litellm/tests/test_litellm/responses/test_custom_tool_call.py
mateo-berri ab2c9aed0f fix(responses): normalize tool call id shapes across the anthropic bridge and openai replay
The chat-completions bridge emitted Responses output items whose item ids
were raw Anthropic tool ids (toolu_/srvtoolu_), which OpenAI rejects on
replay with "Expected an ID that begins with 'fc'", breaking router
fallback conversations from gpt-5 to claude models.

Four fixes, composable and independently useful:
- emission: bridge output items get fc_/ctc_-prefixed item ids while
  call_id stays raw so tool_result pairing keeps working (streaming and
  non-streaming share the same helpers)
- openai replay: request transformation drops tool call item ids that do
  not match OpenAI's own shapes instead of forwarding them, gated to
  OpenAI and Azure, since the API accepts the items with no id at all
- anthropic replay: a replayed srvtoolu_ call whose paired server tool
  result is unavailable degrades to a plain client tool_use instead of a
  dangling server_tool_use that 400s the client's tool_result
- tool-only turns no longer emit a message output item with output_text
  text null, matching native OpenAI output
2026-09-01 11:12:24 -07:00

425 lines
18 KiB
Python

"""
Test custom_tool_call adaptation for apply_patch and other custom tools.
This test verifies that when Codex sends custom tools (type="custom"),
LiteLLM bridge correctly:
1. Converts them to function tools for Chat Completions providers
2. Converts function_call responses back to custom_tool_call output items
3. Unwraps the JSON-wrapping arguments to extract the actual input content
"""
import json
import pytest
from typing import Dict, Any, List
from openai.types.responses import ResponseFunctionToolCall
from litellm.responses.litellm_completion_transformation.transformation import (
LiteLLMCompletionResponsesConfig,
)
from litellm.responses.litellm_completion_transformation.custom_tools import (
extract_custom_tool_names,
is_custom_tool_call,
openai_shaped_tool_call_item_id,
unwrap_custom_tool_arguments,
build_tool_call_item_kwargs,
convert_custom_tool_to_function_tool,
_MAX_ARGUMENTS_LEN,
)
from litellm.types.responses.main import CustomToolCallOutputItem
class TestCustomToolUtilities:
"""Test the custom_tools utility functions."""
def test_extract_custom_tool_names(self):
"""Test extraction of custom tool names from tools list."""
tools = [
{"type": "function", "name": "regular_tool"},
{"type": "custom", "name": "apply_patch"},
{"type": "function", "name": "another_tool"},
{"type": "custom", "name": "custom_format"},
]
names = extract_custom_tool_names(tools)
assert names == {"apply_patch", "custom_format"}
def test_extract_custom_tool_names_empty(self):
"""Test extraction with no custom tools."""
tools = [
{"type": "function", "name": "tool1"},
{"type": "function", "name": "tool2"},
]
names = extract_custom_tool_names(tools)
assert names == set()
def test_extract_custom_tool_names_none(self):
"""Test extraction with None input."""
names = extract_custom_tool_names(None)
assert names == set()
def test_is_custom_tool_call_true(self):
"""Test identification of custom tool call."""
custom_names = {"apply_patch", "custom_format"}
assert is_custom_tool_call("apply_patch", custom_names) is True
assert is_custom_tool_call("custom_format", custom_names) is True
def test_is_custom_tool_call_false(self):
"""Test identification of non-custom tool call."""
custom_names = {"apply_patch"}
assert is_custom_tool_call("regular_tool", custom_names) is False
assert is_custom_tool_call("unknown_tool", custom_names) is False
def test_unwrap_custom_tool_arguments(self):
"""Test unwrapping of JSON-wrapped arguments."""
