Burnbound

Guides: paying x402 APIs from AI agents

Practical guides to letting AI agents pay x402 APIs with spending limits, human approvals and a wallet you control.

  1. How to pay an x402 API from Claude Code (with a spending limit)

    Step by step: give Claude Code a daily cap and a list of allowed hosts, then let it pay a real x402 API such as Exa search in USDC.

  2. x402 v2 buyer flow explained: who signs and who settles

    The x402 v2 payment flow from the buyer's side: the 402 challenge, the EIP-3009 signature, the retry, and why the buyer never calls settle.

  3. How to limit an AI agent's spending

    The controls that bound what an AI agent can pay: per-payment and daily caps, allowed hosts, per-call limits, human approval and wallet balance.

  4. Human approval for agent payments with Slack

    Make an AI agent wait for a human above a USD threshold, get a Slack message for each payment, and let the agent retry safely once approved.

  5. Agent wallets: Coinbase CDP vs a local key

    Where the key lives, who can sign and what an agent with shell access can do, for a Coinbase CDP wallet and a key on your own machine.

  6. x402 MCP server: setup for Claude Code and Cursor

    What an x402 MCP server does, the five tools of @burnbound/mcp, and how to install it in Claude Code and Cursor with your agent key.