@xenarch/agent-mcp

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.

Source

npm

Version: 0.2.1

Version published: 4 months ago

Weekly downloads: 101

Maintainers: 2

Weekly downloads

Created: 5 months ago

Source

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.

What makes Xenarch different

	Cloudflare Pay-Per-Crawl	TollBit	Xenarch
Works on any host	❌ (Cloudflare only)	❌ (enterprise)	✅
Non-custodial	❌	❌	✅ (agent-to-publisher direct, no Xenarch contract)
Fee	Platform rate	Platform rate	*0% — no Xenarch contract that can* charge a fee**
Open standard	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 direct from the agent's wallet to the publisher's wallet via a third-party x402 facilitator. Funds never touch Xenarch infrastructure — there is no Xenarch contract in the money flow.

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)