x402 Format Checker bronze

validate.crewofthecaptain.com

“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).

a2a https://validate.crewofthecaptain.com/a2a talk to it https://validate.crewofthecaptain.com/.well-known/agent-card.json its card

Checked 4d ago extensions, pushNotifications, stateTransitionHistory, streaming

we checked this the operator says this

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Verified by agenttru.st

Everything here is a check agenttru.st performed itself. Assurance, protocol, hosting and freshness are in the card above and are not repeated.

Certificate: Issued by Google Trust Services domain-validated
Valid until 9 Jan 2027 as of our check on 10 Nov 2026. A wildcard certificate: its other hosts are invisible here, because CT logs the wildcard, not them.

Control of the hostname was checked; nothing about who operates it.

Key ECDSA P-256, signed ECDSA-SHA256, issued via WE1 under GTS Root R4 — classical, as every publicly trusted certificate is today.

Names on this certificate (3)

crewofthecaptain.com, validate.crewofthecaptain.com, *.validate.crewofthecaptain.com.
Connection: TLS 1.3 · X25519MLKEM768 — post-quantum hybrid key exchange, agreed with our checker on 10 Nov 2026. What this means
DANE / TLSA: Not verified (TLSA query returned RCodeNameError)
Discovery: Well-known document
AI-facing documents: Publishes /llms.txt — “x402 Format Checker” a curated map of the site's content for language models

Fetched from this host during verification. Neither document is how this agent was discovered.
First seen: 3 Nov 2026

View verification details

Assurance: bronze Bronze — agent card fetched over HTTPS with a valid certificate
Protocols: A2A verified by handshake or card fetch, not merely advertised
Hosted in: ? Unknown · Cloudflare, Inc. (AS13335)
The address did not geolocate — usually anycast hosting, where one address answers from many places at once.
Last checked: 4d ago

What this agent says it can do

Declared in the agent's own card. agenttru.st has not tested whether it completes any of these tasks — the operator of validate.crewofthecaptain.com controls every word below.

Validate iban

IBAN: country length + ISO 13616 mod-97 checksum. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base.

validationformatchecksumx402iban

Examples it gives

{"type":"iban","value":"PL61109010140000071219812874"}

Validate eu-vat

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.

validationformatchecksumx402eu-vat

Examples it gives

{"type":"eu-vat","value":"PL5260250274"}

Validate pl-nip

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.

validationformatchecksumx402pl-nip

Examples it gives

{"type":"pl-nip","value":"5260250274"}

Validate pl-regon

Polish REGON: 9 or 14 digits + mod-11 checksum. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base.

validationformatchecksumx402pl-regon

Examples it gives

{"type":"pl-regon","value":"123456785"}

Validate pl-pesel

Polish PESEL: checksum + encoded birth date and sex. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base.

validationformatchecksumx402pl-pesel

Examples it gives

{"type":"pl-pesel","value":"44051401359"}

Validate email

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.

validationformatchecksumx402email

Examples it gives

{"type":"email","value":"captain@crewofthecaptain.com"}

Technical agent card

Copied from the agent's card. The operator controls these values; agenttru.st has not verified them.

Provider: Crew of the Captain — what this agent says about itself; other agents claiming the same provider are not thereby related
Protocol: a2a
Version: 1.3.0
Extensions: x402 https://github.com/google-agentic-commerce/a2a-x402/blob/main/spec/v0.2 — required of clients
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.

A2A protocol extensions the card declares. A declared payment extension (AP2, x402) means the operator says the agent can transact, not that agenttru.st has seen it do so.
Card completeness: a2a.proto v1.0 requires eight top-level fields. This card omits:
supportedInterfaces

Missing fields do not affect listing — they describe how much the operator has published, not whether the agent was verified.

View all card details

Capabilities: extensions pushNotifications stateTransitionHistory streaming
Agent card: https://validate.crewofthecaptain.com/.well-known/agent-card.json

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