Protected Resource Metadata resource erroneous when setting up authentication on server

Initial Checks

• I confirm that I'm using the latest version of MCP Python SDK
• I confirm that I searched for my issue in https://github.com/modelcontextprotocol/python-sdk/issues before opening this issue

Description

I am getting the following error when I try to enable MCP server authentication and configure it in VSCODE copilot:

Error Error sending message to http://localhost:8000/mcp: Error: Protected Resource Metadata resource "http://localhost:8000/" does not match MCP server resolved resource "http://localhost:8000/mcp". The MCP server must follow OAuth spec https://datatracker.ietf.org/doc/html/rfc9728#PRConfigurationValidation

From what I have seen, the error is caused because the metada that is returned in the endpoint "/.well-known/oauth-protected-resource" in the resource field does not match the url of the MCP server to be configured to use copilot and what is specified in the definition if they should match. You can see here https://datatracker.ietf.org/doc/html/rfc9728#PRConfigurationValidation

I have made a small snippet of code available here https://github.com/carlosemart/python-mcp-oauth-example in which you can see that the well-know answer is:

{
    "resource": "http://localhost:8000/",
    "authorization_servers": [
        "https://auth.example.com/"
    ],
    "scopes_supported": [
        "user"
    ],
    "bearer_methods_supported": [
        "header"
    ]
}

and in the resource field you should see "http://localhost:8000/mcp" which is the url that is configured in VSCODE.

Example Code

from mcp.server.auth.provider import AccessToken, TokenVerifier
from mcp.server.auth.settings import AuthSettings
from mcp.server.fastmcp import FastMCP
from pydantic import AnyHttpUrl


class SimpleTokenVerifier(TokenVerifier):
    """Simple token verifier for demonstration."""

    async def verify_token(self, token: str) -> AccessToken | None:
        return AccessToken(
            token=token,
            scopes=["user"],
        )


# Create an MCP server
mcp = FastMCP(
    "Demo",
    stateless_http=True,
    # Token verifier for authentication
    token_verifier=SimpleTokenVerifier(),
    # Auth settings for RFC 9728 Protected Resource Metadata
    auth=AuthSettings(
        issuer_url=AnyHttpUrl("https://auth.example.com"),  # Authorization Server URL
        resource_server_url=AnyHttpUrl("http://localhost:8000"),  # This server's URL
        required_scopes=["user"],
    ),
)


# Add an addition tool
@mcp.tool()
def add(a: int, b: int) -> int:
    """Add two numbers"""
    return a + b


# Add a dynamic greeting resource
@mcp.resource("greeting://{name}")
def get_greeting(name: str) -> str:
    """Get a personalized greeting"""
    return f"Hello, {name}!"


# Add a prompt
@mcp.prompt()
def greet_user(name: str, style: str = "friendly") -> str:
    """Generate a greeting prompt"""
    styles = {
        "friendly": "Please write a warm, friendly greeting",
        "formal": "Please write a formal, professional greeting",
        "casual": "Please write a casual, relaxed greeting",
    }

    return f"{styles.get(style, styles['friendly'])} for someone named {name}."


def main():
    """Entry point for the direct execution server."""
    mcp.run(transport="streamable-http")


if __name__ == "__main__":
    main()

Python & MCP Python SDK

Tested with python version 3.11.9 and 3.12.5, and MCP Python SDK 1.12.4 version

從 AuthSettings 和 issue 中描述的受保護資源中繼資料端點開始，然後使用提供的 Python 範例和 streamable-HTTP 伺服器重現該行為。比較已設定的 MCP URL 與中繼資料中的資源值，並參考 RFC 9728 的驗證要求。當中繼資料回報已設定的 /mcp 資源，且驗證設定不再觸發不相符錯誤時，即表示完成。