fix(mcp): retain discovered routes across cached catalog operations

litellm/proxy/_experimental/mcp_server/catalog.py

@@ -167,10 +167,11 @@ class TargetCatalog:
         from litellm.proxy._experimental.mcp_server.tool_registry import global_mcp_tool_registry
 
         shared: Final = await self._fresh_snapshot()
+        initial_routing: Final = self._unchanged_routing(shared.servers, self.manager.published_tool_routes)
         snapshot: Final = replace(
             shared,
             servers=MappingProxyType({key: value.model_copy(deep=True) for key, value in shared.servers.items()}),
-            routing=dict(shared.routing),
+            routing=dict(initial_routing),
         )
         closed: Final = asyncio.Event()
         token: Final = self._operation.set((snapshot, closed))
@@ -180,11 +181,12 @@ class TargetCatalog:
         finally:
             closed.set()
             self._operation.reset(token)
-            self._retain_discovered_routing(snapshot)
+            self._retain_discovered_routing(snapshot, initial_routing)
 
-    def _retain_discovered_routing(self, snapshot: CatalogSnapshot) -> None:
+    def _retain_discovered_routing(self, snapshot: CatalogSnapshot, initial_routing: Mapping[str, str]) -> None:
         self.manager.published_tool_routes = self.manager.published_tool_routes | self._unchanged_routing(
-            snapshot.servers, snapshot.routing
+            snapshot.servers,
+            {name: owner for name, owner in snapshot.routing.items() if initial_routing.get(name) != owner},
         )
 
     def _unchanged_routing(

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

@@ -16990,3 +16990,44 @@ async def test_upstream_preparation_honors_case_sensitive_extra_command(monkeypa
     client: Final = await MCPServerManager()._create_mcp_client(server)
     assert client.stdio_config is not None
     assert client.stdio_config["command"] == "/opt/tools/CustomRunner"
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize("overlap", [False, True])
+async def test_catalog_cached_revision_retains_newly_discovered_tool_routes(monkeypatch, overlap):
+    from mcp.types import Tool
+
+    read_rows = AsyncMock(return_value=[])
+    _catalog_database(monkeypatch, read_rows, AsyncMock(return_value=_revision_row(7)))
+    manager = MCPServerManager()
+    first = MCPServer(server_id="first", name="first", transport=MCPTransport.http)
+    second = MCPServer(server_id="second", name="second", transport=MCPTransport.http)
+    manager.config_mcp_servers = {server.server_id: server for server in (first, second)}
+    manager.published_tool_routes = {"search": "first"}
+    ready = asyncio.Event()
+    release = asyncio.Event()
+
+    async def read_catalog():
+        async with manager.catalog.operation():
+            assert manager._get_mcp_server_from_tool_name("search").server_id == "first"
+            ready.set()
+            await release.wait()
+
+    reader = asyncio.create_task(read_catalog()) if overlap else None
+    try:
+        if reader is not None:
+            await asyncio.wait_for(ready.wait(), 2)
+        async with manager.catalog.operation():
+            manager._create_prefixed_tools([Tool(name="search", input_schema={})], second)
+        assert manager.published_tool_routes["search"] == "second"
+        release.set()
+        if reader is not None:
+            await asyncio.wait_for(reader, 2)
+        async with manager.catalog.operation():
+            assert manager._get_mcp_server_from_tool_name("search").server_id == "second"
+        assert manager.published_tool_routes["search"] == "second"
+        read_rows.assert_awaited_once()
+    finally:
+        if reader is not None:
+            reader.cancel()
+            await asyncio.gather(reader, return_exceptions=True)

tests/unit/proxy/_experimental/mcp_server/test_mcp_server_tool_calls_and_headers.py

@@ -7735,8 +7735,8 @@ async def test_execute_mcp_tool_rest_server_id_injects_requested_server_credenti
         ),
         patch.object(
             mcp_operations.global_mcp_server_manager,
-            "get_registry",
-            return_value={
+            "registry",
+            {
                 requested_server.server_id: requested_server,
                 collision_server.server_id: collision_server,
             },