Python

This page is generated from the A2A Pack language SDK metadata.

Scaffold

a2a init math-agent --language python

Implementation Contract

Subclass a2a_pack.A2AAgent and implement @a2a.tool methods. Tools are published in the agent card's skills array (A2A spec vocabulary); @skill remains a supported alias of @a2a.tool.

import a2a_pack as a2a
from a2a_pack import A2AAgent, NoAuth, RunContext

class MathAgent(A2AAgent[None, NoAuth]):
    name = "math-agent"
    description = "Math helper"
    auth_model = NoAuth

    @a2a.tool(description="Add two numbers")
    async def sum(self, ctx: RunContext[NoAuth], left: float, right: float) -> dict[str, float]:
        return {"value": left + right}

Local Commands

a2a compile
a2a dev

SDK Package

a2a_pack Python package.

The compiled .a2a/agent.dsl.json is the sidecar contract. The sidecar owns public A2A, MCP, frontend, and invoke endpoints; the language SDK owns native handler execution through the worker protocol.