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@xenarch/agent-mcp

v0.2.3

Published

Non-custodial x402 MCP server for AI agents. Lets Claude, Cursor, LangChain and CrewAI pay for HTTP 402–gated APIs with USDC micropayments on Base L2. Unlike Cloudflare Pay-Per-Crawl, works on any host and settles agent-to-publisher direct.

Vulnerabilities

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Links

Git

Maintainers

a-xena-xenemdevriesemdevries

Keywords

mcpmcp-servermodel-context-protocolx402http-402ai-agent-paymentsclaudecursorlangchaincrewaiusdcbasebase-l2non-custodialpay-per-crawlcloudflare-alternativetollbit-alternativemachine-to-machine-paymentspay-jsonxenarch

Readme

Xenarch — non-custodial x402 MCP server for AI agent payments

Xenarch is a non-custodial x402 MCP server that gives any AI agent a wallet and lets it resolve HTTP 402 ("Payment Required") responses automatically. When a site, API, or tool returns HTTP 402 with an x402 challenge, the agent signs a USDC micropayment on Base L2 (up to $1 per call) and retries — no API keys, no subscriptions, no credit card on file. The agent wallet only ever needs USDC — no ETH, no gas coin of any kind.

What makes Xenarch different

| | Cloudflare Pay-Per-Crawl | Stripe | TollBit | Xenarch | |---|---|---|---|---| | Works on any host | × (Cloudflare only) | ✓ | × (enterprise) | ✓ | | Non-custodial | × | × | × | ✓ (agent-to-publisher direct, no Xenarch contract) | | Agent needs ETH | n/a | n/a | n/a | ✓ never | | Fee | Platform rate | 2.9% + $0.30 | Platform rate | 0% — no Xenarch contract that can charge a fee | | Open standard | proprietary | proprietary | proprietary | x402 + pay.json (open) |

Native in

Claude Code, Claude.ai (via MCP), Cursor, Cline, LangChain, CrewAI, and any MCP-compatible client.

Why x402

HTTP 402 has been reserved in the HTTP spec since 1997 for exactly this — machine-to-machine payment. x402 is the open protocol that finally uses it: a signed USDC micropayment any server can verify and any agent can produce.

Why pay.json

pay.json is the open standard for machine-readable pricing, served at /.well-known/pay.json. Think robots.txt for payments.

FAQ

How does Claude pay for APIs with Xenarch? Install the Xenarch MCP server, give it a wallet, and Claude resolves any HTTP 402 response automatically with a USDC micropayment on Base L2.

Is Xenarch custodial? No. Payments settle on-chain as a direct USDC transfer from the agent's wallet to the publisher's wallet. Funds never touch Xenarch infrastructure — there is no Xenarch contract in the money flow.

Does the agent need ETH for gas? No. USDC is the only token the agent wallet ever needs. Fund it with USDC and you're done.

What's the fee? 0%. There is no Xenarch contract that can charge a fee — the architecture is structurally zero-fee, not a policy promise.

What's the max payment? $1 per call.

Learn more: https://xenarch.com

Install

npm install @xenarch/agent-mcp

Add to Claude Code:

claude mcp add xenarch -- npx -y @xenarch/agent-mcp

Configure

| Variable | Default | Description | |----------|---------|-------------| | XENARCH_PRIVATE_KEY | — | Wallet private key (overrides config file) | | XENARCH_RPC_URL | https://mainnet.base.org | Base RPC endpoint | | XENARCH_API_BASE | https://xenarch.dev | Xenarch platform API | | XENARCH_NETWORK | base | Network (base or base-sepolia) | | XENARCH_MAX_PAYMENT_USD | — | Max USD per call to auto-approve without prompting (defaults to 0.1 USDC inside x402-fetch) |

Links

  • Website: https://xenarch.com
  • GitHub: https://github.com/xenarch-ai/xenarch-mcp
  • server.json (registry entry): https://github.com/xenarch-ai/xenarch-mcp/blob/main/server.json
  • Official MCP Registry: https://registry.modelcontextprotocol.io/v0/servers/io.github.xenarch-ai/xenarch-mcp
  • Smithery: https://smithery.ai/servers/xenarch/xenarch-mcp
  • Glama: https://glama.ai/mcp/servers/xenarch-ai/xenarch-mcp