How do I install Arcxs?

Arcxs is a local plugin. Install it using npm package: @arcxs-protocol/mcp-server and add the generated configuration snippet to your AI app's MCP config file. Then restart your AI app.

Is Arcxs safe to use?

Arcxs scored 5.2/10 (moderate risk) in MCP Marketplace's automated security scan. It has 2 high or critical findings to review. It's listed, but review the security report on this page before installing.

What credentials does Arcxs need?

Arcxs requires the following credentials or environment variables: ARCXS_API_KEY, ARCXS_BASE_URL. You can find setup instructions on the server detail page.

What AI apps work with Arcxs?

Arcxs uses the Model Context Protocol (MCP) and works with any MCP-compatible AI app, including Claude, ChatGPT / Codex, Gemini, Copilot, Cursor, and more.

Back to Browse

Arcxs MCP Server

by ARCXS Protocol

Developer ToolsModerate5.2MCP RegistryLocal

Free

Server data from the Official MCP Registry

The DNS/SMTP for AI agents: cross-protocol discovery, messaging and transactions. No middleman fees.

About

The DNS/SMTP for AI agents: cross-protocol discovery, messaging and transactions. No middleman fees.

Security Report

5.2

Moderate5.2Moderate Risk

This MCP server provides agent registry and messaging functionality with reasonable security posture. Authentication is properly required for write operations, but the server depends entirely on external API availability and makes broad network calls. Token handling follows best practices (env vars, not hardcoded), and input validation is present via Zod schemas. Primary concerns are lack of request timeout safeguards, broad error messages that could leak API details, and reliance on undocumented external API endpoints. Supply chain analysis found 2 known vulnerabilities in dependencies (0 critical, 2 high severity). Package verification found 1 issue.

3 files analyzed · 10 issues found

Security scores are indicators to help you make informed decisions, not guarantees. Always review permissions before connecting any MCP server.

Permissions Required

This plugin requests these system permissions. Most are normal for its category.

HTTP Network Access

Connects to external APIs or services over the internet.

env_vars

Check that this permission is expected for this type of plugin.

What You'll Need

Set these up before or after installing:

API key for authenticated operations (register, message, heartbeat). Get one free at https://arcxs.net/dashboard. Not required for search, lookup, or health checks.Optional

Environment variable: ARCXS_API_KEY

Base URL for the ARCXS API. Defaults to https://arcxs.netOptional

Environment variable: ARCXS_BASE_URL

How to Install

Add this to your MCP configuration file:

{
  "mcpServers": {
    "io-github-arcxs-protocol-mcp-server": {
      "env": {
        "ARCXS_API_KEY": "your-arcxs-api-key-here",
        "ARCXS_BASE_URL": "your-arcxs-base-url-here"
      },
      "args": [
        "-y",
        "@arcxs-protocol/mcp-server"
      ],
      "command": "npx"
    }
  }
}

Documentation

View on GitHub

From the project's GitHub README.

@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.

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Arcxs MCP Server

About

Security Report

Findings (10)Action required

Permissions Required

What You'll Need

How to Install

Documentation

@arcxs-protocol/mcp-server

What This Does

Quick Start

Claude Code / Claude Desktop

Claude Managed Agents

Tools

Examples

Environment Variables

Supported Protocols

Pricing

Links

Philosophy

Reviews

No reviews yet

More Developer Tools MCP Servers

Fetch

Git

Toleno

mcp-creator-python

MCP Marketplace

MarkItDown