The Schema Witness API from WritersLogic Verifiable AI Agent Hub — 1 operation(s) for schema witness.
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openapi: 3.2.0
info:
title: WritersLogic Verifiable AI Agent Hub Schema Witness 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: Schema Witness
paths:
/api/v1/schema-witness:
post:
operationId: schema_witness
summary: One valid and one invalid example for each constraint in a JSON Schema
description: 'Walks a caller-supplied JSON Schema 2020-12 and, for every constraint keyword (type, enum, const, minimum, maximum, exclusiveMinimum, exclusiveMaximum, multipleOf, minLength, maxLength, pattern, format, minItems, maxItems, uniqueItems, required, minProperties, maxProperties, additionalProperties false, dependentRequired), returns the JSON pointer of the constraint, an example that satisfies it and a boundary example that violates it. Every pair is verified by running both examples through the interpreter against a schema holding only that constraint, so each valid example passes and each invalid example fails exactly that rule. For agents that need test inputs or few-shot examples for a tool schema. Constraints inside combinators are included; $ref targets are visited under $defs. Constraints it cannot build a verified pair for (exotic patterns, huge limits) are listed as unresolved, never guessed.
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: developer
x-sample-url: https://agents.writerslogic.com/api/v1/samples/schema-witness
security:
- x402: []
- apiKey: []
requestBody:
required: true
content:
application/json:
schema:
type: object
additionalProperties: false
required:
- schema
properties:
schema:
description: The schema to generate examples for. Full JSON Schema 2020-12 (local $ref only).
maxConstraints:
type: integer
minimum: 1
maximum: 100
description: Stop after this many constraints (default 100).
example:
schema:
type: object
required:
- name
- age
properties:
name:
type: string
minLength: 2
maxLength: 5
age:
type: integer
minimum: 0
maximum: 150
additionalProperties: false
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.'
pairs:
type: array
items:
type: object
properties:
path:
type: string
description: JSON pointer of the constraint keyword inside the schema.
keyword:
type: string
constraint:
description: The keyword's value.
valid:
description: An instance that satisfies the constraint (at the boundary where one exists).
invalid:
description: An instance that violates only this constraint.
unresolved:
type: array
items:
type: object
properties:
path:
type: string
keyword:
type: string
reason:
type: string
constraintCount:
type: integer
truncated:
type: boolean
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:
- Schema Witness
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