{"protocolVersion":"0.3.0","name":"x402 Format Checker","description":"Format and checksum validation for IBAN, EU VAT, Polish NIP/REGON/PESEL and email, pay-per-call via x402. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base. Send message/send with a data part {\"type\": \"<skill id>\", \"value\": \"...\"}; the agent answers with an x402 payment-required task, then re-send the same data part with the signed payment in message.metadata (stateless: nothing is stored).","url":"https://x402-test.crewofthecaptain.com/a2a","preferredTransport":"JSONRPC","version":"1.2.0","provider":{"organization":"Crew of the Captain","url":"https://crewofthecaptain.com"},"documentationUrl":"https://x402-test.crewofthecaptain.com/llms.txt","capabilities":{"streaming":false,"pushNotifications":false,"stateTransitionHistory":false,"extensions":[{"uri":"https://github.com/google-agentic-commerce/a2a-x402/blob/main/spec/v0.2","description":"Supports payments using the x402 protocol for on-chain settlement. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base.","required":true}]},"defaultInputModes":["application/json"],"defaultOutputModes":["application/json"],"skills":[{"id":"iban","name":"Validate iban","description":"IBAN: country length + ISO 13616 mod-97 checksum. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base.","tags":["validation","format","checksum","x402","iban"],"examples":["{\"type\":\"iban\",\"value\":\"PL61109010140000071219812874\"}"],"inputModes":["application/json"],"outputModes":["application/json"]},{"id":"eu-vat","name":"Validate eu-vat","description":"EU VAT number: per-country format (offline, no VIES); PL also NIP checksum. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base.","tags":["validation","format","checksum","x402","eu-vat"],"examples":["{\"type\":\"eu-vat\",\"value\":\"PL5260250274\"}"],"inputModes":["application/json"],"outputModes":["application/json"]},{"id":"pl-nip","name":"Validate pl-nip","description":"Polish NIP tax id: 10 digits + weighted mod-11 checksum. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base.","tags":["validation","format","checksum","x402","pl-nip"],"examples":["{\"type\":\"pl-nip\",\"value\":\"5260250274\"}"],"inputModes":["application/json"],"outputModes":["application/json"]},{"id":"pl-regon","name":"Validate pl-regon","description":"Polish REGON: 9 or 14 digits + mod-11 checksum. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base.","tags":["validation","format","checksum","x402","pl-regon"],"examples":["{\"type\":\"pl-regon\",\"value\":\"123456785\"}"],"inputModes":["application/json"],"outputModes":["application/json"]},{"id":"pl-pesel","name":"Validate pl-pesel","description":"Polish PESEL: checksum + encoded birth date and sex. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base.","tags":["validation","format","checksum","x402","pl-pesel"],"examples":["{\"type\":\"pl-pesel\",\"value\":\"44051401359\"}"],"inputModes":["application/json"],"outputModes":["application/json"]},{"id":"email","name":"Validate email","description":"Email address syntax (dot-atom local part, LDH domain; no DNS). Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base.","tags":["validation","format","checksum","x402","email"],"examples":["{\"type\":\"email\",\"value\":\"captain@crewofthecaptain.com\"}"],"inputModes":["application/json"],"outputModes":["application/json"]}]}