fix(mcp): record OpenAPI tool definitions for pre-call guardrail metadata

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

litellm/proxy/_experimental/mcp_server/mcp_server_manager.py

@@ -4442,11 +4442,9 @@ class MCPServerManager:
                 # applied (e.g. "test_petstore-getinventory").  Do NOT pass them
                 # through _create_prefixed_tools — that would add the prefix a second
                 # time producing "test_petstore-test_petstore-getinventory".
-                if add_prefix:
-                    return tools
                 prefix: Final = get_server_prefix(server)
                 sep: Final = MCP_TOOL_PREFIX_SEPARATOR
-                return [  # mutable-ok: returned through the list[MCPTool] listing contract
+                unprefixed_tools: Final = [  # mutable-ok: returned through the list[MCPTool] listing contract
                     (
                         t.model_copy(update={"name": t.name[len(prefix) + len(sep) :]})
                         if t.name.startswith(f"{prefix}{sep}")
@@ -4454,6 +4452,10 @@ class MCPServerManager:
                     )
                     for t in tools
                 ]
+                self._listed_tools_by_server_id[server.server_id] = MappingProxyType(
+                    {t.name: t for t in unprefixed_tools}
+                )
+                return tools if add_prefix else unprefixed_tools
             else:
                 tools = await self._fetch_tools_with_timeout(client, server.name)
                 self._remember_upstream_initialize_instructions(server, client)

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

@@ -6632,6 +6632,40 @@ class TestMCPServerManager:
         listed = manager.get_listed_tool(server, "echo")
         assert listed is not None and listed.description == "shared"
 
+    @pytest.mark.asyncio
+    @pytest.mark.parametrize("add_prefix", [True, False])
+    async def test_openapi_listing_records_listed_tools(self, add_prefix):
+        from litellm.proxy._experimental.mcp_server.tool_registry import global_mcp_tool_registry
+
+        server = MCPServer(
+            server_id="petstore-id",
+            name="petstore",
+            alias="petstore",
+            transport=MCPTransport.http,
+            url=None,
+            spec_path="/spec.yaml",
+        )
+        manager = MCPServerManager()
+        manager._create_mcp_client = AsyncMock(return_value=AsyncMock())
+
+        async def _handler(**kwargs):
+            return None
+
+        with patch.dict(global_mcp_tool_registry.tools, {}, clear=True):
+            global_mcp_tool_registry.register_tool(
+                name="petstore-list_pets",
+                description="List pets",
+                input_schema={"type": "object", "properties": {"limit": {"type": "integer"}}},
+                handler=_handler,
+            )
+            listed = await manager._get_tools_from_server(server=server, add_prefix=add_prefix)
+
+        assert [t.name for t in listed] == ["petstore-list_pets" if add_prefix else "list_pets"]
+        for name in ("list_pets", "petstore-list_pets"):
+            tool = manager.get_listed_tool(server, name)
+            assert tool is not None and tool.description == "List pets"
+            assert tool.inputSchema["properties"] == {"limit": {"type": "integer"}}
+
     @pytest.mark.asyncio
     async def test_get_allowed_mcp_servers_with_user_api_key_auth(self):
         """