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What is A2A

Agent2Agent (A2A) is Google’s open protocol for AI agents from different vendors and frameworks to communicate. Each agent publishes an Agent Card at /.well-known/agent.json describing its capabilities, endpoints, and auth requirements. Clients discover the card, send a Task, and receive Artifacts back. AlgoVoi runs a live A2A v1.0 agent at api1.ilovechicken.co.uk/.well-known/agent.json with three skills.

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When to use A2A

Cross-framework agents

Your LangGraph agent calling someone’s CrewAI agent, with no SDK lock-in.

Discoverable services

AI agents finding payment-gate services via Agent Card registries.

x402 over A2A

Wrap an x402-paywalled endpoint in an A2A task. Agents pay through the same protocol they discover with.

Long-running tasks

A2A handles streaming and push notifications natively, which fits multi-step agent workflows.

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AlgoVoi’s A2A skills

The live agent card publishes three skills you can call from any A2A-compatible client.

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verify-payment

Verify any on-chain transaction across the 7 supported chains. Input: tx_id, chain. Output: verification status plus the extracted amount, asset, and sender.

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create-checkout

Request a hosted-checkout link without going through the dashboard. Input: amount, currency, preferred_network. Output: checkout URL and token.
create-checkout takes a fiat amount and currency, not chain microunits. AlgoVoi’s price oracle does the conversion. This is by design. Agents shouldn’t have to know per-chain decimals.

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check-status

Poll a checkout link’s status. Input: token. Output: active, paid, expired, or cancelled, plus tx_id when paid.

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Quickstart

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From an A2A client

import { A2AClient } from "@a2a-protocol/sdk-js";

const client = new A2AClient("https://api1.ilovechicken.co.uk");
const card = await client.fetchAgentCard();

const task = await client.sendTask({
  message: {
    parts: [{ kind: "text", text: "verify tx ABCD1234… on algorand:mainnet" }]
  },
  skill: "verify-payment"
});

console.log(task.status, task.artifacts);

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From an MCP-bridged agent

A2A and MCP can co-exist. See the A2A MCP bridge. AlgoVoi’s skills can be exposed to Claude, Cursor, or any MCP-aware agent through the bridge.

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First-mover position

As of 2026-04-22, AlgoVoi is the only live A2A agent in the crypto-payments ecosystem. A probe of 22 candidate domains found zero other deployed payment-gate agents. The Agent Card is published for any AI agent or registry to discover.

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Production gateway only

A2A skills run on the api1.ilovechicken.co.uk gateway, not on the cloud edge. They need direct facilitator and database access. Cloud endpoints proxy normal payment traffic, not A2A skills.

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See also

  • AP2 typically rides on A2A as its transport
  • x402 is used as the payment leg inside A2A skills
  • The A2A spec
  • AlgoVoi’s agent card (live JSON)