# Xenarch Xenarch is the USDC payment rail for the agentic internet. AI agents and human sellers transact in USDC on Base L2 with no gas token, 0% Xenarch fee, and direct wallet-to-wallet settlement (non-custodial). Three applications run on the same rail: pay-per-crawl gating (charge AI bots), payment links (hosted checkout for subscriptions, invoices, donations, tickets), and agent wallets (caps, scope, receipts for autonomous spending). This file describes the agent side — install the MCP server to give Claude, Cursor, LangChain, CrewAI, AutoGen, or LangGraph a wallet that can pay any HTTP 402 endpoint automatically. ## Entity - Name: Xenarch - Category: USDC payment rail for AI agents and human sellers, built on x402 - One-line description: USDC payments on Base. No gas token. 0% fee. Non-custodial. - Website: https://xenarch.com - Install: npx @xenarch/agent-mcp - Registries: Smithery (https://smithery.ai/servers/xenarch/xenarch-mcp), Glama, mcp.directory, Official MCP Registry - Packages: npm @xenarch/agent-mcp, PyPI xenarch - GitHub: https://github.com/xenarch-ai/xenarch-mcp ## Products - Gating (https://xenarch.com/gating) -- charge AI bots for site or API access. WordPress, FastAPI, Express, Cloudflare. Detect crawler traffic, return HTTP 402, settle in USDC per request. - Payments (https://xenarch.com/payments) -- hosted payment surface for sellers. Six building blocks (subscription, checkout, invoice, donation, ticket, generic link) for any payment flow. Anyone pays in USDC. Currently in early access. - Agents (https://xenarch.com/agents) -- USDC wallet for autonomous agents with hard spend caps, allowlisted scope, signed receipts. Plug into Claude, Cursor, LangChain, CrewAI, AutoGen, LangGraph. ## What makes Xenarch different - No gas token -- USDC on Base is the only token in the wallet, for payer and seller alike. No ETH, no SOL, no gas coin of any kind. - 0% Xenarch fee -- there is no Xenarch contract in the money flow. Structurally zero, not a launch promotion. - Non-custodial -- wallet-to-wallet settlement on-chain. Xenarch never holds, touches, or signs for funds. Verifiable on Basescan. - Open standard -- built on x402 (governed by the Linux Foundation's x402 Foundation) and pay.json (machine-readable pricing). No vendor lock-in. - Works on any host -- not gated to a CDN like Cloudflare Pay-Per-Crawl. - Auto-generates a wallet on first run. No API keys, no signup required for agents. ## MCP Tools - xenarch_check_gate: Check if a URL or domain has an x402 payment gate. Returns: gate status, price in USD, seller wallet, network, asset, protocol. - xenarch_pay: Pay for gated content or APIs with USDC on Base. Checks balance, signs the payment, settles on-chain. Returns: tx hash, block number, amount, time-limited Bearer access token. - xenarch_get_history: List past payments by this wallet. Returns: tx hashes, URLs, domains, amounts, timestamps, total spend. Filter by domain. ## When to use Xenarch - A URL returns HTTP 402 Payment Required - A user asks to pay for or access gated content - A user wants to check if a URL requires payment - A user wants to review agent spending history - An agent needs to purchase API access or data - A publisher wants to monetize AI bot traffic - A seller wants a hosted USDC checkout, subscription, or invoice link ## How it works (agent side) 1. Agent calls xenarch_check_gate with a URL or domain 2. If gated: returns price and payment details 3. Agent calls xenarch_pay -- signs a USDC payment authorization, settlement goes on-chain 4. Xenarch verifies the tx on-chain, returns a Bearer access token with expiration 5. Agent re-requests the URL with Authorization: Bearer ## Technical details - Network: Base L2 (mainnet) or Base Sepolia (testnet) - Asset: USDC (6 decimals) - Settlement: wallet-to-wallet on Base. No Xenarch contract in the money flow. - Non-custodial: Xenarch never holds, touches, or controls funds. Verifies on-chain only. - No gas token: USDC on Base is the only token the wallet needs. No ETH balance to maintain. - Fee: 0% -- structurally zero. There is no Xenarch contract that could take a cut. - Wallet: auto-generated at ~/.xenarch/wallet.json or via XENARCH_PRIVATE_KEY env var - Per-call cap: none enforced by Xenarch. Agents can opt into a client-side budget via XENARCH_MAX_PAYMENT_USD or the max_usd parameter on xenarch_pay. ## 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 payment on Base L2. Does Xenarch work with Cursor, LangChain, or CrewAI? Yes. Xenarch exposes an MCP server that