LibreChat client is not sending client_id when "token_endpoint" called.

[okohub]

I was playing with MCP Oauth flows for my simple MCP server, looks like there is a difference between behaviours of Claude Desktop App and LibreChat.

For example, when Claude Desktop App (of course with npx mcp-remote) calling my endpoint they are sending these parameters:

grant_type=authorization_code,
code=6f2f89a8-6931-4785-85ea-711e77683ee1,
code_verifier=3VPgVl6u0GxBePhMRlADsG1djjdlk0Gn90kLmv4ieDB,
redirect_uri=http://localhost:6082/oauth/callback,
resource=http://localhost:8999/
client_id=c24967e2-7077-4ebf-97ec-6b819e6d3e49,
client_secret=d8ce1419-1ce7-4f76-9164-a71f87b4c0f2,

When it turns to LibreChat (deployed at internal network), I saw these parameters:

grant_type=authorization_code,
code=33608bc9-d5b1-44c4-81fc-2bdbef0e9078,
code_verifier=Q7UufxwrW.HYfPgieGTgyICuO5F41119uXbdDQgPiwm,
redirect_uri=https://mymcp.com/oauth/callback,
resource=https://mymcp.com/

My expectation is; client_id should be sent to server when calling token_endpoint as in Claude flow.

(Then, may be client_secret should also be sent but I don't know whether it is a standard or not)

[dominic-mallo]

you must specify token_endpoint_auth_methods_supported: ["client_secret_post"] as per https://www.librechat.ai/docs/configuration/librechat_yaml/object_structure/mcp_servers#oauth