OAuth failure with MCP connector for ChatGPT and Claude (Claude Desktop works, Claude Remote fails)

[kulawydzik]

The problem

The MCP connector fails during the OAuth flow for both ChatGPT and Claude (remote / web).
Interestingly, Claude Desktop works with the same MCP configuration, but Claude Remote (Anthropic web) does not. ChatGPT also fails. In both failing cases, the flow starts and then errors out on the OAuth callback.

What version of Home Assistant Core has the issue?

core-2025.10.1

What was the last working version of Home Assistant Core?

No response

What type of installation are you running?

Home Assistant OS

Integration causing the issue

mcp_server

Link to integration documentation on our website

https://www.home-assistant.io/integrations/mcp_server/

Diagnostics information

No response

Example YAML snippet

Anything in the logs that might be useful for us?

Additional information

No response

[home-assistant]

Hey there @allenporter, mind taking a look at this issue as it has been labeled with an integration (mcp_server) you are listed as a code owner for? Thanks!

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[allenporter]

I just updated the MCP server to support the new http streamable protocol in #153779 which hoping will help.

[kulawydzik]

oh thanks. Just to clarify, will this feature work immediately once merged, or will an example be added to the documentation first? And do you know which version it’s planned for?

[allenporter]

This will be in the next major release 2025.11.x since its a new feature. The documentation has been updated for the next release to, and the url now needs to point to/api/mcp which will use the new API.

[allenporter]

I have not fully tested with ChatGPT and Claude Remote yet as I don't currently have a dev server setup with an external URL, but that can be tested during beta.

[tecnobrat]

Do you know if that URL will be exposed automatically via HA Cloud?

[kulawydzik]

ChatGPT:

The server my.domain.here doesn't support RFC 7591 Dynamic Client Registration

version Core
2025.11.0b1

[venglov]

Same issue:

The server my.hostname doesn't support RFC 7591 Dynamic Client Registration

2025.11.0b3

[allenporter]

I believe what happens is that it attempts to connect to /.well-known/oauth-authorization-server on your server (you can go to that url for your home assistant and you get something like this:

{"authorization_endpoint":"https://example/auth/authorize","token_endpoint":"https://example/auth/token","revocation_endpoint":"https://example/auth/revoke","response_types_supported":["code"],"service_documentation":"https://developers.home-assistant.io/docs/auth_api","issuer":"https:/examples"}

I can't see how to enable this to try it out in Chat GPT -- i suspect its a paid service but let me know if i'm mistaken.

[keramblock]

Chatgpt on latest stable(2025.11.0):

Error fetching OAuth configuration
MCP server https://url.here does not implement OAuth

[keramblock]

I can't see how to enable this to try it out in Chat GPT -- i suspect its a paid service but let me know if i'm mistaken.

chatgpt.com itself is free, but I am not sure about mcp there.

Here is instruction: https://help.openai.com/en/articles/12584461-developer-mode-and-full-mcp-connectors-in-chatgpt-beta

[kulawydzik]

Chatgpt on latest stable(2025.11.0):

Error fetching OAuth configuration MCP server https://url.here does not implement OAuth

@keramblock you use /api/mcp?

@allenporter my /.well-known/oauth-authorization-server on 2025.11.0

{
  "authorization_endpoint": "https://my.domain.here/auth/authorize",
  "token_endpoint": "https://my.domain.here/auth/token",
  "revocation_endpoint": "https://my.domain.here/auth/revoke",
  "response_types_supported": ["code"],
  "service_documentation": "https://developers.home-assistant.io/docs/auth_api",
  "issuer": "https://my.domain.here"
}

I'm experiencing the same error as @keramblock on version core-2025.10.1 and old endpoint

Error fetching OAuth configuration
MCP server https://url.here/ does not implement OAuth

Now I'm getting a different error:

The server my.domain.here doesn't support RFC 7591 Dynamic Client Registration

[joshgetter]

I was able to get this setup with Claude Desktop via a connector with the latest 2025.11 update (using the /api/mcp URL rather than the previous /sse URL). The only thing was - rather than using the HA base URL for the OAuth Client ID, I had to use https://claude.ai/api/mcp/auth_callback for the client ID.