From 69029c139e3efb4f750594bceb536d6ef944cbbb Mon Sep 17 00:00:00 2001 From: "devin-ai-integration[bot]" <158243242+devin-ai-integration[bot]@users.noreply.github.com> Date: Tue, 1 Sep 2026 17:48:01 -0700 Subject: [PATCH] fix(mcp): report per-server outcomes in aggregate REST tools/list (#39232) GET /mcp-rest/tools/list without server_id returned only the tools of the servers that answered and silently dropped any server whose listing failed (for example an OAuth-protected server without credentials), so clients could not tell a partial listing from a complete one. The aggregate response now carries a server_outcomes map keyed by server alias with the same classified outcome (ok/auth_required/forbidden/...) that the MCP protocol path already puts in _meta. Healthy tools and the HTTP 200 status are unchanged. Co-authored-by: yassin Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com> --- .../mcp_server/rest_endpoints.py | 71 +++++++++++-------- .../mcp_server/test_rest_endpoints.py | 11 ++- 2 files changed, 51 insertions(+), 31 deletions(-) diff --git a/litellm/proxy/_experimental/mcp_server/rest_endpoints.py b/litellm/proxy/_experimental/mcp_server/rest_endpoints.py index 2b89dba0e4f..d1ef73a15cd 100644 --- a/litellm/proxy/_experimental/mcp_server/rest_endpoints.py +++ b/litellm/proxy/_experimental/mcp_server/rest_endpoints.py @@ -1,7 +1,8 @@ import asyncio import importlib -from collections.abc import Awaitable, Callable, Mapping +from collections.abc import Awaitable, Callable, Mapping, Sequence from datetime import datetime +from types import MappingProxyType from typing import TYPE_CHECKING, Any, Final, Literal import anyio @@ -20,8 +21,11 @@ from litellm.proxy._experimental.mcp_server.exceptions import ( MCPUpstreamAuthError, ) from litellm.proxy._experimental.mcp_server.faults.list_outcomes import ( + ServerListOk, + ServerOutcome, classify_list_exception, list_fault_http_status, + outcome_wire_value, ) from litellm.proxy._experimental.mcp_server.ui_session_utils import ( acting_user_auth, @@ -99,6 +103,7 @@ if MCP_AVAILABLE: ListMCPToolsRestAPIResponseObject, MCPInfo, MCPServer, + _aggregate_server_key, # pyright: ignore[reportPrivateUsage] # same per-server key as the tools/list _meta outcomes _apply_toolset_scope, _fire_mcp_tool_call_logging, execute_mcp_tool, @@ -803,9 +808,6 @@ if MCP_AVAILABLE: list(allowed_server_ids_set), _rest_client_ip ) - list_tools_result: Final = [] - error_message = None - # If server_id is specified, only query that specific server if server_id: return await _list_tools_for_single_server( @@ -849,22 +851,19 @@ if MCP_AVAILABLE: else {} ) - # Query all servers the user has access to - errors: Final = [] - for allowed_server_id in allowed_server_ids: - server = global_mcp_server_manager.get_mcp_server_by_id(allowed_server_id) - if server is None: - continue - - server_auth_header = _get_server_auth_header(server, mcp_server_auth_headers, mcp_auth_header) - user_oauth_extra_headers = await _get_user_oauth_extra_headers( + async def list_server( + server: MCPServer, + ) -> tuple[Sequence[ListMCPToolsRestAPIResponseObject], ServerOutcome]: + server_auth_header: Final = _get_server_auth_header( + server, mcp_server_auth_headers, mcp_auth_header + ) + user_oauth_extra_headers: Final = await _get_user_oauth_extra_headers( server, user_api_key_dict, prefetched_creds=prefetched_oauth_creds, ) - try: - tools_result = await _get_tools_for_single_server( + tools_result: Final = await _get_tools_for_single_server( server, server_auth_header, raw_headers_from_request, @@ -872,24 +871,36 @@ if MCP_AVAILABLE: extra_headers=user_oauth_extra_headers, apply_tool_filters=apply_tool_filters, ) - list_tools_result.extend(tools_result) except Exception as e: verbose_logger.exception("Error getting tools from %s: %s", server.name, e) - errors.append( - f"{get_server_prefix(server)}: {classify_list_exception(e).tag}" - if isinstance(e, (MCPServerListError, MCPUpstreamAuthError)) - else f"{get_server_prefix(server)}: {e}" - ) - continue + return (), classify_list_exception(e) + return tools_result, ServerListOk(tool_count=len(tools_result)) - if errors and not list_tools_result: - error_message = "Failed to get tools from servers: " + "; ".join(errors) - - return { - "tools": list_tools_result, - "error": "partial_failure" if error_message else None, - "message": (error_message if error_message else "Successfully retrieved tools"), - } + # Query all servers the user has access to + queried_servers: Final = tuple( + server + for server in map(global_mcp_server_manager.get_mcp_server_by_id, allowed_server_ids) + if server is not None + ) + listings: Final = tuple([await list_server(server) for server in queried_servers]) + list_tools_result: Final = [tool for tools, _ in listings for tool in tools] + server_outcomes: Final = MappingProxyType( + {_aggregate_server_key(server): outcome for server, (_, outcome) in zip(queried_servers, listings)} + ) + errors: Final = tuple( + f"{key}: {outcome.tag}" for key, outcome in server_outcomes.items() if outcome.tag != "ok" + ) + error_message: Final = ( + "Failed to get tools from servers: " + "; ".join(errors) + if errors and not list_tools_result + else None + ) + return { + "tools": list_tools_result, + "error": "partial_failure" if error_message else None, + "message": (error_message if error_message else "Successfully retrieved tools"), + "server_outcomes": {key: outcome_wire_value(outcome) for key, outcome in server_outcomes.items()}, + } except MCPUpstreamAuthError as e: # Surface upstream pass-through 401/403 challenges to the client so diff --git a/tests/test_litellm/proxy/_experimental/mcp_server/test_rest_endpoints.py b/tests/test_litellm/proxy/_experimental/mcp_server/test_rest_endpoints.py index e36bef229f6..0480bbc40a7 100644 --- a/tests/test_litellm/proxy/_experimental/mcp_server/test_rest_endpoints.py +++ b/tests/test_litellm/proxy/_experimental/mcp_server/test_rest_endpoints.py @@ -1431,7 +1431,11 @@ class TestListToolsRestAPI: async def test_aggregate_list_absorbs_one_server_auth_failure(self, monkeypatch): """The multi-server aggregate listing degrades a server whose upstream rejects auth to an empty contribution and still returns the healthy - server's tools with a 200, rather than surfacing a 401.""" + server's tools with a 200, rather than surfacing a 401. The absorbed + server must still show up as a classified per-server outcome so a REST + caller can tell "needs upstream auth" apart from "has no tools".""" + from pydantic import TypeAdapter + from litellm.proxy._experimental.mcp_server.exceptions import ( MCPUpstreamAuthError, ) @@ -1497,6 +1501,11 @@ class TestListToolsRestAPI: assert result["tools"] == ["good-tool"] assert result["error"] is None + wire_body = json.loads(TypeAdapter(dict).dump_json(result)) + assert wire_body["server_outcomes"] == { + "good": {"status": "ok", "tool_count": 1}, + "bad": {"status": "auth_required", "http_status": 401}, + } async def test_name_resolution_finds_server_by_uuid(self, monkeypatch): """When server_id is a name string, it should be resolved to its UUID