From 42821c102e487ca8e702eea6e2db9c3d0f76eeed Mon Sep 17 00:00:00 2001
From: Joshua Valluru <326636767+joshua-berri@users.noreply.github.com>
Date: Tue, 22 Sep 2026 13:47:10 -0700
Subject: [PATCH] fix(mcp): reconcile concurrent route changes when publishing
 catalog

---
 .../proxy/_experimental/mcp_server/catalog.py | 25 ++++++++++++---
 .../mcp_server/test_mcp_server_manager.py     | 32 +++++++++++++++++++
 2 files changed, 53 insertions(+), 4 deletions(-)

diff --git a/litellm/proxy/_experimental/mcp_server/catalog.py b/litellm/proxy/_experimental/mcp_server/catalog.py
index ed61b4360d9..f121ab08963 100644
--- a/litellm/proxy/_experimental/mcp_server/catalog.py
+++ b/litellm/proxy/_experimental/mcp_server/catalog.py
@@ -219,17 +219,34 @@ class TargetCatalog:
                 {key: value.model_copy(deep=True) for key, value in previous_config.items()}
             )
             await self.manager.hydrate_config_servers_dcr_clients(tuple(staged_config.values()))
-            staged_routing: Final = dict(self.manager.published_tool_routes)
+            initial_routing: Final = MappingProxyType(dict(self.manager.published_tool_routes))
+            staged_routing: Final = dict(initial_routing)
             closed: Final = asyncio.Event()
             routing_token: Final = self._staged_routing.set((staged_routing, closed))
             try:
                 with global_mcp_tool_registry.catalog_scope(global_mcp_tool_registry.published_tools) as staged_tools:
                     await self._reload()
                     concurrent_routes: Final = self._unchanged_routing(
-                        previous_servers, self.manager.published_tool_routes
+                        previous_servers,
+                        MappingProxyType(
+                            {
+                                name: owner
+                                for name, owner in self.manager.published_tool_routes.items()
+                                if initial_routing.get(name) != owner
+                                and staged_routing.get(name) == initial_routing.get(name)
+                            }
+                        ),
                     )
+                    removed_routes: Final = initial_routing.keys() - self.manager.published_tool_routes.keys()
                     retained_staged_routes: Final = self._unchanged_routing(
-                        previous_config | self.manager.registry, staged_routing
+                        previous_config | self.manager.registry,
+                        MappingProxyType(
+                            {
+                                name: owner
+                                for name, owner in staged_routing.items()
+                                if name not in removed_routes or owner != initial_routing[name]
+                            }
+                        ),
                     )
                     self.manager.config_mcp_servers = {
                         key: value.model_copy(
@@ -242,7 +259,7 @@ class TargetCatalog:
                         for key, value in self.manager.config_mcp_servers.items()
                     }
                     global_mcp_tool_registry.tools = staged_tools
-                    self.manager.published_tool_routes = concurrent_routes | retained_staged_routes
+                    self.manager.published_tool_routes = retained_staged_routes | concurrent_routes
             finally:
                 closed.set()
                 self._staged_routing.reset(routing_token)
diff --git a/tests/test_litellm/proxy/_experimental/mcp_server/test_mcp_server_manager.py b/tests/test_litellm/proxy/_experimental/mcp_server/test_mcp_server_manager.py
index fc70689b6c9..7462f948240 100644
--- a/tests/test_litellm/proxy/_experimental/mcp_server/test_mcp_server_manager.py
+++ b/tests/test_litellm/proxy/_experimental/mcp_server/test_mcp_server_manager.py
@@ -14605,6 +14605,38 @@ async def test_catalog_operation_retains_routes_only_for_same_configured_target(
     assert (tools[0].name in manager.published_tool_routes) is (change == "discovery")
 
 
+@pytest.mark.asyncio
+@pytest.mark.parametrize("change", ["concurrent", "staged", "deleted", "staged_after_delete", "staged_with_concurrent"])
+async def test_catalog_reload_keeps_new_route_owner_over_earlier_route(change):
+    manager: Final = MCPServerManager()
+    servers: Final = {name: MCPServer(server_id=name, name=name, transport=MCPTransport.http,
+        client_id="configured-client") for name in ("old_owner", "new_owner", "concurrent_owner")}
+    manager.config_mcp_servers = servers
+    manager.published_tool_routes = {"shared-search": "old_owner"}
+
+    async def read_rows(**_kwargs):
+        if change == "concurrent":
+            manager.published_tool_routes["shared-search"] = "new_owner"
+        elif change in ("staged", "staged_after_delete", "staged_with_concurrent"):
+            if change == "staged_after_delete":
+                manager.published_tool_routes.clear()
+            elif change == "staged_with_concurrent":
+                manager.published_tool_routes["shared-search"] = "concurrent_owner"
+            manager.tool_name_to_mcp_server_name_mapping["shared-search"] = "new_owner"
+        else:
+            manager.published_tool_routes.clear()
+        return []
+
+    prisma: Final = MagicMock()
+    prisma.db.litellm_mcpservertable.find_many = AsyncMock(side_effect=read_rows)
+    with patch("litellm.proxy.proxy_server.prisma_client", prisma):
+        await manager.reload_servers_from_database()
+    if change == "deleted":
+        assert "shared-search" not in manager.published_tool_routes
+    else:
+        assert manager.published_tool_routes["shared-search"] == "new_owner"
+
+
 @pytest.mark.asyncio
 async def test_catalog_observes_committed_update_and_delete_without_background_reload():
     from datetime import timedelta