fix(hosted_vllm): forward strict only when true and leave the Responses bridge and MCP tools unchanged

This commit is contained in:
mateo-berri 2026-10-28 18:58:22 -07:00
parent 3c629ce7c3
commit 4b59c5a240
6 changed files with 48 additions and 43 deletions

View file

@ -3,9 +3,11 @@ Translate from OpenAI's `/v1/chat/completions` to VLLM's `/v1/chat/completions`
"""
import json
from collections.abc import Coroutine
from collections.abc import Coroutine, Mapping
from typing import Final, Literal, cast, overload
from typing_extensions import TypeIs # noqa: TID251 # TypeIs reaches typing only on 3.13
from litellm.litellm_core_utils.prompt_templates.common_utils import (
get_image_mime_type_from_url,
)
@ -26,6 +28,17 @@ from litellm.types.llms.openai import (
from ...openai.chat.gpt_transformation import OpenAIGPTConfig
def _is_str_keyed_mapping(value: object) -> TypeIs[Mapping[str, object]]: # guard-ok: JSON tool objects have str keys
return isinstance(value, Mapping)
def _strict_only_when_true(tool: Mapping[str, object]) -> Mapping[str, object]:
function: Final = tool.get("function")
if not _is_str_keyed_mapping(function) or function.get("strict", True) is True:
return tool
return {**tool, "function": {key: value for key, value in function.items() if key != "strict"}}
class HostedVLLMChatConfig(OpenAIGPTConfig):
def _convert_custom_tools_to_function_tools(self, tools: list[dict[str, object]]) -> list[dict[str, object]]:
"""
@ -88,7 +101,9 @@ class HostedVLLMChatConfig(OpenAIGPTConfig):
tools: Final = non_default_params.pop("tools", None)
if tools is not None:
non_default_params["tools"] = (
self._convert_custom_tools_to_function_tools(tools) if isinstance(tools, list) else tools
[_strict_only_when_true(tool) for tool in self._convert_custom_tools_to_function_tools(tools)]
if isinstance(tools, list)
else tools
)
thinking: Final = non_default_params.pop("thinking", None)

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@ -37,6 +37,7 @@ def transform_mcp_tool_to_openai_tool(mcp_tool: MCPTool) -> ChatCompletionToolPa
name=mcp_tool.name,
description=mcp_tool.description or "",
parameters=normalized_parameters,
strict=False,
),
)

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@ -2708,7 +2708,7 @@ class LiteLLMCompletionResponsesConfig:
return convert_custom_tool_to_function_tool({**namespace_tool, "description": description})
raw_parameters: Final = namespace_tool.get("parameters")
parameters: Final[Mapping[str, object]] = (
parameters: Final = (
MappingProxyType(raw_parameters) if isinstance(raw_parameters, Mapping) else MappingProxyType({})
)
normalized_parameters: Final = (
@ -2716,16 +2716,11 @@ class LiteLLMCompletionResponsesConfig:
)
tool_name: Final = str(namespace_tool.get("name") or "")
chat_tool_name: Final = f"{namespace}__{tool_name}" if nested else tool_name
chat_parameters: Final = dict(normalized_parameters)
caller_strict: Final = namespace_tool.get("strict")
function: Final = (
ChatCompletionToolParamFunctionChunk(
name=chat_tool_name, description=description, parameters=chat_parameters, strict=caller_strict
)
if isinstance(caller_strict, bool)
else ChatCompletionToolParamFunctionChunk(
name=chat_tool_name, description=description, parameters=chat_parameters
)
function: Final = ChatCompletionToolParamFunctionChunk(
name=chat_tool_name,
description=description,
parameters=dict(normalized_parameters),
strict=bool(namespace_tool.get("strict", False)),
)
return function_chat_tool(
function,
@ -2803,14 +2798,13 @@ class LiteLLMCompletionResponsesConfig:
typed_tool: Final = cast(FunctionToolParam, tool)
raw_parameters: Final = typed_tool.get("parameters", {}) or {}
parameters: Final = {**raw_parameters} if "type" in raw_parameters else {**raw_parameters, "type": "object"}
caller_strict: Final = typed_tool.get("strict")
chat_completion_tool: Final[dict[str, object]] = {
"type": "function",
"function": {
"name": typed_tool.get("name") or "",
"description": typed_tool.get("description") or "",
"parameters": parameters,
**({"strict": caller_strict} if isinstance(caller_strict, bool) else {}),
"strict": typed_tool.get("strict", False) or False,
},
}
if tool.get("cache_control"):

