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AnthropicLlm ignores tool_config: function calling mode NONE or ANY never reaches Claude聽#7633
Description
馃敶 Required Information
Describe the Bug:
AnthropicLlm (and Claude) always send tool_choice={"type": "auto"} when the agent has tools. The function calling mode set in generate_content_config.tool_config is dropped, so with a Claude model:
mode="NONE"does not stop tool calls.mode="ANY"does not force a tool call.mode="ANY", allowed_function_names=["x"]does not force toolx.
tool_config is how ADK sets tool choice (the answer on #773). Gemini and LiteLlm honor it (LiteLlm maps ANY to required and NONE to none). ADK's own model_consult force plugin relies on it too (_force_escalation_plugin.py:310-313 sets ANY with allowed_function_names=[tool]), so that forcing has no effect on Claude either.
Steps to Reproduce:
- Create an
Agentwithmodel=AnthropicLlm(...), a function tool, andgenerate_content_config=GenerateContentConfig(tool_config=ToolConfig(function_calling_config=FunctionCallingConfig(mode="NONE"))). - Run it with
InMemoryRunner.run_async. - Look at the
tool_choicesent tomessages.create(the script below fakes the SDK call to record it). - Repeat with
mode="ANY"and withmode="ANY", allowed_function_names=["get_weather"].
Expected Behavior:
NONE None -> {'type': 'none'}
ANY None -> {'type': 'any'}
ANY ['get_weather'] -> {'type': 'tool', 'name': 'get_weather'}
Observed Behavior:
NONE None -> {'type': 'auto'}
ANY None -> {'type': 'auto'}
ANY ['get_weather'] -> {'type': 'auto'}
Environment Details:
- ADK Library Version (pip show google-adk): 2.12.0, main at 662b017
- Desktop OS: macOS 26.6.2
- Python Version (python -V): Python 3.12.13
Model Information:
- Are you using LiteLLM: No
- Which model is being used:
AnthropicLlm(model="claude-sonnet-4-5"), withAsyncMessages.createfaked (anthropic 1.14.0), no real call
馃煛 Optional Information
Root cause:
src/google/adk/models/anthropic_llm.py:1255-1259 in AnthropicLlm.generate_content_async hardcodes the choice:
tool_choice = (
anthropic_types.ToolChoiceAutoParam(type="auto")
if llm_request.tools_dict
else NOT_GIVEN
)llm_request.config.tool_config is not read anywhere in the file. The streaming and non-streaming paths both use this value.
Minimal Reproduction Code:
import asyncio, os
from unittest import mock
from anthropic import types as at
from anthropic.resources.messages import AsyncMessages
from google.adk.agents import Agent
from google.adk.models.anthropic_llm import AnthropicLlm
from google.adk.runners import InMemoryRunner
from google.genai import types
os.environ.setdefault("ANTHROPIC_API_KEY", "fake")
sent = []
async def fake_create(self, **kwargs):
sent.append(kwargs)
return at.Message(
id="m", content=[at.TextBlock(text="ok", type="text")],
model=kwargs["model"], role="assistant", stop_reason="end_turn",
stop_sequence=None, type="message",
usage=at.Usage(input_tokens=1, output_tokens=1))
def get_weather(city: str) -> str:
"""Returns the weather for a city."""
return f"Sunny in {city}"
async def run(fc):
agent = Agent(
name="weather", model=AnthropicLlm(model="claude-sonnet-4-5"),
tools=[get_weather],
generate_content_config=types.GenerateContentConfig(
tool_config=types.ToolConfig(function_calling_config=fc)))
runner = InMemoryRunner(agent=agent, app_name="r")
s = await runner.session_service.create_session(app_name="r", user_id="u")
sent.clear()
async for _ in runner.run_async(
user_id="u", session_id=s.id,
new_message=types.Content(role="user", parts=[types.Part(text="Paris?")])):
pass
print(fc.mode.value, fc.allowed_function_names, "->", sent[0]["tool_choice"])
async def main():
with mock.patch.object(AsyncMessages, "create", fake_create):
await run(types.FunctionCallingConfig(mode="NONE"))
await run(types.FunctionCallingConfig(mode="ANY"))
await run(types.FunctionCallingConfig(
mode="ANY", allowed_function_names=["get_weather"]))
asyncio.run(main())How often has this issue occurred?:
- Always (100%)
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