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x402lint MCP Server

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answering

x402lint is answering right now. Last checked 3 min ago. It exposes 3 tools. Last commit 29 Oct 2026.

Free x402 endpoint linter: unpaid 402 challenge, payTo/asset/amount, CORS, directory readiness.

Uptime history 5 days of history
5 days agonow
100.0%
Uptime 24h
92 of 92 checks
3
Tools
read from the server
100 ms
Response time
average over 24h
0
Stars
last commit 29 Oct 2026

What changed 7

Every tool that appeared, vanished or quietly changed what it asks for. Recorded since 28 October 2026. No other catalogue keeps this.

29 Oct a tool changed version2 times that day
28 Oct a tool changed version4 times that day
28 Oct a tool appeared check_directory_readiness
and 4 more, back to 28 October 2026

Nothing serious here today

Today is the operative word: we check x402lint every 15 minutes and re-read its code on every release. Watch it and you find out the day that stops being true.

Three servers free · no card

Connect this server

Endpoint below is the one we actually reach during checks — not the one copied from a README. Last verified 3 min ago.

run in your terminal
claude mcp add x402lint --transport http https://x402lint.something-agent.workers.dev/mcp
Settings → Connectors → Add custom connector, then paste this address
https://x402lint.something-agent.workers.dev/mcp
~/.codex/config.toml
[mcp_servers.x402lint]
url = "https://x402lint.something-agent.workers.dev/mcp"
.cursor/mcp.json
{
  "mcpServers": {
    "x402lint": {
      "url": "https://x402lint.something-agent.workers.dev/mcp"
    }
  }
}
.vscode/mcp.json
{
  "servers": {
    "x402lint": {
      "type": "http",
      "url": "https://x402lint.something-agent.workers.dev/mcp"
    }
  }
}

Available tools 3

Read directly from the server with tools/list, grouped by what they act on. If a tool disappears, we record the date.

lint
lint_payment_required
Lint a PaymentRequired object you already have (decoded JSON, a JSON string, or the raw base64 PAYMENT-REQUIRED header). Same field/value checks as lint_x402_endpoint, no network access. Free.
lint_x402_endpoint
Unpaid lint of an x402 endpoint: fetches the 402 (GET and POST), then checks the challenge (version, accepts[] fields, CAIP-2 network, payTo/asset/amount sanity, EIP-712 name/version, timeouts, resource), transport (redirects, cache headers, CORS) and discovery files. Returns findings with ids, severities and fixes. Never pays. Free.
directory
check_directory_readiness
Lint an x402 endpoint's unpaid 402 and report, per directory, whether it meets what x402dash (unpaid GET must return 402), x402scan (OpenAPI x-payment-info or /.well-known/x402, input schema), the402 (validator 'payable') and the CDP/PayAI Bazaar (bazaar extension, description <= 500 chars, non-tunnel https host; listing then needs one settled payment) were known to check. Never pays. Free.

Endpoints

URLTransportStateLatencyChecked
https://x402lint.something-agent.workers.dev/mcp streamable-http answering 105 ms 3 min ago

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x402lint — questions

Answers built from our own checks of this server.

What can x402lint do?
It exposes 3 tools, read directly from the server on our last check. Among them: check_directory_readiness, lint_payment_required, lint_x402_endpoint. The full list with descriptions is on this page — we take it from the server itself via tools/list, not from a README. How MCP servers expose tools in the first place →
Is x402lint working right now?
We send a real MCP handshake every 15 minutes. Over the last 24 hours 92 of 92 checks got a reply (100.0%), average response time 100 ms. The bar chart above shows every period we have measured.
How do I connect x402lint?
Copy the ready config from this page. We generate it for Claude Code, Claude Desktop, Codex, Cursor and VS Code, each in the form that client actually reads. It is a remote server, so there is nothing to install — the client connects to the address.
Does x402lint need an API key?
No. x402lint completed a full MCP handshake with us as an anonymous client and listed its tools without asking for anything. All 3 of them are readable on this page. This is what we observed, not what the docs claim.
How fast is x402lint?
It answers our handshake in 100 ms on average, which is faster than 92% of all working MCP servers we measure. That puts it in the quick quarter of the ecosystem. The comparison comes from our own checks across the whole registry, every 15 minutes.
Is x402lint open source?
The code is open source: it is published under the MIT licence, written in TypeScript and 0 stars on GitHub. The licence covers the code in the repository, not the hosted service at x402lint.something-agent.workers.dev, which runs on its operator's own terms.