---
title: "A2A agent (JSON-RPC, v1.0)"
method: POST
path: "/_api/a2a"
tags: ["AI agents"]
---

# A2A agent (JSON-RPC, v1.0)

`POST /_api/a2a`

## Request

- Base URL: `https://shadowalpha.online`
- URL: `https://shadowalpha.online/_api/a2a`
- Auth: none declared

A2A v1.0 JSON-RPC binding; method SendMessage. Agent card: /.well-known/agent-card.json. Paid skills answer with HTTP 402 and a Payment challenge.

## Request body

- object

## Response `200`

JSON-RPC response.

## Other responses

- `402`: Payment required for a paid skill.

---

[API](https://skmtc.dev/shadowalpha/apis/shadowgraph-api.md) · [All operations](https://skmtc.dev/shadowalpha/apis/shadowgraph-api/llms.txt) · [OpenAPI document](https://skmtc.dev/shadowalpha/apis/shadowgraph-api/revisions/1b62d5453408?raw)