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chore: import upstream snapshot with attribution
2026-07-13 13:25:13 +08:00

119 lines
3.5 KiB
Python

# Copyright 2026 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from __future__ import annotations
from typing import Any
from google.adk.agents import Agent
from google.adk.agents.callback_context import CallbackContext
from google.adk.models.llm_request import LlmRequest
from google.adk.models.llm_response import LlmResponse
from google.adk.tools import BaseTool
from google.adk.tools import ToolContext
from google.genai import types
def get_weather(city: str) -> str:
return f"The weather in {city} is sunny."
def before_tool_callback(
tool: BaseTool,
args: dict[str, Any],
tool_context: ToolContext,
) -> dict[str, Any] | None:
"""A callback that runs before a tool is called.
Args:
tool: The tool instance being called.
args: The arguments passed to the tool.
tool_context: The context for the tool execution.
Returns:
A dict containing the mock response if the call should be short-circuited,
or None to proceed with the actual tool call.
"""
# Intercept tool calls for London and return a mocked response
if args.get("city") == "London":
return {
"result": "Weather in London is always rainy (intercepted by callback)."
}
return None
def before_model_callback(
callback_context: CallbackContext,
llm_request: LlmRequest,
) -> LlmResponse | None:
"""A callback that runs before the model is called.
Args:
callback_context: The context for the callback.
llm_request: The request that is about to be sent to the model.
Returns:
An LlmResponse to short-circuit the model call, or None to proceed.
"""
# Short-circuit if the user simply says "Hi"
if llm_request.contents:
last_content = llm_request.contents[-1]
if last_content.parts:
last_part = last_content.parts[-1]
if last_part.text and last_part.text.strip().lower() == "hi":
return LlmResponse(
content=types.Content(
role="model",
parts=[
types.Part.from_text(
text="Hello from before_model callback!"
)
],
)
)
return None
def after_model_callback(
callback_context: CallbackContext,
llm_response: LlmResponse,
) -> LlmResponse:
"""A callback that runs after the model is called."""
if llm_response.usage_metadata:
usage = llm_response.usage_metadata
usage_text = (
"\n\nafter_model_callback: [Token Usage:"
f" Input={usage.prompt_token_count},"
f" Output={usage.candidates_token_count}]"
)
if not llm_response.content:
llm_response.content = types.Content(role="model", parts=[])
llm_response.content.parts.append(types.Part.from_text(text=usage_text))
print(llm_response.content)
return llm_response
root_agent = Agent(
name="callback_demo_agent",
tools=[get_weather],
before_tool_callback=before_tool_callback,
before_model_callback=before_model_callback,
after_model_callback=after_model_callback,
)