MCP server · Finance and crypto

402MCP payment helper

Your AI can read a 402 Payment Required message and tell you exactly how to pay and retry.

This is a helper for AI agents that bump into an HTTP 402 Payment Required message. That message means a website or service wants to be paid before it answers. This server reads the message and explains, in plain steps, what is being asked and how to pay and try again.

What is an MCP server? The 30-second version

On its own, your AI can only chat. It cannot talk to other apps or services unless you give it a connection. An MCP server is a small helper program that gives your AI a new skill. This one gives your AI the skill of understanding 402 payment messages and looking up payment options, so it can explain them to you when you ask.

What this MCP server does

You paste a 402 response into your chat and ask your AI what it means. Your AI sends that text to this helper. The helper reads the payment scheme (L402, x402 or MPP), pulls out what is being asked for, and writes back the exact next steps and the retry header. Your AI then shows you those steps in the chat. It can also search a public list of payment solutions and recommend one based on what you tell it.

What you can do with it

Decode a 402 response into plain next steps
Tell you which payment scheme a server speaks
Recommend a payment rail from your requirements
Search an open registry of agent payment solutions
Show the wire format of L402, x402 or MPP
Check whether a public URL speaks 402 (never pays)
Flag expired challenges or mismatched macaroons

Try asking your AI

“Here is a 402 response I got. What does it want and how do I pay?”
“I need an agent payment rail that uses stablecoins and no custody. What do you recommend?”
“Search the registry for x402 solutions with MCP support.”
“Does https://example.com speak 402? Just check, do not pay.”

What it gives back to you

You get back a short explanation in the chat: which scheme it is, what is being asked for, and the exact steps to pay and retry. For recommendations, you get a ranked list with reasons and notes on why other options were left out. For registry searches, you get matching entries with sources and code samples. Nothing is ever paid or changed.

Before you start

What you need

An AI app that supports MCP, like Claude Desktop, Claude Code, Cursor or Windsurf
Node.js 18.18 or newer if you use the local npx version

Good to know

This server is read-only and never spends money, but the text inside a 402 response comes from the server that sent it, so treat those fields as untrusted.

Install it with your AI

Add 402MCP payment helper to your AI, no technical skills needed

You don't install anything by hand. You copy one prompt, paste it into an AI that can work on your computer, and it checks, installs and connects the server for you, asking you when it needs something.

Sign in to get the install prompt

Members get a ready-made prompt that lets the Claude desktop app check 402MCP payment helper, install it and connect it for them, step by step. You don't need any technical skills: you copy, paste and answer a few questions. Your connected AI can also find and install any of the 4,609 MCP servers here for you.