# Test with valid JSON
wrapped = json.dumps({"content": "*** Begin Patch\n*** Add File: test.py\n+hello\n*** End Patch"})
unwrapped = unwrap_custom_tool_arguments(wrapped)
assert unwrapped == "*** Begin Patch\n*** Add File: test.py\n+hello\n*** End Patch"
def test_unwrap_custom_tool_arguments_invalid_json(self):
"""Test unwrapping with invalid JSON returns original."""
raw = "*** Begin Patch\n*** Add File: test.py\n+hello\n*** End Patch"
unwrapped = unwrap_custom_tool_arguments(raw)
assert unwrapped == raw
def test_unwrap_custom_tool_arguments_no_content_key(self):
"""Test unwrapping with JSON but no content key."""
wrapped = json.dumps({"other_key": "value"})
unwrapped = unwrap_custom_tool_arguments(wrapped)
assert unwrapped == wrapped
def test_build_tool_call_item_kwargs_custom_completed(self):
"""A completed custom tool call unwraps the content into `input`."""
wrapped = json.dumps({"content": "patch body"})
kwargs = build_tool_call_item_kwargs(
call_id="c1",
name="apply_patch",
arguments_or_input=wrapped,
status="completed",
custom_tool_names={"apply_patch"},
)
assert kwargs["type"] == "custom_tool_call"
assert kwargs["input"] == "patch body"
assert "arguments" not in kwargs
def test_build_tool_call_item_kwargs_custom_in_progress(self):
"""An in-progress custom tool call seeds an empty input string."""
kwargs = build_tool_call_item_kwargs(
call_id="c2",
name="apply_patch",
arguments_or_input="ignored-until-completed",
status="in_progress",
custom_tool_names={"apply_patch"},
)
assert kwargs["input"] == ""
def test_build_tool_call_item_kwargs_regular_function(self):
"""A regular function call keeps raw arguments and uses function_call type."""
raw = json.dumps({"k": "v"})
kwargs = build_tool_call_item_kwargs(
call_id="c3",
name="get_weather",
arguments_or_input=raw,
status="completed",
custom_tool_names=set(),
)
assert kwargs["type"] == "function_call"
assert kwargs["arguments"] == raw
assert "input" not in kwargs
def test_openai_shaped_tool_call_item_id_prefixes_foreign_ids(self):
"""Anthropic-style tool ids must be normalized to OpenAI's item id
shapes (fc/ctc prefixes) so replaying the item to OpenAI does not 400
with "Expected an ID that begins with 'fc'"."""
assert openai_shaped_tool_call_item_id("function_call", "toolu_01Abc") == "fc_toolu_01Abc"
assert openai_shaped_tool_call_item_id("function_call", "srvtoolu_01Xyz") == "fc_srvtoolu_01Xyz"
assert openai_shaped_tool_call_item_id("custom_tool_call", "toolu_01Abc") == "ctc_toolu_01Abc"
assert openai_shaped_tool_call_item_id("function_call", "fc_already") == "fc_already"
assert openai_shaped_tool_call_item_id("custom_tool_call", "ctc_already") == "ctc_already"
assert openai_shaped_tool_call_item_id("function_call", "") == ""
assert openai_shaped_tool_call_item_id("message", "toolu_01Abc") == "toolu_01Abc"
def test_build_tool_call_item_kwargs_normalizes_item_id_keeps_call_id(self):
"""The streaming item id gets the OpenAI shape while call_id stays raw
so tool_result pairing (which keys off call_id) keeps working."""
function_kwargs = build_tool_call_item_kwargs(
call_id="toolu_01Abc",
name="get_weather",
arguments_or_input="{}",
status="completed",
custom_tool_names=set(),
)
assert function_kwargs["id"] == "fc_toolu_01Abc"
assert function_kwargs["call_id"] == "toolu_01Abc"
custom_kwargs = build_tool_call_item_kwargs(
call_id="toolu_01Def",
name="apply_patch",
arguments_or_input=json.dumps({"content": "patch"}),
status="completed",
custom_tool_names={"apply_patch"},
)
assert custom_kwargs["id"] == "ctc_toolu_01Def"
assert custom_kwargs["call_id"] == "toolu_01Def"
def test_unwrap_custom_tool_arguments_oversized_returns_raw(self):
"""Arguments larger than the safety cap are returned unchanged to avoid
OOM on JSON parsing a pathologically large string."""
oversized = "x" * (_MAX_ARGUMENTS_LEN + 1)
assert unwrap_custom_tool_arguments(oversized) == oversized
def test_unwrap_custom_tool_arguments_empty(self):
"""Empty arguments unwrap to an empty string, not the raw input."""
assert unwrap_custom_tool_arguments("") == ""
def test_convert_custom_tool_to_function_tool_with_format(self):
"""The grammar definition is embedded in the description so the model can
produce correctly-formatted output."""
