From 2e82799d7d27543f3453df1977f226b213496741 Mon Sep 17 00:00:00 2001
From: Frank Deng <dengjia@gmail.com>
Date: Mon, 28 Sep 2026 14:03:49 -0700
Subject: [PATCH] fix(mcp): use top-level description when nested value is null

---
 .../mcp_server/mcp_server_manager.py          |  4 +--
 .../mcp_server/test_mcp_custom_fields.py      | 34 +++++++++++++------
 2 files changed, 25 insertions(+), 13 deletions(-)

diff --git a/litellm/proxy/_experimental/mcp_server/mcp_server_manager.py b/litellm/proxy/_experimental/mcp_server/mcp_server_manager.py
index ea685c431bd..af5d8849888 100644
--- a/litellm/proxy/_experimental/mcp_server/mcp_server_manager.py
+++ b/litellm/proxy/_experimental/mcp_server/mcp_server_manager.py
@@ -2407,7 +2407,7 @@ class MCPServerManager:
             # Set default values for core fields if not present
             if "server_name" not in mcp_info:
                 mcp_info["server_name"] = server_name
-            if "description" not in mcp_info and server_config.get("description"):
+            if mcp_info.get("description") is None and server_config.get("description"):
                 mcp_info["description"] = server_config.get("description")
             _normalize_mcp_server_cost_info(mcp_info)
 
@@ -3095,7 +3095,7 @@ class MCPServerManager:
         mcp_info: Final[MCPInfo] = _mcp_info.copy()
         if "server_name" not in mcp_info:
             mcp_info["server_name"] = mcp_server.server_name or mcp_server.server_id
-        if "description" not in mcp_info and mcp_server.description:
+        if mcp_info.get("description") is None and mcp_server.description:
             mcp_info["description"] = mcp_server.description
         _normalize_mcp_server_cost_info(mcp_info)
 
diff --git a/tests/test_litellm/proxy/_experimental/mcp_server/test_mcp_custom_fields.py b/tests/test_litellm/proxy/_experimental/mcp_server/test_mcp_custom_fields.py
index e3437bf16f6..5914da78dec 100644
--- a/tests/test_litellm/proxy/_experimental/mcp_server/test_mcp_custom_fields.py
+++ b/tests/test_litellm/proxy/_experimental/mcp_server/test_mcp_custom_fields.py
@@ -4,15 +4,8 @@ Test suite for MCP server custom fields functionality.
 Tests that mcp_info can accept arbitrary custom fields in addition to predefined ones.
 """
 
-import pytest
-from unittest.mock import Mock, patch
-from typing import Dict, Any
-
-# Add the path to find the modules
-
-from litellm.proxy._experimental.mcp_server.mcp_server_manager import MCPServerManager
-from litellm.types.mcp import MCPAuth
 from litellm.proxy._types import LiteLLM_MCPServerTable
+from litellm.types.mcp import MCPAuth
 
 
 class TestMCPCustomFields:
@@ -106,6 +99,26 @@ class TestMCPCustomFields:
         assert mcp_info["metadata"] == {"source": "database"}
         assert mcp_info["version"] == "1.0.0"
 
+    async def test_updated_description_is_listed_when_mcp_info_description_is_null(
+        self, config_only_mcp_manager_factory
+    ):
+        manager = config_only_mcp_manager_factory()
+        server = LiteLLM_MCPServerTable(
+            server_id="test-server-id",
+            server_name="Test Server",
+            description=None,
+            url="http://localhost:3000",
+            transport="http",
+            auth_type=MCPAuth.none,
+            mcp_info={"server_name": "Test Server", "description": None},
+        )
+
+        await manager.add_server(server)
+        await manager.update_server(server.model_copy(update={"description": "Updated description"}))
+
+        listed_servers = await manager.get_all_mcp_servers_unfiltered()
+        assert listed_servers[0].description == "Updated description"
+
     async def test_empty_mcp_info_handled_gracefully(self, config_only_mcp_manager_factory):
         """Test that empty or missing mcp_info is handled gracefully."""
         manager = config_only_mcp_manager_factory()
@@ -155,17 +168,16 @@ class TestMCPCustomFields:
         assert mcp_info["server_name"] == "test_server"
         assert mcp_info["description"] == "Server description"
 
-    async def test_config_description_fallback(self, config_only_mcp_manager_factory):
+    async def test_config_description_fallback_when_mcp_info_description_is_null(self, config_only_mcp_manager_factory):
         """Test that description from config level is used as fallback."""
         manager = config_only_mcp_manager_factory()
 
-        # Config with description at server level but not in mcp_info
         mock_config = {
             "test_server": {
                 "url": "http://localhost:3000",
                 "transport": "http",
                 "description": "Config level description",
-                "mcp_info": {"custom_field": "custom_value"},
+                "mcp_info": {"description": None, "custom_field": "custom_value"},
             }
         }