{"service":"agenttoll.dev","endpoint":"https://agenttoll.dev/paid/academic/isbn","method":"POST","protocol":"x402","price_usd":"0.02","network":"eip155:8453","facilitator":"https://api.cdp.coinbase.com/platform/v2/x402","message":"This is an x402-paid API endpoint. Send a POST request with JSON to receive the 402 payment challenge, then retry with a signed payment.","tool":{"name":"isbn_book_lookup","description":"Book metadata by ISBN — title, authors, publisher, page count, cover URL via Open Library.","buyer_value":"Pay $0.02 for Book metadata by ISBN — title, authors, publisher, page count, cover URL via Open Library.","input":{"isbn":"string ISBN-10 or ISBN-13"},"example":{"isbn":"9780140328721"},"sample_output":"JSON with source-backed fields, response metadata, and decision/readout fields where the endpoint is a brief.","discovery_queries":["isbn book lookup","isbn book lookup x402","paid MCP tool","paid data API for AI agents"],"docs":"https://agenttoll.dev/tools/isbn_book_lookup"}}