> ## Documentation Index
> Fetch the complete documentation index at: https://docs.grantex.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Google ADK

> Scope-enforced plain function tools for Google Agent Development Kit.

## Install

```bash theme={null}
pip install grantex-adk
```

Google ADK is a peer dependency:

```bash theme={null}
pip install google-adk
```

## Quick Start

```python theme={null}
from grantex_adk import create_grantex_tool
from google.adk import Agent

read_calendar = create_grantex_tool(
    name="read_calendar",
    description="Read upcoming calendar events",
    grant_token=grant_token,       # JWT from Grantex authorization flow
    required_scope="calendar:read",
    func=get_calendar_events,
)

# Google ADK uses plain functions as tools
agent = Agent(
    model="gemini-2.0-flash",
    name="assistant",
    tools=[read_calendar],
)
```

If the grant token doesn't include the required scope, `create_grantex_tool` raises a `PermissionError` immediately.

## API Reference

### `create_grantex_tool()`

Creates a plain function with the correct `__name__` and `__doc__` for ADK tool discovery, with offline scope enforcement.

| Parameter        | Type                 | Description                             |
| ---------------- | -------------------- | --------------------------------------- |
| `name`           | `str`                | Tool name (becomes `__name__`)          |
| `description`    | `str`                | Tool description (becomes `__doc__`)    |
| `grant_token`    | `str`                | JWT grant token from Grantex            |
| `required_scope` | `str`                | Scope that must be present in the token |
| `func`           | `Callable[..., str]` | The function to wrap                    |

### `get_tool_scopes(grant_token)`

Returns the scopes embedded in a grant token (offline, no network call).

### `decode_jwt_payload(token)`

Decodes the payload of a JWT without verifying the signature.

## Requirements

* Python 3.9+
* `grantex` >= 0.1.0
* `google-adk` >= 0.2.0 (peer dependency)