settings and check the global instructions again — the updates have been completely erased and reverted to the previous version ✗
Expected Behavior:
Global instructions should persist indefinitely once saved. They should not be overwritten or deleted when returning to chat.
Actual Behavior:
Changes to global instructions disappear after leaving the settings menu and returning to chat. The original instructions are restored, erasing all updates.
Frequency: This has occurred consistently across multiple attempts.
Impact: I cannot establish critical safety rules and file handling procedures because the settings don't persist. This blocks me from configuring Claude's behavior for my specific workflow needs.
Additional Context:
I've tried: saving multiple times, refreshing, restarting Cowork, clearing and re-entering instructions—none of these resolve the issue
The instructions disappear specifically after returning to chat, suggesting a sync or session-initialization issue
This is blocking critical setup for my Cowork workflow

What Should Happen?

Global instructions should persist indefinitely once saved. They should not be overwritten or deleted when returning to chat.

Error Messages/Logs

Steps to Reproduce

Open Cowork settings and navigate to Global Instructions
Update the global instructions with new content
Save the changes and exit the settings menu
Immediately re-open settings to verify — the new instructions are present ✓
Return to the main chat interface and have a conversation with Claude
Go back to settings and check the global instructions again — the updates have been completely erased and reverted to the previous version ✗

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Claude Sonnet 4.6

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

_No response_