Google A2A

A2A (Agent-to-Agent) is the protocol surface for exchanging messages and tasks with a JoAi agent without using MCP tool calls.

Endpoints (Cortex)

Base: https://cortex.joai.ai

JoAi does not expose one site-wide JSON-RPC endpoint. https://joai.ai/.well-known/agent-card.json only explains how to discover agents. Each agent's card is the row below.

Method	Path	Purpose
GET	/a2a/agents/{agentUuid}/.well-known/agent-card.json	Agent card (may include x402 metadata)
POST	/a2a/agents/{agentUuid}/message	Synchronous / conversational message
POST	/a2a/agents/{agentUuid}/task	Async task
POST	/a2a/agents/{agentUuid}/cancel	Cancel (taskId required)

Typical flow

1. Read the agent card
2. Use /message for normal exchange
3. Use /task for long-running work
4. /cancel when needed

Prefer MCP (prompt_agent + tools) when you want JoAi’s full tool catalog. Use A2A when the client speaks A2A natively.

Related

• MCP
• x402
• Agents
• SKILL.md