fix(mcp): keep DeepSeek tool cleanup and the guardrail policy result on lts/1.108.x

DeepSeek now sends the params through its own tool cleanup when a hosted MCP
tool is dropped, so a tool_choice naming that tool and the tool selection params
beside legacy functions are cleared as the line does today.

The MCP security guardrail uses the gateway's saved toolset check, so a failed
read reports the name as unregistered with the policy result instead of raising.

Also fixes three lint errors the line already has, two import orders and one
duplicate test import, since make check cannot pass on this line without them.

litellm/llms/deepseek/chat/transformation.py

@@ -42,9 +42,14 @@ class DeepSeekChatConfig(OpenAIGPTConfig):
 
         Reference: https://api-docs.deepseek.com/guides/thinking_mode
         """
+        params_without_hosted_mcp: Final = tool_params_without_hosted_mcp(
+            non_default_params, model=model, route="deepseek", drop_params=drop_params
+        )
         # Let parent handle standard params first
         optional_params = super().map_openai_params(
-            tool_params_without_hosted_mcp(non_default_params, model=model, route="deepseek", drop_params=drop_params),
+            params_without_hosted_mcp
+            if params_without_hosted_mcp is non_default_params
+            else self._drop_unsupported_tools(non_default_params),
             optional_params,
             model,
             drop_params,

litellm/proxy/db/db_transaction_queue/redis_update_buffer.py

@@ -13,7 +13,6 @@ from itertools import chain
 from typing import TYPE_CHECKING, Any, Final, Literal, TypeAlias, TypeVar, cast
 
 from pydantic import TypeAdapter
-
 from redis.exceptions import RedisError
 
 from litellm._internal_context import with_service_target

litellm/proxy/guardrails/guardrail_hooks/mcp_security/mcp_security_guardrail.py

@@ -18,6 +18,7 @@ from litellm.integrations.custom_guardrail import (
 from litellm.proxy._types import UserAPIKeyAuth
 from litellm.responses.mcp.litellm_proxy_mcp_handler import (
     LITELLM_PROXY_MCP_SERVER_URL_PREFIX,
+    saved_toolset_exists,
 )
 from litellm.types.guardrails import GuardrailEventHooks
 
@@ -104,7 +105,6 @@ class MCPSecurityGuardrail(CustomGuardrail):
         from litellm.proxy._experimental.mcp_server.mcp_server_manager import (
             global_mcp_server_manager,
         )
-        from litellm.proxy.proxy_server import prisma_client
 
         async with global_mcp_server_manager.catalog.operation():
             not_servers: Final = frozenset(
@@ -112,12 +112,4 @@ class MCPSecurityGuardrail(CustomGuardrail):
                 for name in requested_servers
                 if global_mcp_server_manager.get_mcp_server_by_identifier(name) is None
             )
-            if prisma_client is None:
-                return not_servers
-            return frozenset(
-                [
-                    name
-                    for name in not_servers
-                    if await global_mcp_server_manager.get_toolset_by_name_cached(prisma_client, name) is None
-                ]
-            )
+            return frozenset([name for name in not_servers if not await saved_toolset_exists(name)])

litellm/responses/mcp/litellm_proxy_mcp_handler.py

@@ -105,7 +105,7 @@ def _registry_serves(name: str, servers: Collection[MCPServer]) -> bool:
     )
 
 
-async def _toolset_exists(name: str) -> bool:
+async def saved_toolset_exists(name: str) -> bool:
     try:
         from litellm.proxy._experimental.mcp_server.mcp_server_manager import (
             global_mcp_server_manager,
@@ -124,7 +124,7 @@ async def _toolset_exists(name: str) -> bool:
 async def _gateway_served_names(
     names: Collection[str],
     servers: Callable[[], Collection[MCPServer]] = _registered_mcp_servers,
-    toolset_exists: Callable[[str], Awaitable[bool]] = _toolset_exists,
+    toolset_exists: Callable[[str], Awaitable[bool]] = saved_toolset_exists,
 ) -> frozenset[str]:
     registered: Final = tuple(servers()) if names else ()
     return frozenset([name for name in names if _registry_serves(name, registered) or await toolset_exists(name)])

