Google ADK

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

Install

pip install grantex-adk

Google ADK is a peer dependency:

pip install google-adk

Quick Start

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)