Copilot Chat can corrupt a Claude Code conversation

[NSExceptional]

• Copilot Chat Extension Version:
• VS Code Version: 1.118.1
• OS Version: macOS 15.6
• Feature (e.g. agent/edit/ask mode): Agent, Claude mode
• Selected model (e.g. GPT 4.1, Claude 3.7 Sonnet): Claude 4.6 Sonnet
• Logs: Idk how to get the logs or what logs are needed

Steps to Reproduce:

1. Have a conversation in the Claude Code extension (in my case I was using Opus 4.7)
2. In between messages, switch to Copilot Chat and switch to Claude mode
3. Resume the chat from Claude Code in Copilot Chat with a new message
4. Claude will do some work and eventually "stop" in the middle of what it was doing
5. If you ask Claude why it stopped, it will appear to Claude like this is a new conversation
6. Reloading the window will reveal that the rest of the conversation history was completely lost

Screen recording of the aftermath of one such scenario:

Screen.Recording.2026-05-06.at.5.23.56.AM.h265.mp4

I'm not sure what part of the handoff from the official Claude Code extension to Copilot Chat is "breaking" the conversation history, but I was able to recover this very important chat by going into my home folder, finding the matching session file, and deleting everything after the "stop" message that indicated I hit my limit (between step 1 and 2 above).

[vs-code-engineering]

Thanks for creating this issue! It looks like you may be using an old version of VS Code; the latest stable release is 1.119.0. Please try upgrading to the latest version and checking whether this issue remains.

Happy Coding!

[NSExceptional]

I have since updated VS Code and the issue persists. Additionally it often reports "X" files changed" but shows Y files in the diff area