Keep the missing-issuer warning text static

The warning is already attributed to the caller's constructor line, so it does not need the provider name or server URL; _checked_issuer keeps its single argument.

Author: maxisbey

src/mcp/client/auth/extensions/client_credentials.py

@@ -23,12 +23,11 @@
 from mcp.shared.auth import OAuthClientInformationFull, OAuthClientMetadata
 
 
-def _checked_issuer(issuer: str | None, provider: str, server_url: str) -> str | None:
+def _checked_issuer(issuer: str | None) -> str | None:
     if issuer is None:
         warnings.warn(
-            f"{provider} created without `issuer`: the client credentials will be sent to whichever "
-            f"authorization server {server_url} advertises. Pass issuer=<the issuer URL your authorization "
-            "server's metadata reports> so that token requests are only ever built for that server.",
+            "No `issuer` given: client credentials will be sent to whichever authorization server the MCP "
+            "server advertises. Pass issuer=<your authorization server's issuer URL> to send them only there.",
             stacklevel=3,
         )
         return None
@@ -117,7 +116,7 @@ def __init__(
             scope=scope,
         )
         super().__init__(server_url, client_metadata, storage, None, None)
-        self._issuer = _checked_issuer(issuer, type(self).__name__, server_url)
+        self._issuer = _checked_issuer(issuer)
         # Store client_info to be set during _initialize - no dynamic registration needed
         self._fixed_client_info = OAuthClientInformationFull(
             redirect_uris=None,
@@ -348,7 +347,7 @@ def __init__(
         )
         super().__init__(server_url, client_metadata, storage, None, None)
         self._assertion_provider = assertion_provider
-        self._issuer = _checked_issuer(issuer, type(self).__name__, server_url)
+        self._issuer = _checked_issuer(issuer)
         # Store client_info to be set during _initialize - no dynamic registration needed
         self._fixed_client_info = OAuthClientInformationFull(
             redirect_uris=None,

tests/client/auth/extensions/test_client_credentials.py

@@ -467,11 +467,9 @@ async def assertion_provider(audience: str) -> str:
 
     [warning] = recorded
     assert warning.filename == __file__
-    provider = "ClientCredentialsOAuthProvider" if kind == "secret" else "PrivateKeyJWTOAuthProvider"
     assert str(warning.message) == (
-        f"{provider} created without `issuer`: the client credentials will be sent to whichever "
-        "authorization server https://api.example.com/v1/mcp advertises. Pass issuer=<the issuer URL your "
-        "authorization server's metadata reports> so that token requests are only ever built for that server."
+        "No `issuer` given: client credentials will be sent to whichever authorization server the MCP "
+        "server advertises. Pass issuer=<your authorization server's issuer URL> to send them only there."
     )
 
 
@@ -486,7 +484,7 @@ async def test_without_issuer_the_exchange_follows_whichever_server_was_discover
     async def assertion_provider(audience: str) -> str:
         return "jwt"
 
-    with pytest.warns(UserWarning, match="created without `issuer`"):
+    with pytest.warns(UserWarning, match="No `issuer` given"):
         if kind == "secret":
             provider: OAuthClientProvider = ClientCredentialsOAuthProvider(
                 server_url=_SERVER_URL, storage=mock_storage, client_id="c", client_secret="s"