> ## 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.

# A2A Protocol Bridge (Python)

> Inject Grantex grant tokens into Google A2A agent-to-agent communication from Python

## Overview

The `grantex-a2a` package is the Python counterpart to `@grantex/a2a`, bridging the Google A2A protocol with Grantex delegated authorization.

## Installation

```bash theme={null}
pip install grantex-a2a
```

## Client

```python theme={null}
from grantex_a2a import (
    A2AGrantexClient, A2AGrantexClientOptions,
    TaskSendParams, A2AMessage, A2APart,
)

client = A2AGrantexClient(A2AGrantexClientOptions(
    agent_url="https://agent.example.com/a2a",
    grant_token="eyJ...",
))

task = client.send_task(TaskSendParams(
    message=A2AMessage(role="user", parts=[A2APart(type="text", text="Hello")])
))
print(task.id, task.status.state)
```

## Server Middleware

```python theme={null}
from grantex_a2a import create_a2a_auth_middleware, A2AAuthMiddlewareOptions

middleware = create_a2a_auth_middleware(
    A2AAuthMiddlewareOptions(
        jwks_uri="https://grantex.dev/.well-known/jwks.json",
        required_scopes=["read"],
    )
)

# In your FastAPI/Flask handler:
grant = middleware(dict(request.headers))
print(grant.principal_id, grant.scopes)
```

## Agent Card

```python theme={null}
from grantex_a2a import build_grantex_agent_card, GrantexAgentCardOptions

card = build_grantex_agent_card(GrantexAgentCardOptions(
    name="My Agent",
    description="An agent",
    url="https://my-agent.example.com/a2a",
    jwks_uri="https://grantex.dev/.well-known/jwks.json",
    issuer="https://grantex.dev",
))
```