litellm/utils.py

@@ -438,11 +438,11 @@ if TYPE_CHECKING:
     )
     from litellm.llms.cohere.common_utils import CohereModelInfo
     from litellm.llms.custom_httpx.http_handler import AsyncHTTPHandler, HTTPHandler
+    from litellm.llms.custom_llm import CustomLLM
     from litellm.router_utils.get_retry_from_policy import (
         get_num_retries_from_retry_policy,
         reset_retry_policy,
     )
-    from litellm.llms.custom_llm import CustomLLM
     from litellm.types.llms.anthropic import (
         ANTHROPIC_API_ONLY_HEADERS,
         AnthropicThinkingParam,

tests/unit/litellm_core_utils/test_streaming_chunk_builder_utils.py

@@ -18,7 +18,6 @@ from litellm.types.utils import (
     ChatCompletionMessageToolCall,
     Delta,
     Function,
-    GenericStreamingChunk,
     ModelResponseStream,
     PromptTokensDetails,
     ServerToolUse,

tests/unit/llms/deepseek/chat/test_deepseek_chat_transformation.py

@@ -952,3 +952,33 @@ def test_deepseek_sends_no_tools_when_drop_params_drops_every_hosted_mcp_tool(mo
     assert "tools" not in result
     assert "tool_choice" not in result
     assert "parallel_tool_calls" not in result
+
+
+def test_deepseek_clears_a_tool_choice_naming_the_hosted_mcp_tool_drop_params_dropped(monkeypatch):
+    monkeypatch.setattr(litellm, "drop_params", False)
+    result: Final = DeepSeekChatConfig().map_openai_params(
+        {
+            "tools": [_HOSTED_MCP_TOOL, _function_tool("shell")],
+            "tool_choice": {"type": "function", "function": {"name": "deepwiki"}},
+        },
+        {},
+        "deepseek-v4-flash",
+        True,
+    )
+    assert result["tools"] == [_function_tool("shell")]
+    assert "tool_choice" not in result
+
+
+def test_deepseek_removes_tool_selection_beside_legacy_functions_when_drop_params_drops_every_tool(monkeypatch):
+    monkeypatch.setattr(litellm, "drop_params", False)
+    functions: Final = [{"name": "shell", "parameters": {"type": "object", "properties": {}}}]
+    result: Final = DeepSeekChatConfig().map_openai_params(
+        {"tools": [_HOSTED_MCP_TOOL], "functions": functions, "tool_choice": "required", "parallel_tool_calls": True},
+        {},
+        "deepseek-v4-flash",
+        True,
+    )
+    assert result["functions"] == functions
+    assert "tools" not in result
+    assert "tool_choice" not in result
+    assert "parallel_tool_calls" not in result

tests/unit/proxy/guardrails/guardrail_hooks/test_mcp_security.py

@@ -255,3 +255,30 @@ async def test_allows_saved_toolset_by_name_and_blocks_unknown_name(guardrail, c
     ):
         await guardrail.async_pre_call_hook(UserAPIKeyAuth(), MagicMock(), data, call_type)
     assert exc.value.detail["unregistered_servers"] == ["evil_server"]
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize("call_type", ["acompletion", "aresponses"])
+async def test_blocks_the_name_with_the_policy_result_when_the_toolset_read_fails(guardrail, call_type):
+    prisma: Final = MagicMock()
+    prisma.writer_db = prisma.db
+    prisma.db.litellm_mcpservertable.find_many = AsyncMock(return_value=[])
+    prisma.db.litellm_config.find_unique = AsyncMock(return_value=None)
+    prisma.db.litellm_mcptoolsettable.find_first = AsyncMock(side_effect=RuntimeError("toolset table unavailable"))
+    data: Final = {
+        "tools": [{"type": "mcp", "server_url": "litellm_proxy/mcp/research"}],
+        "guardrails": ["test-mcp-security"],
+    }
+    with (
+        patch("litellm.proxy.proxy_server.prisma_client", prisma),
+        patch("litellm.proxy.proxy_server.general_settings", {}),
+        patch("litellm.proxy.proxy_server.user_api_key_cache", DualCache()),
+        patch(
+            "litellm.proxy._experimental.mcp_server.mcp_server_manager.global_mcp_server_manager",
+            MCPServerManager(),
+        ),
+        pytest.raises(HTTPException) as exc,
+    ):
+        await guardrail.async_pre_call_hook(UserAPIKeyAuth(), MagicMock(), data, call_type)
+    assert exc.value.status_code == 400
+    assert exc.value.detail["unregistered_servers"] == ["research"]