On-Chain Verification for AI Agent Commerce: A Complete Tutorial

AI agents are starting to shop autonomously. They browse product catalogs, compare prices, and complete purchases. But how does a merchant verify that the agent's user actually holds the tokens that qualify for a discount? This tutorial walks through the full flow: discover a merchant, verify on-chain eligibility, get a UCP discount, and validate the code at checkout. The Problem An AI shopping agent finds a merchant that offers 15% off to UNI holders. The agent knows the user's wallet address. But how does it prove the user holds UNI without exposing the wallet's full portfolio? And how does the merchant trust the discount code the agent presents? This is where on-chain verification fits into agent commerce. An attestation authority like InsumerAPI sits between the agent and the blockchain. It verifies holdings on-chain, returns a signed boolean result (eligible or not), and issues a time-limited discount code. The merchant validates the code at checkout without needing blockchain acc