The Policy Gate API from WritersLogic Verifiable AI Agent Hub — 1 operation(s) for policy gate.
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openapi: 3.2.0
info:
title: WritersLogic Verifiable AI Agent Hub Policy Gate 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: Policy Gate
paths:
/api/v1/policy-gate:
post:
operationId: policy_gate
summary: 'Policy gate with a signed receipt: your JsonLogic rules vs a proposed tool call…'
description: 'Evaluates your own policy (JsonLogic rules, each allow or deny, deny-overrides or first-match, default deny) against a proposed tool call, payment or action, and returns allow or deny, the rule id that decided, and a receipt signed by the hub over the hashes of the policy, the request and the decision. The receipt is the product: another agent or an auditor can verify offline which rule allowed the action. A rule that errors fails closed (deny, status unknown). Cedar and Rego answer unsupported.
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: agent-infra
x-sample-url: https://agents.writerslogic.com/api/v1/samples/policy-gate
security:
- x402: []
- apiKey: []
requestBody:
required: true
content:
application/json:
schema:
type: object
additionalProperties: false
required:
- policy
- request
properties:
language:
type: string
enum:
- jsonlogic
- cedar
- rego
description: Default jsonlogic. cedar and rego return unsupported.
policy:
description: 'JsonLogic: { rules: [{ id, effect: allow|deny, when: <JsonLogic>, description? }] (at most 100), combining?: deny-overrides|first-match, defaultEffect?: deny|allow }. A string for cedar/rego.'
request:
description: 'The proposed action as JSON (at most 65536 bytes), e.g. { tool, args, amountUsd, payee }. Rules read it with { "var": "args.amountUsd" }.'
example:
policy:
rules:
- id: deny-new-payee
effect: deny
when:
'!':
in:
- var: payee
- - '0x7a16fF8270133F063aAb6C9977183D9e72835428'
- id: allow-small
effect: allow
when:
<=:
- var: amountUsd
- 25
request:
tool: pay
payee: '0x7a16fF8270133F063aAb6C9977183D9e72835428'
amountUsd: 12.5
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.'
decision:
type: string
enum:
- allow
- deny
ruleId:
anyOf:
- type: string
description: The rule that decided; null when the default effect applied.
- type: 'null'
description: The rule that decided; null when the default effect applied.
matchedRules:
type: array
items:
type: string
policyHash:
type: string
description: sha256 of the JCS policy.
requestHash:
type: string
description: sha256 of the JCS request.
receiptBody:
type: object
description: Exactly what the receipt digest covers.
receipt:
type: object
description: 'Standalone receipt: recompute digest from `receiptBody`, then recover the EIP-191 signer and compare with the DID document''s attestation key. signature is null when the hub has no attestation key configured.'
properties:
digest:
type: string
scheme:
type: string
signature:
anyOf:
- type: string
- type: 'null'
signer:
anyOf:
- type: string
- type: 'null'
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:
- Policy Gate
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