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@ -402,7 +402,7 @@ def test_hosted_vllm_custom_tools_use_top_level_input_schema():
assert tools[0]["function"]["parameters"] == input_schema
def _strict_tools(strict: bool = True) -> list[dict[str, object]]:
def _strict_tools(strict: object = True) -> list[dict[str, object]]:
return [
{
"type": "function",
@ -428,10 +428,9 @@ def _strict_tools(strict: bool = True) -> list[dict[str, object]]:
]
@pytest.mark.parametrize("strict", [True, False])
@pytest.mark.parametrize("drop_params", [True, False])
def test_hosted_vllm_forwards_strict_tool_schema_as_sent(drop_params: bool, strict: bool) -> None:
tools: Final = _strict_tools(strict)
def test_hosted_vllm_forwards_strict_tool_schema_as_sent(drop_params: bool) -> None:
tools: Final = _strict_tools()
sent: Final = copy.deepcopy(tools)
optional_params: Final = get_optional_params(
@ -446,6 +445,26 @@ def test_hosted_vllm_forwards_strict_tool_schema_as_sent(drop_params: bool, stri
assert tools == sent
@pytest.mark.parametrize("unmarked_strict", [False, None, "true", 1])
def test_hosted_vllm_drops_a_strict_that_is_not_true(unmarked_strict: object) -> None:
tools: Final = [*_strict_tools(), *_strict_tools(unmarked_strict)]
sent: Final = copy.deepcopy(tools)
optional_params: Final = get_optional_params(
model="my-vllm-model",
custom_llm_provider="hosted_vllm",
tools=tools,
tool_choice="required",
)
strict_tool, unmarked_tool = _strict_tools()[0], _strict_tools(unmarked_strict)[0]
assert optional_params["tools"] == [
strict_tool,
{**unmarked_tool, "function": {k: v for k, v in unmarked_tool["function"].items() if k != "strict"}},
]
assert tools == sent
def test_hosted_vllm_additional_drop_params_removes_only_the_named_tool_fields() -> None:
tools: Final = _strict_tools()
sent: Final = copy.deepcopy(tools)

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@ -73,7 +73,6 @@ def test_transform_mcp_tool_to_openai_tool(mock_mcp_tool):
"properties": {"test": {"type": "string"}},
"additionalProperties": False,
}
assert "strict" not in openai_tool["function"]
def testtransform_openai_tool_call_request_to_mcp_tool_call_request(mock_mcp_tool):

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@ -2001,29 +2001,6 @@ class TestToolTransformation:
assert [tool["function"]["name"] for tool in not_deferred] == ["finance__get_stock_price", "get_weather"]
assert all("defer_loading" not in tool for tool in not_deferred)
def test_function_tools_carry_strict_only_when_the_caller_set_it(self) -> None:
strict_variants: Final = {"unset": {}, "null": {"strict": None}, "on": {"strict": True}, "off": {"strict": False}}
function_tools: Final = [
{"type": "function", "name": name, "parameters": {"type": "object"}, **strict}
for name, strict in strict_variants.items()
]
chat_tools, _ = LiteLLMCompletionResponsesConfig.transform_responses_api_tools_to_chat_completion_tools(
tools=[*function_tools, {"type": "namespace", "name": "ns", "tools": function_tools}]
)
sent_strict: Final = {tool["function"]["name"]: tool["function"].get("strict", "absent") for tool in chat_tools}
assert sent_strict == {
"unset": "absent",
"null": "absent",
"on": True,
"off": False,
"ns__unset": "absent",
"ns__null": "absent",
"ns__on": True,
"ns__off": False,
}
@pytest.mark.parametrize("global_drop_params", [False, True])
def test_malformed_tool_flags_answer_400_unless_drop_params_drops_them(
self, monkeypatch: pytest.MonkeyPatch, global_drop_params: bool