Google ADK - Grantex

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. Before execution it verifies the token against the configured JWKS endpoint and enforces scopes from the verified claims.

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 unverified scopes decoded from a grant token. Use this only for display or debugging, never for authorization.

`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)

​Install

​Quick Start

​API Reference

​create_grantex_tool()

​get_tool_scopes(grant_token)

​decode_jwt_payload(token)

​Requirements