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

# Agent Endpoints

> Where to send A2A JSON-RPC requests and where to read the agent card.

This page describes the URLs exposed at startup for A2A communication.

## Endpoint Paths

For any agent base URL, the paths are:

* A2A JSON-RPC endpoint: `POST /`
* Agent card endpoint: `GET /.well-known/agent-card.json`

## Startup Output

At startup, `aion serve` prints both proxy and direct agent URLs.

Example format:

```text theme={null}
Proxy API: http://localhost:8000
Agents:
  hello-world:
    Card: http://localhost:8001/.well-known/agent-card.json
    Card (Proxy): http://localhost:8000/agents/hello-world/.well-known/agent-card.json
    RPC: http://localhost:8001
    RPC (Proxy): http://localhost:8000/agents/hello-world/
```

## Single Agent Configured

If only one agent is configured, use that agent root URL directly.

Example:

* `POST http://localhost:8001/`
* `GET http://localhost:8001/.well-known/agent-card.json`

## Multiple Agents Configured

If multiple agents are configured, you have two access options:

1. Proxy URL with `agent_id` path segment:
   `http://{proxy_host}:{proxy_port}/agents/{agent_id}/`
2. Direct URL on each agent's own port:
   `http://{agent_host}:{agent_port}/`

The `agent_id` value is the ID defined in `aion.yaml`.

Example for an agent ID `hello-world`:

* Proxy RPC: `POST http://localhost:8000/agents/hello-world/`
* Proxy card: `GET http://localhost:8000/agents/hello-world/.well-known/agent-card.json`
* Direct RPC: `POST http://localhost:8001/`
* Direct card: `GET http://localhost:8001/.well-known/agent-card.json`

## Port Assignment

If you do not pin ports, the SDK assigns them automatically and prints them at startup.

For port configuration options, see:

* [`aion serve`](../running/aion-serve)
* [`aion.yaml Configuration`](../configuration/aion-yaml)