Don't use client_credentials by default; fix test

Author: LucaButBoring

src/mcp/shared/auth.py

@@ -47,7 +47,6 @@ class OAuthClientMetadata(BaseModel):
     # supported grant_types of this implementation
     grant_types: list[Literal["authorization_code", "client_credentials", "refresh_token"]] = [
         "authorization_code",
-        "client_credentials",
         "refresh_token",
     ]
     # this implementation only supports code; ie: it does not support implicit grants

tests/client/test_auth.py

@@ -246,7 +246,7 @@ async def test_token_exchange_request(self, oauth_provider):
             redirect_uris=[AnyUrl("http://localhost:3030/callback")],
         )
 
-        request = await oauth_provider._exchange_token("test_auth_code", "test_verifier")
+        request = await oauth_provider._exchange_token_authorization_code("test_auth_code", "test_verifier")
 
         assert request.method == "POST"
         assert str(request.url) == "https://api.example.com/token"