Brian Fox
3256a679da
Merge https://github.com/google/adk-python/pull/4531 **Problem:** JSON Schema allows `true` and `false` as valid boolean schemas, where `true` accepts any value and `false` rejects all values. Some MCP servers use this pattern for unconstrained fields. E.g. [mcp-grafana](https://github.com/grafana/mcp-grafana) - see [grafana-mcp-list-tools.json](https://github.com/user-attachments/files/25392430/grafana-mcp-list-tools.json) which was obtained from `tools/list` The schema sanitizer previously passed booleans through unchanged, causing a Pydantic ValidationError when `_ExtendedJSONSchema` tried to validate them as schema objects. ``` 1 validation error for _ExtendedJSONSchema properties.data.items.properties.model Input should be a valid dictionary or object to extract fields from [type=model_attributes_type, input_value=True, input_type=bool] For further information visit https://errors.pydantic.dev/2.12/v/model_attributes_type Traceback (most recent call last): ... File "/.foo/.venv/lib/python3.13/site-packages/google/adk/runners.py", line 561, in run_async async for event in agen: yield event File "/.foo/.venv/lib/python3.13/site-packages/google/adk/runners.py", line 549, in _run_with_trace async for event in agen: yield event File "/.foo/.venv/lib/python3.13/site-packages/google/adk/runners.py", line 778, in _exec_with_plugin async for event in agen: ...<64 lines>... yield event File "/.foo/.venv/lib/python3.13/site-packages/google/adk/runners.py", line 538, in execute async for event in agen: yield event File "/.foo/.venv/lib/python3.13/site-packages/google/adk/agents/base_agent.py", line 294, in run_async async for event in agen: yield event File "/.foo/.venv/lib/python3.13/site-packages/google/adk/agents/llm_agent.py", line 468, in _run_async_impl async for event in agen: ...<5 lines>... should_pause = True File "/.foo/.venv/lib/python3.13/site-packages/google/adk/flows/llm_flows/base_llm_flow.py", line 427, in run_async async for event in agen: last_event = event yield event File "/.foo/.venv/lib/python3.13/site-packages/google/adk/flows/llm_flows/base_llm_flow.py", line 446, in _run_one_step_async async for event in agen: yield event File "/.foo/.venv/lib/python3.13/site-packages/google/adk/flows/llm_flows/base_llm_flow.py", line 578, in _preprocess_async await tool.process_llm_request( tool_context=tool_context, llm_request=llm_request ) File "/.foo/.venv/lib/python3.13/site-packages/google/adk/tools/base_tool.py", line 129, in process_llm_request llm_request.append_tools([self]) ~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^ File "/.foo/.venv/lib/python3.13/site-packages/google/adk/models/llm_request.py", line 255, in append_tools declaration = tool._get_declaration() File "/.foo/.venv/lib/python3.13/site-packages/google/adk/tools/mcp_tool/mcp_tool.py", line 200, in _get_declaration parameters = _to_gemini_schema(input_schema) File "/.foo/.venv/lib/python3.13/site-packages/google/adk/tools/_gemini_schema_util.py", line 218, in _to_gemini_schema json_schema=_ExtendedJSONSchema.model_validate(sanitized_schema), ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^ File "/.foo/.venv/lib/python3.13/site-packages/pydantic/main.py", line 716, in model_validate return cls.__pydantic_validator__.validate_python( ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^ obj, ^^^^ ...<5 lines>... by_name=by_name, ^^^^^^^^^^^^^^^^ ) ^ pydantic_core._pydantic_core.ValidationError: 1 validation error for _ExtendedJSONSchema properties.data.items.properties.model Input should be a valid dictionary or object to extract fields from [type=model_attributes_type, input_value=True, input_type=bool] For further information visit https://errors.pydantic.dev/2.12/v/model_attributes_type ``` **Solution:** Convert boolean schemas to `{"type": "object"}` as the closest approximation available in Gemini's schema model. Co-authored-by: Xuan Yang <xygoogle@google.com> COPYBARA_INTEGRATE_REVIEW=https://github.com/google/adk-python/pull/4531 from onematchfox:fix-gemini-schema-bool 383ac0c0c3ab78d77be4503f5d6b9ad26c41b0db PiperOrigin-RevId: 875219362
Agent Development Kit (ADK)
An open-source, code-first Python framework for building, evaluating, and deploying sophisticated AI agents with flexibility and control.
Important Links: Docs, Samples, Java ADK, Go ADK & ADK Web.
