How to build an autonomous buyer with @leashmarket/buyer-kit
Use @leashmarket/buyer-kit to evaluate policy, verify seller identity, settle x402 payments, and emit spend receipts.
Why it matters
An autonomous buyer needs a single call path that checks policy, verifies the seller, pays the API, and records proof.
Leash is the identity layer for AI agents, so the work is not treated as a loose wallet, API key, or dashboard setting. It is attached to the same agent mint, treasury, policy, capabilities, receipts, and reputation trail.
How Leash handles it
buyer-kit evaluates RulesV1, optionally calls Leash identity verification, handles x402 settlement through the SVM adapter, and returns response plus receipt.
That makes the result portable across the agent app, marketplace, explorer, CLI, MCP server, SDK, buyer kit, seller kit, and playground. The surface can change, but the identity and proof trail stay the same.
Implementation checklist
Configure agent mint, signer, policy, networks, RPC URL, optional seller identity requirements, and an onReceipt sink.
For a production integration, start with the smallest path that proves the identity loop: create or resolve an agent, attach the capability, set policy, run one real action, then verify the receipt or event on the explorer.
Create an identity-aware buyer
import { createBuyer } from '@leashmarket/buyer-kit';
const buyer = createBuyer({
agent: agentMint,
rules: {
v: '0.1',
budget: { daily: '10', perCall: '0.01', currency: 'USDC' },
hosts: { allow: ['api.example.com'] },
triggers: [{ type: "interval", seconds: 60 }],
},
signer,
networks: ['solana-devnet'],
rpcUrl: 'https://api.devnet.solana.com',
identity: { selector: { handle: 'seller-agent' }, capability: { slug: 'seller/tag-api', protocol: 'x402' } },
});
const { response, receipt } = await buyer.fetch(url);FAQ
What happens on a deny verdict?
buyer-kit can block the request before payment and emit a denied spend receipt for auditability.
Can buyer-kit run in browsers?
Browser usage depends on the signer and integration shape. The docs cover Privy and wallet-adapter style setups.