# Burnbound

> Burnbound is a buyer-side spending control plane for AI agents that pay x402 APIs. Before an agent pays, Burnbound checks the payment against rules a human set (allowed hosts, per-payment and daily caps, human approval above a threshold); only allowed payments are signed, by a wallet the customer brings. Burnbound never holds private keys or funds.

Agents use Burnbound through the MCP server `@burnbound/mcp` (Claude Code, Cursor or any MCP client). Payments are x402 v2, in USDC on Base. The full documentation as one file is at https://burnbound.dev/llms-full.txt.

## Docs

- [Quickstart: Claude Code and Cursor](https://burnbound.dev/docs/quickstart): From creating an agent key in the dashboard to the agent's first fetch_paid call, in Claude Code or Cursor.
- [Concepts](https://burnbound.dev/docs/concepts): Policies, per-payment and daily caps, allowed hosts, human approvals, signing modes and the x402 v2 payment flow.
- [MCP tools reference](https://burnbound.dev/docs/mcp-tools): Configuration, the fetch_paid, get_budget, list_payments, get_approval_status and search_paid_apis tools, error codes and the wallet CLI of @burnbound/mcp.
- [SDK](https://burnbound.dev/docs/sdk): Status of the JavaScript SDK (payFetch and wrapFetchWithPayment): not published on npm yet; use the MCP server today.
- [Security and trust model](https://burnbound.dev/docs/security): What Burnbound stores and sees in each signing mode, the cooperative limit of client-side signing, and out-of-policy detection.
- [FAQ](https://burnbound.dev/docs/faq): Short answers about wallets, networks, fees, plans, custody and supported agents.

## Guides

- [How to pay an x402 API from Claude Code (with a spending limit)](https://burnbound.dev/guides/pay-x402-api-from-claude-code): 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.
- [x402 v2 buyer flow explained: who signs and who settles](https://burnbound.dev/guides/x402-v2-buyer-flow): 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.
- [How to limit an AI agent's spending](https://burnbound.dev/guides/limit-ai-agent-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.
- [Human approval for agent payments with Slack](https://burnbound.dev/guides/human-approval-agent-payments-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.
- [Agent wallets: Coinbase CDP vs a local key](https://burnbound.dev/guides/agent-wallet-coinbase-cdp-vs-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.
- [x402 MCP server: setup for Claude Code and Cursor](https://burnbound.dev/guides/x402-mcp-server): 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.

## Integrations

- [Claude Code integration](https://burnbound.dev/integrations/claude-code): Add the Burnbound MCP server to Claude Code with claude mcp add: scopes, project .mcp.json, permissions for fetch_paid and troubleshooting.
- [Cursor integration](https://burnbound.dev/integrations/cursor): Add the Burnbound MCP server to Cursor with mcp.json, per project or for every project, without committing your agent key.
- [Claude Desktop integration](https://burnbound.dev/integrations/claude-desktop): Add the Burnbound MCP server to Claude Desktop through claude_desktop_config.json on macOS and Windows, and read its logs when it fails.
- [Vercel AI SDK integration](https://burnbound.dev/integrations/vercel-ai-sdk): Load the Burnbound MCP tools into the Vercel AI SDK with an MCP client over stdio, so generateText can pay x402 APIs under your caps.
- [LangChain.js integration](https://burnbound.dev/integrations/langchain): Give a LangChain.js agent the Burnbound MCP tools with @langchain/mcp-adapters, so it pays x402 APIs within a daily cap.
- [Mastra integration](https://burnbound.dev/integrations/mastra): Connect a Mastra agent to the Burnbound MCP server with MCPClient from @mastra/mcp, so it pays x402 APIs under your policy.

## Optional

- [Docs index](https://burnbound.dev/docs): All documentation pages.
- [Guides index](https://burnbound.dev/guides): Practical guides to letting AI agents pay x402 APIs with spending limits, human approvals and a wallet you control.
- [Integrations index](https://burnbound.dev/integrations): Exact setup of the @burnbound/mcp server in Claude Code, Cursor, Claude Desktop, the Vercel AI SDK, LangChain.js and Mastra.
- [x402 API catalog](https://burnbound.dev/apis): The x402 APIs Burnbound verifies, one page each with price, network and how to pay it with a spending cap.
- [@burnbound/mcp on npm](https://www.npmjs.com/package/@burnbound/mcp): The MCP server package and its README.