MCP servers show as connected via /mcp after /new but tools are not available to the agent.

[isochronous]

Describe the bug

Agents lose the ability to access MCP servers after starting a new session via /new, even though MCP servers show as connected and available.

Affected version

No response

Steps to reproduce the behavior

1. Open copilot fresh, with an MCP server pre-configured in ~/.copilot/mcp-config.json
2. Verify that your agent can use one of the server's tools via a prompt of your choice.
3. Start a new session with /new
4. Run /mcp show to verify that server is still connected and tools are enabled.
5. Run the same prompt
6. Agent will be like "I don't know what you're talking about, I don't have that tool"

Expected behavior

Agents should always be able to access connected MCP servers as long as they have not been prevented from doing so via configuration.

Additional context

• Windows 11 x64
• Running in Kali linux in a WSL2 wrapper
• Using windows terminal to run bash (in kali) launched via powershell
• I have two MCP servers installed, one for atlassian and one for gitlab. Agents can access neither after a new session is started. Exiting and re-launching copilot temporarily fixes the issue.