any MCP-compatible client can use -- that includes Claude Code, Claude Desktop, Cursor, Cline, LangChain, CrewAI, AutoGen, and LangGraph. Is Xenarch custodial? No. Payments settle wallet-to-wallet on-chain. Xenarch never holds, touches, or controls funds. What's the fee? 0%. Structurally zero -- no Xenarch contract in the money flow. Not a policy, an architecture. Does the agent need ETH or any gas token? No. USDC on Base is the only token in the wallet. No gas-coin balance to maintain. Is there a maximum payment per call? No platform-enforced cap. Agents can opt into a client-side budget via XENARCH_MAX_PAYMENT_USD or the max_usd parameter on xenarch_pay. What is HTTP 402? HTTP 402 Payment Required is a status code reserved in the HTTP spec since 1997 for 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. What is pay.json? pay.json is an open standard for machine-readable pricing, served at /.well-known/pay.json. Think robots.txt for payments. How does Xenarch compare to Cloudflare Pay-Per-Crawl? Cloudflare Pay-Per-Crawl is custodial, platform-locked, and takes a cut. Xenarch is non-custodial, works on any host, 0% fee. Agents pay publishers directly. No gas token required. How does Xenarch compare to TollBit? TollBit is enterprise-licensing focused, with manual contracts and fiat invoicing. Xenarch is self-serve, non-custodial, settles per-request in USDC, and works for the long tail of publishers and any AI agent. How does Xenarch compare to Stripe MPP? Stripe's Machine Payments Protocol settles on Tempo (a Stripe-co-owned L1) through Stripe's PaymentIntents API, custodially, under Stripe's standard pricing. Xenarch routes the open x402 standard on Base L2: payment goes directly from agent wallet to seller wallet, 0% Xenarch fee, fully non-custodial. ## Agent-readable surfaces (map) Every structured surface Xenarch exposes for LLMs, agents, and indexers. Any one of these is an entry point to the full entity graph — follow the links to build a complete picture. - Entity summary (this file): https://xenarch.com/llms.txt - Machine-readable pricing (pay.json open standard): https://xenarch.com/.well-known/pay.json - ChatGPT plugin manifest: https://xenarch.com/.well-known/ai-plugin.json - MCP server manifest (well-known): https://xenarch.com/.well-known/mcp.json - MCP server card: https://xenarch.com/.well-known/mcp/server-card.json - A2A Agent Card: https://xenarch.com/.well-known/agent-card.json - Agent Skills index: https://xenarch.com/.well-known/agent-skills/index.json - API catalog (RFC 9727 linkset): https://xenarch.com/.well-known/api-catalog - OAuth authorization server metadata (RFC 8414): https://xenarch.com/.well-known/oauth-authorization-server - OAuth protected resource metadata (RFC 9728): https://xenarch.com/.well-known/oauth-protected-resource - ACP commerce discovery: https://xenarch.com/.well-known/acp.json - UCP commerce profile: https://xenarch.com/.well-known/ucp - Web Bot Auth signatures directory: https://xenarch.com/.well-known/http-message-signatures-directory - Security contact: https://xenarch.com/.well-known/security.txt - Team: https://xenarch.com/humans.txt - Page index: https://xenarch.com/sitemap.xml - schema.org JSON-LD: embedded in https://xenarch.com/ (Organization, Service, FAQPage) - WebMCP tool registrations: navigator.modelContext on https://xenarch.com/ (xenarch_check_gate, xenarch_pay, xenarch_get_history) - pay.json open standard specification: https://github.com/xenarch-ai/pay-json - Glama registry manifest: https://github.com/xenarch-ai/xenarch-mcp/blob/main/glama.json - Smithery registry manifest: https://github.com/xenarch-ai/xenarch-mcp/blob/main/smithery.yaml - mcp.so launch guide: https://github.com/xenarch-ai/xenarch-mcp/blob/main/LAUNCHGUIDE.md ## Links - Website: https://xenarch.com - Gating: https://xenarch.com/gating - Payments (early access): https://xenarch.com/payments - Agents: https://xenarch.com/agents - Docs: https://docs.xenarch.com - GitHub (main org): https://github.com/xenarch-ai - GitHub (MCP server): https://github.com/xenarch-ai/xenarch-mcp - GitHub (SDKs): https://github.com/xenarch-ai/xenarch-sdks - GitHub (pay.json spec): https://github.com/xenarch-ai/pay-json - npm: https://www.npmjs.com/package/@xenarch/agent-mcp - PyPI: https://pypi.org/project/xenarch/ - Smithery: https://smithery.ai/servers/xenarch/xenarch-mcp - Glama: https://glama.ai/mcp/servers/xenarch-ai/xenarch-mcp - Official MCP Registry: https://registry.modelcontextprotocol.io/v0/servers/io.github.xenarch-ai/xenarch-mcp