Give Your AI Agent a Credit Line in 5 Minutes

This tutorial walks you through giving an AI agent its own credit line with Mithril. By the end, your agent will be able to pay for any x402 service autonomously.

Prerequisites

Step 1: Get Your API Key

After signing up, navigate to the dashboard and generate an API key. This key authenticates your agent with the Mithril API.

Store it as an environment variable:

export MITHRIL_API_KEY="mk_live_..."

Step 2: Install the SDK

TypeScript:

npm install @mithril/sdk

Python:

pip install mithril

Step 3: Create a Wallet

Each agent should have its own wallet. Create one via the SDK:

import Mithril from "@mithril/sdk"

const m = new Mithril({
  apiKey: process.env.MITHRIL_API_KEY,
})

// Your default wallet is created automatically
const wallets = await m.wallets.list()
console.log(wallets[0].id) // "wal_..."

Step 4: Set Spending Limits

Configure daily and per-transaction limits for safety:

// Check your spending power
const power = await m.spendingPower()
console.log(power.available) // "100.00" USDC

Step 5: Make Your First x402 Payment

Now the magic — call any x402 service and Mithril handles payment automatically:

const result = await m.pay({
  url: "https://api.exa.ai/search",
  method: "POST",
  body: JSON.stringify({
    query: "best AI agent frameworks 2026",
    numResults: 10,
  }),
})

console.log(result.data) // Search results!

That's it. The SDK detected the 402 response, paid with USDC on-chain, and retried the request — all transparently.

Step 6: Monitor Spending

Check your agent's transactions:

const transactions = await m.wallets.transactions(walletId)
transactions.forEach(tx => {
  console.log(`${tx.service}: ${tx.amount} USDC`)
})

Alternative: SKILL.md (No SDK Required)

If you're using Claude Code, Codex, or any MCP-compatible agent, you can skip the SDK entirely. Just point your agent to:

https://trymithril.com/SKILL.md

The agent reads the SKILL.md and gains full API access — including x402 payments — without any code integration.

Next Steps