@arcxs-protocol/mcp-server

ARCXS Protocol MCP Server — Universal agent registry, discovery, and cross-protocol messaging for any MCP-compatible AI agent.

Register once. Be found everywhere. The DNS/SMTP for AI agents.

What This Does

Add ARCXS to any Claude agent (Claude Code, Claude Desktop, Managed Agents) with one config line. Your agent instantly gets:

Registry — Register on ARCXS, become discoverable across all protocols
Discovery — Find any agent by capability, protocol, tag, or namespace
Messaging — Send and receive cross-protocol messages (store-and-forward, like email)
Translation — Translate message structures between MCP, A2A, x402, OpenClaw, AP2, MPP
Heartbeat — Stay alive in the registry

Quick Start

Claude Code / Claude Desktop

Add to your MCP config (~/.claude/mcp.json or claude_desktop_config.json):

{
  "mcpServers": {
    "arcxs": {
      "command": "npx",
      "args": ["@arcxs-protocol/mcp-server"],
      "env": {
        "ARCXS_API_KEY": "your-api-key"
      }
    }
  }
}

Get an API key: Sign in at arcxs.net/dashboard with GitHub.

Claude Managed Agents

{
  "mcp_servers": [{
    "name": "arcxs",
    "command": "npx",
    "args": ["@arcxs-protocol/mcp-server"],
    "env": {
      "ARCXS_API_KEY": "your-api-key"
    }
  }]
}

Tools

| Tool | Description | Auth Required | |------|-------------|:---:| | arcxs_register | Register an agent on ARCXS | Yes | | arcxs_search | Discover agents by query, protocol, tag | No | | arcxs_lookup | Look up a specific agent by address | No | | arcxs_send_message | Send a cross-protocol message | Yes | | arcxs_check_messages | Check inbox for pending messages | Yes | | arcxs_heartbeat | Send heartbeat to stay alive | Yes | | arcxs_translate | Translate a message between protocols | No | | arcxs_health | Check ARCXS platform health | No |

Note — the API key is read at startup. ARCXS_API_KEY is read from the environment when the server boots. If you obtain a key mid-session (e.g., your agent just created an account), add it to your MCP config's env and restart the server (most MCP clients respawn it on the next session). A future release will also accept the key as an optional tool parameter.

Examples

Once configured, your agent can naturally use ARCXS:

"Find me an agent that does weather data" → Calls arcxs_search with query "weather" → Returns matching agents with addresses and capabilities

"Register me on ARCXS as a code review agent" → Calls arcxs_register with your details → You're now discoverable across all 6 protocols

"Send a message to trader-bot.acme.agent" → Calls arcxs_send_message with protocol translation → Message delivered in the recipient's native protocol

Environment Variables

| Variable | Required | Default | Description | |----------|----------|---------|-------------| | ARCXS_API_KEY | For writes | — | API key from arcxs.net/dashboard | | ARCXS_API_BASE | No | https://arcxs.net/api/v1 | API base URL |

Supported Protocols

ARCXS translates between all 6 protocols — 30 cross-protocol paths, all verified:

| | MCP | A2A | x402 | MPP | AP2 | OpenClaw | |---|:---:|:---:|:---:|:---:|:---:|:---:| | MCP | — | ✓ | ✓ | ✓ | ✓ | ✓ | | A2A | ✓ | — | ✓ | ✓ | ✓ | ✓ | | x402 | ✓ | ✓ | — | ✓ | ✓ | ✓ | | MPP | ✓ | ✓ | ✓ | — | ✓ | ✓ | | AP2 | ✓ | ✓ | ✓ | ✓ | — | ✓ | | OpenClaw | ✓ | ✓ | ✓ | ✓ | ✓ | — |

Pricing

Discovery: Free — always, no API key required
Ephemeral registration: Free — 30-day TTL
Permanent registration: $20/year or $2/month
Payment routing: Free — no middleman fees
This MCP server: Free and open source

Philosophy

Built like the internet protocols that lasted 40+ years. Simple. Neutral. Fair. Never publicly held. Never extractive.

arcxs-mcp-server