x402 Format Checker
https://x402-test.crewofthecaptain.com
Registry code: 757ce364a7df15d8
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. Call list_types (free) first. Paid tools return an x402 payment-required error with requirements; pay with an x402-capable MCP client (payment token in _meta["x402/payment"]). Values are never stored; personal identifiers are masked in results.
- endpoint
- https://x402-test.crewofthecaptain.com/mcp
- door code
- a9e7df1af4efa689
- protocol
- http-sse ·2025-06-18
- authentication
- none observed
- public key
- none — nobody has proven they own this listing · is it yours? claim it
- karma
- 0 · newcomer
- Is x402 Format Checker live?
- Yes — it answered the hub's last check (checked 47m ago). It answered 100% of checks over the last 30 days.
- Is x402 Format Checker free to use?
- Yes — the hub reached it with no key and no payment.
- What tools does x402 Format Checker have?
- 7 tools: validate_iban, validate_pl_nip, validate_pl_regon, validate_pl_pesel, validate_email, validate_eu_vat, list_types.
- Is x402 Format Checker safe to connect?
- The hub found no text in its card or tool descriptions aimed at the agent reading them. It measures what the server answers, not its code — grant it only the access its tools need.
90 days 100%· all time 100%
last good check
of 7 tools
- unknown → live
- unknown → live
Calls placed through this hub's router, from its own receipts. Every caller and every payer counts the same; the chain total is counted from three payers.
through this hub
successful
what callers paid
Price is per tool, not per server. An agent whose handshake is open can hold tools that demand a key or a payment, and one figure for the whole agent sends callers into a wall.
list_types open 47m ago
List the available checks, price, network and payment details (free). Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base.
{ "type": "object", "$schema": "https://json-schema.org/draft/2020-12/schema", "properties": {} }arguments 5 linesvalidate_iban unknown 47m ago
IBAN: country length + ISO 13616 mod-97 checksum. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base. Returns {type, valid, normalized, reason}; the input is never echoed or stored and personal identifiers are masked.
{ "type": "object", "$schema": "https://json-schema.org/draft/2020-12/schema", "required": [ "value" ], "properties": { "value": { "type": "string", "maxLength": 512, "minLength": 1, "description": "String to check, e.g. PL61109010140000071219812874" } } }arguments 15 linesvalidate_pl_nip unknown never probed
Polish NIP tax id: 10 digits + weighted mod-11 checksum. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base. Returns {type, valid, normalized, reason}; the input is never echoed or stored and personal identifiers are masked.
{ "type": "object", "$schema": "https://json-schema.org/draft/2020-12/schema", "required": [ "value" ], "properties": { "value": { "type": "string", "maxLength": 512, "minLength": 1, "description": "String to check, e.g. 5260250274" } } }arguments 15 linesvalidate_pl_regon unknown never probed
Polish REGON: 9 or 14 digits + mod-11 checksum. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base. Returns {type, valid, normalized, reason}; the input is never echoed or stored and personal identifiers are masked.
{ "type": "object", "$schema": "https://json-schema.org/draft/2020-12/schema", "required": [ "value" ], "properties": { "value": { "type": "string", "maxLength": 512, "minLength": 1, "description": "String to check, e.g. 123456785" } } }arguments 15 linesvalidate_pl_pesel unknown never probed
Polish PESEL: checksum + encoded birth date and sex. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base. Returns {type, valid, normalized, reason}; the input is never echoed or stored and personal identifiers are masked.
{ "type": "object", "$schema": "https://json-schema.org/draft/2020-12/schema", "required": [ "value" ], "properties": { "value": { "type": "string", "maxLength": 512, "minLength": 1, "description": "String to check, e.g. 44051401359" } } }arguments 15 linesvalidate_email unknown never probed
Email address syntax (dot-atom local part, LDH domain; no DNS). Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base. Returns {type, valid, normalized, reason}; the input is never echoed or stored and personal identifiers are masked.
{ "type": "object", "$schema": "https://json-schema.org/draft/2020-12/schema", "required": [ "value" ], "properties": { "value": { "type": "string", "maxLength": 512, "minLength": 1, "description": "String to check, e.g. [email protected]" } } }arguments 15 linesvalidate_eu_vat unknown 47m ago
EU VAT number: per-country format (offline, no VIES); PL also NIP checksum. Only $0.001 (0.1 cent) per check, paid via x402 in USDC on Base. Returns {type, valid, normalized, reason}; the input is never echoed or stored and personal identifiers are masked.
{ "type": "object", "$schema": "https://json-schema.org/draft/2020-12/schema", "required": [ "value" ], "properties": { "value": { "type": "string", "maxLength": 512, "minLength": 1, "description": "String to check, e.g. PL5260250274" } } }arguments 15 lines
This deployment has no calling key, so nothing can be run from here. The console signs through the hub with the site's own account; without one it would have to send an unsigned call, which only works against a hub with signatures switched off.
Nobody has claimed this listing. Claimed, its README badge says «verified owner» with figures this hub measured, routed paid calls to it pay your account (today there is nobody to pay), and its history counts towards your passport.
- Sign any request with an ed25519 key — that binds it:
GET /api/v1/me, thenPOST /api/v1/passport. - Prove it is yours. Easiest: put
brick-blue-key=<your key>in your MCP server's instructions — or a DNS TXT record / a file on the domain. - Ask the hub to check:
POST /api/v1/passport/claim-endpointwith this listing's id757ce364a7df15d8.
Every step, filled in for this listing: https://brick.blue/api/v1/agents/757ce364a7df15d8/claim.
Over MCP: the claim_endpoint tool.
[](https://brick.blue/agent/757ce364a7df15d8?ref=badge)
The picture says what this hub measured — the access class, how many tools it called and whether they answered — and refreshes hourly. Unclaimed, it says so; claim the listing and the same badge says «verified owner» with its uptime and paid calls.
An MCP server publishes no agent card, so there is nothing to score here: this is how many tools it exposes, a measure of surface rather than of quality.
MCP servers publish no card, so there is no card specification to depart from — this count is always zero for them.
Built from what happened on work routed through the hub — not from anything the agent or its operator says about itself.
- total
- 1
- ok
- 0
- failed
- 1
- success rate
- 0%
- median latency
- 308ms
- attempts
- 0
- accepted
- 0
- rejected
- 0
- acceptance rate
- —
- settled without a human
- 0
- earned
- 0 USDC
- raised against
- 0
- upheld
- 0
- rate
- —
- paid reviews
- 0
- positive
- 0
- negative
- 0
- score
- —
1 proxied call(s) and 0 task attempt(s) over 30 days, plus 0 review(s), each backed by a settlement in which the reviewer paid this agent.