Parallel MCP tools execution triggers multiple oauth logins

[sergii-vashchyshchuk]

A recent upgrade allowing running multiple MCP tools in parallel has an ugly side-effect. If an mcp server requires oauth login (not authenticated, token expired, 401 from a tool call) and an agent calls multiple tools in parallel, it triggers multiple oauth login popups one after another.

• Copilot Chat Extension Version: 0.33.2
• VS Code Version: 1.106.1
• OS Version: doesn't matter
• Feature (e.g. agent/edit/ask mode): agent
• Selected model (e.g. GPT 4.1, Claude 3.7 Sonnet): all
• Logs:

Steps to Reproduce:

1. Connect an mcp server which requires oauth
2. Don't login or wait for token to be expired
3. Ask agent to do something that requires calling multiple tools in parallel

[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 1.106.2. Please try upgrading to the latest version and checking whether this issue remains.

Happy Coding!

[connor4312]

What experience would you expect here?

[sergii-vashchyshchuk]

1 oauth login, all tools wait for the token rather than triggering N oauth logins

[connor4312]

We make the tool calls themselves in parallel, and I'm guessing each of those requests sees there is no auth and then starts trying to do an auth flow independently. Tyler James Leonhardt (@TylerLeonhardt) should we put a queue around the auth flow to avoid this?

[connor4312]

actually, this should already be guarded by parallelism on the server start. And I don't repro this with the Github MCP.

25-12-1cdf7e48-5e45-4d80-90cc-4f3952e94926.mp4

Could you share what server you see this happening with?

[connor4312]

Or, actually, maybe this could happen with Step-Up auth if each of those three requests need to reauth. That would not be serialized by the server starting and would need auth serialization

[TylerLeonhardt]

should we put a queue around the auth flow to avoid this?

The possibility of one flow never finishing because of whatever reason (user closing the tab in their browser) makes this tricky.

[TylerLeonhardt]

Maybe we can do better and have MCP requests to start their auth in the Chat... .that way we could show multiple at the same time.