</html>Agent Development Kit (ADK) is a flexible and modular framework that applies software development principles to AI agent creation. It is designed to simplify building, deploying, and orchestrating agent workflows, from simple tasks to complex systems. While optimized for Gemini, ADK is model-agnostic, deployment-agnostic, and compatible with other frameworks.
π₯ What's new
-
Custom Service Registration: Add a service registry to provide a generic way to register custom service implementations to be used in FastAPI server. See short instruction. (391628f)
-
Rewind: Add the ability to rewind a session to before a previous invocation (9dce06f).
-
New CodeExecutor: Introduces a new AgentEngineSandboxCodeExecutor class that supports executing agent-generated code using the Vertex AI Code Execution Sandbox API (ee39a89)
β¨ Key Features
-
Rich Tool Ecosystem: Utilize pre-built tools, custom functions, OpenAPI specs, MCP tools or integrate existing tools to give agents diverse capabilities, all for tight integration with the Google ecosystem.
-
Code-First Development: Define agent logic, tools, and orchestration directly in Python for ultimate flexibility, testability, and versioning.
-
Agent Config: Build agents without code. Check out the Agent Config feature.
-
Tool Confirmation: A tool confirmation flow(HITL) that can guard tool execution with explicit confirmation and custom input.
-
Modular Multi-Agent Systems: Design scalable applications by composing multiple specialized agents into flexible hierarchies.
-
Deploy Anywhere: Easily containerize and deploy agents on Cloud Run or scale seamlessly with Vertex AI Agent Engine.
π Installation
Stable Release (Recommended)
You can install the latest stable version of ADK using pip:
pip install google-adk
The release cadence is roughly bi-weekly.
This version is recommended for most users as it represents the most recent official release.
Development Version
Bug fixes and new features are merged into the main branch on GitHub first. If you need access to changes that haven't been included in an official PyPI release yet, you can install directly from the main branch:
pip install git+https://github.com/google/adk-python.git@main
Note: The development version is built directly from the latest code commits. While it includes the newest fixes and features, it may also contain experimental changes or bugs not present in the stable release. Use it primarily for testing upcoming changes or accessing critical fixes before they are officially released.
π€ Agent2Agent (A2A) Protocol and ADK Integration
For remote agent-to-agent communication, ADK integrates with the A2A protocol. See this example for how they can work together.
π Documentation
Explore the full documentation for detailed guides on building, evaluating, and deploying agents:
π Feature Highlight
Define a single agent:
from google.adk.agents import Agent
from google.adk.tools import google_search
root_agent = Agent(
name="search_assistant",
model="gemini-2.5-flash", # Or your preferred Gemini model
instruction="You are a helpful assistant. Answer user questions using Google Search when needed.",
description="An assistant that can search the web.",
tools=[google_search]
)
Define a multi-agent system:
Define a multi-agent system with coordinator agent, greeter agent, and task execution agent. Then ADK engine and the model will guide the agents to work together to accomplish the task.
from google.adk.agents import LlmAgent, BaseAgent
# Define individual agents
greeter = LlmAgent(name="greeter", model="gemini-2.5-flash", ...)
task_executor = LlmAgent(name="task_executor", model="gemini-2.5-flash", ...)
# Create parent agent and assign children via sub_agents
coordinator = LlmAgent(
name="Coordinator",
model="gemini-2.5-flash",
description="I coordinate greetings and tasks.",
sub_agents=[ # Assign sub_agents here
greeter,
task_executor
]
)
Development UI
A built-in development UI to help you test, evaluate, debug, and showcase your agent(s).
Evaluate Agents
adk eval \
samples_for_testing/hello_world \
samples_for_testing/hello_world/hello_world_eval_set_001.evalset.json
π€ Contributing
We welcome contributions from the community! Whether it's bug reports, feature requests, documentation improvements, or code contributions, please see our
- General contribution guideline and flow.
- Then if you want to contribute code, please read Code Contributing Guidelines to get started.
Community Repo
We have adk-python-community repo that is home to a growing ecosystem of community-contributed tools, third-party service integrations, and deployment scripts that extend the core capabilities of the ADK.
Vibe Coding
If you want to develop agent via vibe coding the llms.txt and the llms-full.txt can be used as context to LLM. While the former one is a summarized one and the later one has the full information in case your LLM has big enough context window.
Community Events
- [Completed] ADK's 1st community meeting on Wednesday, October 15, 2025. Remember to join our group to get access to the recording, and deck.
π License
This project is licensed under the Apache 2.0 License - see the LICENSE file for details.
Happy Agent Building!