tool = {
"type": "custom",
"name": "apply_patch",
"description": "Apply a patch",
"format": {
"type": "grammar",
"syntax": "lark",
"definition": "start: begin_patch",
},
}
result = convert_custom_tool_to_function_tool(tool)
assert result is not None
assert result["type"] == "function"
assert "begin_patch" in result["function"]["description"]
assert result["function"]["parameters"]["required"] == ["content"]
def test_convert_custom_tool_to_function_tool_non_custom_returns_none(self):
"""Non-custom tools are not convertible; the caller keeps them as-is."""
assert convert_custom_tool_to_function_tool({"type": "function"}) is None
class TestTransformationCustomTools:
"""Test custom tool handling in transformation logic."""
def test_transform_apply_patch_function_call_to_custom_tool_call(self):
"""Test that apply_patch function_call is converted to custom_tool_call."""
# Simulate a Chat Completion response with apply_patch function call
from litellm.types.utils import ModelResponse, Choices, Message, ChatCompletionMessageToolCall, Function
tool_call = ChatCompletionMessageToolCall(
id="call_abc123",
type="function",
function=Function(
name="apply_patch",
arguments=json.dumps({"content": "*** Begin Patch\n*** Add File: test.py\n+hello\n*** End Patch"}),
),
)
message = Message(role="assistant", content=None, tool_calls=[tool_call])
choices = [Choices(index=0, message=message, finish_reason="tool_calls")]
response = ModelResponse(
id="test_response", choices=choices, created=1234567890, model="gpt-4", object="chat.completion"
)
# Transform with custom tool names
responses_api_request = {
"tools": [{"type": "custom", "name": "apply_patch"}, {"type": "function", "name": "regular_tool"}]
}
result = LiteLLMCompletionResponsesConfig.transform_chat_completion_tools_to_responses_tools(
response, responses_api_request=responses_api_request
)
# Should return a CustomToolCallOutputItem object; ResponsesAPIResponse
# accepts it directly via its output item union.
assert len(result) == 1
item = result[0]
assert isinstance(item, CustomToolCallOutputItem)
assert item.type == "custom_tool_call"
assert item.call_id == "call_abc123"
assert item.name == "apply_patch"
assert item.input == "*** Begin Patch\n*** Add File: test.py\n+hello\n*** End Patch"
assert item.status == "completed"
def test_custom_tool_call_input_item_recovers_payload_from_input(self):
"""A custom_tool_call input item stores its payload in `input`; the
assistant tool call must carry it as a JSON content envelope whether
`arguments` is missing or an empty string."""
for arguments in (None, ""):
item = {
"type": "custom_tool_call",
"call_id": "call_1",
"name": "apply_patch",
"input": "*** Begin Patch\n+hello\n*** End Patch",
}
if arguments is not None:
item["arguments"] = arguments
messages = (
LiteLLMCompletionResponsesConfig._transform_responses_api_function_call_to_chat_completion_message(
function_call=item
)
)
tool_call = messages[0]["tool_calls"][0]
assert tool_call["function"]["arguments"] == json.dumps(
{"content": "*** Begin Patch\n+hello\n*** End Patch"}
)
def test_function_call_input_item_with_empty_arguments_keeps_them_empty(self):
"""A plain function_call input item with empty or missing `arguments`
must produce an empty arguments string, never a `{"content": ...}`
envelope (that recovery is reserved for custom_tool_call items) and
never the literal string "None"."""
for item in (
{
"type": "function_call",
"call_id": "call_2",
"name": "get_weather",
"arguments": "",
"input": "stray value",
},
{
"type": "function_call",
"call_id": "call_3",
"name": "get_weather",
},
):
messages = (
LiteLLMCompletionResponsesConfig._transform_responses_api_function_call_to_chat_completion_message(
function_call=item
)
)
tool_call = messages[0]["tool_calls"][0]
assert tool_call["function"]["arguments"] == ""
def test_transform_regular_function_call_unchanged(self):
"""Test that regular function calls remain as ResponseFunctionToolCall."""
