fix(mcp): drop minted JWT headers from catalog cache fingerprint

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

litellm/experimental_mcp_client/client.py

@@ -331,8 +331,8 @@ class MCPClient:
         if auth_value:
             self.update_auth_value(auth_value)
 
-    async def discovery_auth_fingerprint(self) -> str:
-        return self._hash_discovery_auth(await self.prepare_request_auth())
+    async def discovery_auth_fingerprint(self, *, ignore_headers: frozenset[str] = frozenset()) -> str:
+        return self._hash_discovery_auth(await self.prepare_request_auth(), ignore_headers)
 
     async def prepare_request_auth(self) -> httpx2.Request:
         """Preview the authenticated request without sending it, closing the auth flow afterwards."""
@@ -349,8 +349,11 @@ class MCPClient:
             await flow.aclose()
 
     @staticmethod
-    def _hash_discovery_auth(request: httpx2.Request) -> str:
-        material: Final = json.dumps((str(request.url), tuple(sorted(request.headers.multi_items()))))
+    def _hash_discovery_auth(request: httpx2.Request, ignore_headers: frozenset[str] = frozenset()) -> str:
+        kept: Final = tuple(
+            sorted(item for item in request.headers.multi_items() if item[0].lower() not in ignore_headers)
+        )
+        material: Final = json.dumps((str(request.url), kept))
         return hashlib.sha256(material.encode()).hexdigest()
 
     def _create_transport_context(

litellm/proxy/_experimental/mcp_server/mcp_server_manager.py

@@ -323,6 +323,7 @@ _OAuthDiscoveryOutcome: TypeAlias = _OAuthDiscoveryResolved | _OAuthDiscoveryFai
 class _ListHeaders:
     upstream: dict[str, str] | None
     signed_for_user: bool
+    minted: frozenset[str] = frozenset()
 
 
 @dataclass(frozen=True, slots=True)
@@ -4519,14 +4520,17 @@ class MCPServerManager:
         )
         if get_mcp_jwt_signer() is None or has_static_authorization or mcp_auth_header or has_extra_authorization:
             return _ListHeaders(headers, signed_for_user=False)
+        signed: Final = await inject_mcp_jwt_headers_for_upstream(
+            user_api_key_dict=user_api_key_auth,
+            extra_headers=headers,
+            raw_headers=raw_headers,
+            for_list_tools=True,
+        )
+        unsigned_items: Final = frozenset((headers or {}).items())
         return _ListHeaders(
-            await inject_mcp_jwt_headers_for_upstream(
-                user_api_key_dict=user_api_key_auth,
-                extra_headers=headers,
-                raw_headers=raw_headers,
-                for_list_tools=True,
-            ),
+            signed,
             signed_for_user=True,
+            minted=frozenset(name.lower() for name, value in signed.items() if (name, value) not in unsigned_items),
         )
 
     def _invalidate_discovery_lists(self, server_id: str) -> None:
@@ -4595,7 +4599,7 @@ class MCPServerManager:
                 subject_token=subject_token,
                 user_api_key_auth=user_api_key_auth,
             )
-            credential_fingerprint: Final = await client.discovery_auth_fingerprint()
+            credential_fingerprint: Final = await client.discovery_auth_fingerprint(ignore_headers=headers.minted)
             key: Final = self._discovery_key(
                 server,
                 user_api_key_auth,
@@ -4646,7 +4650,7 @@ class MCPServerManager:
                 subject_token=subject_token,
                 user_api_key_auth=user_api_key_auth,
             )
-            credential_fingerprint: Final = await client.discovery_auth_fingerprint()
+            credential_fingerprint: Final = await client.discovery_auth_fingerprint(ignore_headers=headers.minted)
             key: Final = self._discovery_key(
                 server,
                 user_api_key_auth,
@@ -4697,7 +4701,7 @@ class MCPServerManager:
                 subject_token=subject_token,
                 user_api_key_auth=user_api_key_auth,
             )
-            credential_fingerprint: Final = await client.discovery_auth_fingerprint()
+            credential_fingerprint: Final = await client.discovery_auth_fingerprint(ignore_headers=headers.minted)
             key: Final = self._discovery_key(
                 server,
                 user_api_key_auth,

tests/test_litellm/proxy/_experimental/mcp_server/test_mcp_server_manager.py

@@ -4098,6 +4098,7 @@ class TestMCPServerManager:
         from types import SimpleNamespace
 
         import litellm.proxy.guardrails.guardrail_hooks.mcp_jwt_signer.mcp_jwt_signer as jwt_signer_module
+        from litellm.experimental_mcp_client.client import MCPClient
         from litellm.proxy._types import UserAPIKeyAuth
         from litellm.proxy.guardrails.guardrail_hooks.mcp_jwt_signer.mcp_jwt_signer import MCPJWTSigner
 
@@ -4120,19 +4121,28 @@ class TestMCPServerManager:
             url="https://example.com",
             transport=MCPTransport.http,
         )
-        mock_client = AsyncMock()
-        setattr(mock_client, client_method, AsyncMock(side_effect=[[make_item("first")], [make_item("second")]]))
-        mock_client.discovery_auth_fingerprint = AsyncMock(return_value="test-credential-hash")
+        upstream_call = AsyncMock(side_effect=[[make_item("first")], [make_item("second")]])
+        seen_authorization: list[str] = []
+
+        async def create_client(**kwargs: object) -> MCPClient:
+            extra_headers = kwargs["extra_headers"]
+            assert isinstance(extra_headers, dict)
+            seen_authorization.append(extra_headers["Authorization"])
+            client = MCPClient(server_url=server.url, transport_type=MCPTransport.http, extra_headers=extra_headers)
+            setattr(client, client_method, upstream_call)
+            return client
+
         alice = UserAPIKeyAuth(api_key="sk-alice", user_id="alice")
         bob = UserAPIKeyAuth(api_key="sk-bob", user_id="bob")
 
-        with patch.object(manager, "_create_mcp_client", AsyncMock(return_value=mock_client)):
+        with patch.object(manager, "_create_mcp_client", AsyncMock(side_effect=create_client)):
             alice_first = await getattr(manager, manager_method)(server, user_api_key_auth=alice, add_prefix=False)
             alice_second = await getattr(manager, manager_method)(server, user_api_key_auth=alice, add_prefix=False)
             bob_first = await getattr(manager, manager_method)(server, user_api_key_auth=bob, add_prefix=False)
         assert [item.name for item in alice_first] == ["first"]
         assert alice_second == alice_first
         assert [item.name for item in bob_first] == ["second"]
+        assert len(seen_authorization) == 3 and len(set(seen_authorization)) == 3
 
     @pytest.mark.asyncio
     async def test_read_resource_from_server_success(self):