Mppx Agent Skill

TypeScript SDK for the Payment HTTP Authentication Scheme. Handles 402 Payment Required flows with Tempo, Stripe, and other payment methods. Use when integrating payments or mppx into a client or server application.

4k tokens

context cost

the whole folder, loaded on every use

files

instructions only

copies elsewhere

how many repositories repackaged it

1529

stars on the repo

on the repository, not the skill itself

Install

one command, takes just this skill from the repository

npx skills add https://github.com/internet-court/internet-court-skill --skill mppx

What comes with it

10 838 bytes besides the instruction

LICENSE

The instruction itself

10 sections, as written by the author

mppx

TypeScript SDK for the "Payment" HTTP Authentication Scheme. Full 402 flow: challenge → credential → receipt.

What I can accomplish

Add 402 payment handling to a client with Fetch.polyfill or Fetch.from.
Protect HTTP routes with server-side MPP Challenges and Receipt responses.
Accept one-time Tempo stablecoin payments with tempo.charge.
Accept metered Tempo stablecoin payments with tempo.session.
Accept one-time card payments with stripe.charge.
Verify Credentials directly for custom transports or background workflows.
Wrap MCP clients and servers so tool calls can require payment.

Required inputs

Client integrations need a signing account and one or more client payment methods.
Server integrations need a recipient, currency, amount, and MPP_SECRET_KEY.
Tempo examples use chain ID 4217 unless a page explicitly covers Moderato testnet.
Stripe examples need a configured Stripe account and Shared Payment Token flow.
MCP integrations need the MCP client or server object to wrap.

Constraints

Keep MPP_SECRET_KEY server-side and out of logs.
Never commit private keys or wallet seeds.
Treat runtime 402 Challenges as authoritative for current payment terms.
Return id and opaque unchanged when responding to a Challenge.
Use USDC.e for Tempo bridged USDC examples, not generic USDC.

Client

import { Mppx, tempo } from 'mppx/client'

// Polyfills globalThis.fetch to handle 402 automatically
Mppx.create({
  methods: [tempo({ account })],
})

const res = await fetch('https://api.example.com/resource')

Without polyfilling:

const mppx = Mppx.create({
  methods: [tempo({ account })],
  polyfill: false,
})

const res = await mppx.fetch('https://api.example.com/resource')

Server

import { Mppx, Store, tempo } from 'mppx/server'
import { privateKeyToAccount } from 'viem/accounts'

const account = privateKeyToAccount('0x...')

const mppx = Mppx.create({
  methods: [
    tempo.charge({ currency: '0x...', recipient: '0x...' }),
    tempo.session({
      account,
      chainId: 4217,
      currency: '0x...',
      store: Store.memory(),
    }),
  ],
  secretKey: process.env.MPP_SECRET_KEY,
})

async function handler(request: Request): Promise<Response> {
  const result = await mppx.charge({ amount: '1.00' })(request)
  if (result.status === 402) return result.challenge
  return result.withReceipt(Response.json({ data: '...' }))
}

Methods

| Method | Intent | Description |

|---|---|---|

| tempo.charge | charge | One-time stablecoin payment (TIP-20 token transfer on Tempo) |

| tempo.session | session | Streaming payments via payment channels on Tempo |

| stripe.charge | charge | One-time payment via Stripe |

tempo() returns [tempo.charge, tempo.session] as a tuple using the current v2 Sessions implementation. Use tempo.charge() or tempo.session() individually if you only need one intent. Use tempo.sessionLegacy only for Legacy Sessions v1 compatibility.

Exports

| Path | Purpose |

|---|---|

| mppx | Core primitives (Challenge, Credential, Method, Receipt, PaymentRequest) |

| mppx/client | Mppx, tempo, stripe, session, Transport |

| mppx/server | Mppx, tempo, stripe, Transport, Store, NodeListener |

| mppx/hono | Hono middleware |

| mppx/express | Express middleware |

| mppx/nextjs | Next.js middleware |

| mppx/elysia | Elysia middleware |

CLI

mppx includes a CLI for making paid requests during development:

npx mppx account create        # create wallet
npx mppx mpp.dev/api/ping/paid # make paid request
npx mppx example.com -v        # verbose output

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How to use it

Copy the folder

Take internet-court/mppx from the repository into ~/.claude/skills for personal use, or into .claude/skills inside a project.

Check the name does not clash

The agent identifies a skill by the name field in its header. Two skills with the same name cannot sit side by side — one of them will be ignored.

Install what it needs

The instructions reference npx. Without those the skill loads but fails at the first command.