The Checksum API from WritersLogic Verifiable AI Agent Hub — 1 operation(s) for checksum.
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openapi: 3.2.0
info:
title: WritersLogic Verifiable AI Agent Hub Checksum API
version: 2.0.0
description: Pay-per-call agents settled in USDC on Base via x402. Every response carries a signed provenance envelope.
contact:
name: WritersLogic
url: https://writerslogic.com/agents
email: agents@writerslogic.com
servers:
- url: https://agents.writerslogic.com
tags:
- name: Checksum
paths:
/api/v1/checksum:
post:
operationId: checksum
summary: 'Identifier check digits: IBAN, ISBN, GTIN, VIN, ISIN, LEI and more, in a batch'
description: 'Validates the format and check digit of up to 100 identifiers per call, for an agent about to put an IBAN, ISBN, GTIN/EAN/UPC, container number, VIN, ISIN, CUSIP, SEDOL, LEI, IMO number, BIC or Luhn number into a payment, order or record. Each item is {kind, value}; with kind omitted the engine proposes candidate kinds and answers unknown if two kinds both validate. Reports the normalized form (lower case and spaces accepted) and the expected vs actual check digit. It does not check that the identifier exists, is registered or belongs to anyone, and it does not apply national BBAN check digits inside an IBAN.
Price: 0.005 USDC on Base (x402).'
x-x402-price-usdc: '0.005'
x-x402-amount: '5000'
x-payment-info:
protocols:
- x402
price:
mode: fixed
currency: USD
amount: '0.005'
x-audience: business
x-sample-url: https://agents.writerslogic.com/api/v1/samples/checksum
security:
- x402: []
- apiKey: []
requestBody:
required: true
content:
application/json:
schema:
type: object
additionalProperties: false
required:
- items
properties:
items:
type: array
minItems: 1
maxItems: 100
items:
type: object
required:
- value
properties:
kind:
type: string
enum:
- iban
- iso6346
- gtin
- isbn10
- isbn13
- issn
- vin
- isin
- cusip
- sedol
- lei
- imo
- bic
- luhn
description: iban, iso6346 (container), gtin (8/12/13/14), isbn10, isbn13, issn, vin, isin, cusip, sedol, lei, imo, bic (ISO 9362 format only), luhn. Omit to auto-detect (luhn is never auto-detected).
value:
type: string
minLength: 1
maxLength: 64
strict:
type: boolean
description: 'VIN only: report a check-digit mismatch as fail even outside US/Canada/Mexico, where position 9 is not mandatory.'
example:
items:
- kind: iban
value: gb82 west 1234 5698 7654 32
- value: 978-0-306-40615-7
- kind: vin
value: 1G4AH59H45G118341
responses:
'200':
description: Paid result with provenance
content:
application/json:
schema:
type: object
properties:
data:
type: object
properties:
status:
type: string
enum:
- pass
- fail
- unknown
- unsupported
description: 'pass: every rule held. fail: a rule was violated (see witnesses). unknown: the input lacks the evidence to decide. unsupported: outside what this engine covers. Missing evidence is never a pass.'
results:
type: array
items:
type: object
properties:
index:
type: integer
kind:
anyOf:
- type: string
enum:
- iban
- iso6346
- gtin
- isbn10
- isbn13
- issn
- vin
- isin
- cusip
- sedol
- lei
- imo
- bic
- luhn
- type: 'null'
candidates:
type: array
items:
type: string
description: Kinds the value could be. More than one that validates -> status unknown.
normalized:
anyOf:
- type: string
- type: 'null'
status:
type: string
enum:
- pass
- fail
- unknown
- unsupported
notes:
type: array
items:
type: string
description: Normalizations applied (upper-casing, separators removed).
checkDigit:
anyOf:
- type: object
properties:
expected:
type: string
actual:
type: string
- type: 'null'
info:
description: 'Kind-specific facts: IBAN country and BBAN structure, ISBN registration group, VIN WMI, BIC parts.'
counts:
type: object
description: Items per status.
properties:
pass:
type: integer
fail:
type: integer
unknown:
type: integer
unsupported:
type: integer
witnesses:
type: array
items:
type: object
properties:
ruleId:
type: string
detail:
type: string
path:
type: string
description: JSON pointer or dotted path into the input.
offset:
type: integer
index:
type: integer
expected:
description: What the rule required.
actual:
description: What the input had.
versions:
type: object
description: Every semantic dependency of this answer (engine, tables and their as-of dates, tokenizer, calendar, rounding profile).
limits:
type: array
items:
type: string
deterministic:
type: boolean
description: 'Always true: pure code, no model.'
_provenance:
type: object
description: C2PA-aligned manifest and W3C VC 2.0 (eddsa-jcs-2022) issued by the hub DID; verify at POST /api/v1/verify-provenance
required:
- data
- _provenance
'400':
description: Invalid request (no payment consumed)
content:
application/json:
schema:
type: object
properties:
error:
type: string
code:
type: string
'401':
description: Invalid X-API-KEY
content:
application/json:
schema:
type: object
properties:
error:
type: string
code:
type: string
'402':
description: Payment required or invalid
content:
application/json:
schema:
type: object
description: x402 v2 PaymentRequired (also base64 in the PAYMENT-REQUIRED header)
properties:
x402Version:
type: integer
error:
type: string
code:
type: string
resource:
type: object
accepts:
type: array
items:
type: object
extensions:
type: object
'502':
description: Upstream failure; the payment is released or not settled
content:
application/json:
schema:
type: object
properties:
error:
type: string
code:
type: string
tags:
- Checksum
components:
securitySchemes:
x402:
type: apiKey
in: header
name: PAYMENT-SIGNATURE
description: x402 v2 payment payload (base64) sent after a 402 challenge
apiKey:
type: apiKey
in: header
name: X-API-KEY