Getting Started with Agent Payments — Actually Spend Your Credits

You registered on minia2a and got 500 free credits. Now what?

This guide gets you from "I have credits" to "I just called a paid API and got a result" in under 2 minutes. No blockchain knowledge required. No wallet setup. Just HTTP.

The 60-Second Version

curl -s -X POST https://minia2a.uk/api/v1/register-simple \
  -H "Content-Type: application/json" \
  -d '{"name":"my-agent"}'

curl -s "https://minia2a.uk/x402/time" \
  -H "X-Wallet: YOUR_WALLET_ADDRESS"

curl -s "https://minia2a.uk/api/v1/credits?wallet=YOUR_WALLET_ADDRESS"

The Problem: Why Your Agent Won't Spend Credits

If you're using Claude Code or Codex, you may have noticed: your agent wants to call a paid API, but it stops before paying. This isn't a bug — it's a missing spending policy.

Agent frameworks default to "ask the human before spending money." If you're not watching, the agent stalls. This is the agent purchasing loop problem we wrote about earlier today.

The fix for Claude Code users today:

Method 1: Tell Claude Code to spend (prompt-level)

You have permission to call paid APIs up to $1/call and $5/day.
When you see HTTP 402 with a price under $1, pay it automatically.
My wallet: YOUR_WALLET_ADDRESS
Use it in the X-Wallet header on all x402 calls.

Add this to your CLAUDE.md or say it at the start of a session. Claude Code can sign and send USDC transactions when given explicit permission.

Method 2: Use .agent-budget (the standard we're proposing)

Create ~/.agent-budget:

{"daily_limit_usdc": 5, "max_per_call_usdc": 1}

This is a proposed standard — framework support is coming. For now, Method 1 works today.

curl: The Universal Agent Payment Client

You don't need an agent framework to spend credits. curl works everywhere:

Trial mode (no wallet, no credits — first 5 calls per endpoint)

curl -s "https://minia2a.uk/x402/crypto-price?symbol=ETH"

Credit mode (with registered wallet)

curl -s "https://minia2a.uk/x402/crypto-price?symbol=ETH" \
  -H "X-Wallet: 0xYOUR_WALLET"

Bearer token mode (for API key-style auth)

curl -s "https://minia2a.uk/x402/crypto-price?symbol=ETH" \
  -H "Authorization: Bearer 0xYOUR_WALLET"

All three work. The X-Wallet header is the simplest.

Top 10 Endpoints Your Agent Will Actually Use

Based on real usage data from 12,427 trials — these are what agents actually call:

Python: Agent Payments in 4 Lines

import requests, os

WALLET = os.getenv("MINIA2A_WALLET")  # your registered wallet
r = requests.get("https://minia2a.uk/x402/crypto-price",
                 headers={"X-Wallet": WALLET},
                 params={"symbol": "ETH"})
print(r.json())
# {"ok":true,"result":{"symbol":"ETH","price_usd":..."},"credits_remaining":499}

Set MINIA2A_WALLET as an environment variable and every call just works. Same pattern for Node.js, Go, Rust — any HTTP client.

What Happens When Credits Run Out?

When credits_remaining hits 0, you have options:

1. Buy more credits — USDC on Base, 1 USDC = 200 credits. Check /buy.html.
2. Pay per call with USDC — The endpoint returns HTTP 402 with a price. Your agent signs the transaction directly. No credits needed.
3. Use other endpoints — Each endpoint has its own 5-free-trial counter per IP.

Why Can't I Just Use an API Key?

You can — that's the point. x402 doesn't replace API keys; it removes the need for them. When your agent calls 20 different services, it shouldn't manage 20 different API keys, rate limits, and billing dashboards. One wallet. One payment rail. Any endpoint.

This matters most when:

• Your agent discovers a new service mid-task — no signup, just pay and use
• You're composing 5+ services per task — wallet-based auth scales, API keys don't
• You're building for other people's agents — they bring their own payment

Troubleshooting

"I get a 402 error"

You're out of trials and not sending a wallet. Either register for credits or use X-Wallet header.

"My credits aren't being deducted"

The first 5 calls per endpoint per IP are free trials. Credits only deduct after trial exhaustion. Check credits_remaining in the response.

"My agent stops before paying"

This is the agent purchasing loop problem. Tell your agent it has spending permission (see Method 1 above). We're working on the .agent-budget standard to fix this permanently.

"I lost my wallet address"

Check your agent's environment variables or CLAUDE.md. The wallet is a standard Ethereum address (0x...). If you registered with /api/v1/register-simple, the wallet was in the response — hopefully you saved it!

Tags: x402, getting-started, agent-payments, tutorial, credits, claude-code, codex