from litellm.types.utils import ModelResponse, Choices, Message, ChatCompletionMessageToolCall, Function
tool_call = ChatCompletionMessageToolCall(
id="call_xyz789",
type="function",
function=Function(name="regular_tool", arguments=json.dumps({"param": "value"})),
)
message = Message(role="assistant", content=None, tool_calls=[tool_call])
choices = [Choices(index=0, message=message, finish_reason="tool_calls")]
response = ModelResponse(
id="test_response", choices=choices, created=1234567890, model="gpt-4", object="chat.completion"
)
# Transform with custom tool names (regular_tool is NOT custom)
responses_api_request = {
"tools": [{"type": "custom", "name": "apply_patch"}, {"type": "function", "name": "regular_tool"}]
}
result = LiteLLMCompletionResponsesConfig.transform_chat_completion_tools_to_responses_tools(
response, responses_api_request=responses_api_request
)
# Should return ResponseFunctionToolCall
assert len(result) == 1
item = result[0]
assert isinstance(item, ResponseFunctionToolCall)
assert item.type == "function_call"
assert item.name == "regular_tool"
assert item.arguments == json.dumps({"param": "value"})
def test_transform_anthropic_tool_call_ids_get_openai_item_id_shape(self):
"""Anthropic tool ids (toolu_/srvtoolu_) surfacing through the bridge
must be emitted with fc/ctc-prefixed item ids so a Responses client can
replay them to OpenAI verbatim, while call_id stays raw for pairing."""
from litellm.types.utils import ModelResponse, Choices, Message, ChatCompletionMessageToolCall, Function
client_call = ChatCompletionMessageToolCall(
id="toolu_01ClientCall",
type="function",
function=Function(name="get_weather", arguments=json.dumps({"city": "SF"})),
)
server_call = ChatCompletionMessageToolCall(
id="srvtoolu_01ServerCall",
type="function",
function=Function(name="web_search", arguments=json.dumps({"query": "zig"})),
)
custom_call = ChatCompletionMessageToolCall(
id="toolu_01CustomCall",
type="function",
function=Function(name="apply_patch", arguments=json.dumps({"content": "patch content"})),
)
message = Message(role="assistant", content=None, tool_calls=[client_call, server_call, custom_call])
choices = [Choices(index=0, message=message, finish_reason="tool_calls")]
response = ModelResponse(
id="test_response", choices=choices, created=1234567890, model="claude-sonnet-4-5", object="chat.completion"
)
responses_api_request = {
"tools": [{"type": "custom", "name": "apply_patch"}, {"type": "function", "name": "get_weather"}]
}
result = LiteLLMCompletionResponsesConfig.transform_chat_completion_tools_to_responses_tools(
response, responses_api_request=responses_api_request
)
assert [item.id for item in result] == [
"fc_toolu_01ClientCall",
"fc_srvtoolu_01ServerCall",
"ctc_toolu_01CustomCall",
]
assert [item.call_id for item in result] == [
"toolu_01ClientCall",
"srvtoolu_01ServerCall",
"toolu_01CustomCall",
]
def test_transform_mixed_tool_calls(self):
"""Test transformation with both custom and regular tool calls."""
from litellm.types.utils import ModelResponse, Choices, Message, ChatCompletionMessageToolCall, Function
custom_call = ChatCompletionMessageToolCall(
id="call_001",
type="function",
function=Function(name="apply_patch", arguments=json.dumps({"content": "patch content"})),
)
regular_call = ChatCompletionMessageToolCall(
id="call_002", type="function", function=Function(name="get_weather", arguments=json.dumps({"city": "SF"}))
)
message = Message(role="assistant", content=None, tool_calls=[custom_call, regular_call])
choices = [Choices(index=0, message=message, finish_reason="tool_calls")]
response = ModelResponse(
id="test_response", choices=choices, created=1234567890, model="gpt-4", object="chat.completion"
)
responses_api_request = {
"tools": [{"type": "custom", "name": "apply_patch"}, {"type": "function", "name": "get_weather"}]
}
result = LiteLLMCompletionResponsesConfig.transform_chat_completion_tools_to_responses_tools(
response, responses_api_request=responses_api_request
)
assert len(result) == 2
# First should be custom_tool_call object
first = result[0]
assert isinstance(first, CustomToolCallOutputItem)
assert first.type == "custom_tool_call"
assert first.name == "apply_patch"
assert first.input == "patch content"
# Second should be function_call
second = result[1]
assert isinstance(second, ResponseFunctionToolCall)
assert second.type == "function_call"
assert second.name == "get_weather"
if __name__ == "__main__":
pytest.main([__file__, "-v"])