# Agent Development Kit (ADK) 2.0

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<h2 align="center">
  <img src="https://raw.githubusercontent.com/google/adk-python/main/assets/agent-development-kit.png" width="256"/>
</h2>
<h3 align="center">
  An open-source, code-first Python framework for building, evaluating, and deploying sophisticated AI agents with flexibility and control.
</h3>
<h3 align="center">
  Important Links:
  <a href="https://google.github.io/adk-docs/">Docs</a>,
  <a href="https://github.com/google/adk-samples">Samples</a> &
  <a href="https://github.com/google/adk-web">ADK Web</a>.
</h3>

______________________________________________________________________

> **⚠️ BREAKING CHANGES FROM 1.x**
>
> This release includes breaking changes to the agent API, event model, and
> session schema. **Sessions generated by ADK 2.0 are readable by ADK 1.28+
> (extra fields will be ignored), but are incompatible with older 1.x versions.**

______________________________________________________________________

## 🔥 What's New in 2.0

- **Workflow Runtime**: A graph-based execution engine for composing
  deterministic execution flows for agentic apps, with support for routing,
  fan-out/fan-in, loops, retry, state management, dynamic nodes,
  human-in-the-loop, and nested workflows.

- **Task API**: Structured agent-to-agent delegation with multi-turn task
  mode, single-turn controlled output, mixed delegation patterns,
  human-in-the-loop, and task agents as workflow nodes.

## 🚀 Installation

```bash
pip install google-adk
```

**Requirements:** Python 3.10+.

To install optional integrations, you can use the following command:

```bash
pip install "google-adk[extensions]"
```

The release cadence is roughly bi-weekly.

## Quick Start

> **Beginner Note:** ADK applications are built using two main classes:
> **`Agent`** (defines an AI's instructions, tools, and behavior) and
> **`Workflow`** (orchestrates agents and tasks in a graph-based flow).

### Agent

```python
from google.adk import Agent

root_agent = Agent(
    name="greeting_agent",
    model="gemini-2.5-flash",
    instruction="You are a helpful assistant. Greet the user warmly.",
)
```

### Workflow

```python
from google.adk import Agent, Workflow

generate_fruit_agent = Agent(
    name="generate_fruit_agent",
    instruction="Return the name of a random fruit. Return only the name.",
)

generate_benefit_agent = Agent(
    name="generate_benefit_agent",
    instruction="Tell me a health benefit about the specified fruit.",
)

root_agent = Workflow(
    name="root_agent",
    edges=[("START", generate_fruit_agent, generate_benefit_agent)],
)
```

### Run Locally

```bash
# Interactive CLI
adk run path/to/my_agent

# Web UI (supports multi-agent directories or pointing directly to a single agent folder)
adk web path/to/agents_dir
```

## 📚 Documentation

- **Getting Started**: https://google.github.io/adk-docs/
- **Samples**: See `contributing/workflow_samples/` and
  `contributing/task_samples/` for workflow and task API examples.

## 🤝 Contributing

See [CONTRIBUTING.md](CONTRIBUTING.md) for details.

## 📄 License

This project is licensed under the Apache 2.0 License — see the
[LICENSE](LICENSE) file for details.
