mcp oauth (experimental) not working with supabase mcp

What version of Codex is running?

codex-cli 0.45.0

What subscription do you have?

API

Which model were you using?

gpt-5-codex

What platform is your computer?

Darwin 24.6.0 x86_64 i386

What issue are you seeing?

experimental_use_rmcp_client = true
[mcp_servers.supabase]
url = "https://mcp.supabase.com/mcp?project_ref=xxxxxxxxxx&read_only=true"

❯ codex mcp login supabase
Dynamic registration failed: Registration failed: HTTP 404 Not Found: 
Authorize `supabase` by opening this URL in your browser:
https://mcp.supabase.com/authorize?project_ref=xxxxxxxxx&read_only=true&response_type=code&client_id=mcp-client&state=tshk3Txx-eZzGANecv2EaJZDQ&code_challenge=xxxxxx&code_challenge_method=S256&redirect_uri=http%3A%2F%2F127.0.0.1%3A49387%2Fcallback

I open the link and says not found, supabase provides buttons for vscode that use the same link and it works.

What steps can reproduce the bug?

open a supabase account, create a poject, try to connect via mcp with codex.

What is the expected behavior?

_No response_

Additional information

_No response_