The Sentinel Values API from WritersLogic Verifiable AI Agent Hub — 1 operation(s) for sentinel values.
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openapi: 3.2.0
info:
title: WritersLogic Verifiable AI Agent Hub Sentinel Values 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: Sentinel Values
paths:
/api/v1/sentinel-values:
post:
operationId: sentinel_values
summary: 'Placeholder values hiding as data: caller-declared sentinels and likely…'
description: 'Scans columns of values for sentinels. Values you declare in a dictionary (for example -1 means unknown in column age) are reported as asserted hits with their row paths. Other values that look like missing-data markers are reported separately as candidates, never asserted: the pandas default NA strings, spreadsheet error values, whitespace-only text, placeholder words, zero and epoch dates, fixed-width integer limits, -1 in an otherwise non-negative column, runs of 9s above or below every other value, and a numeric value repeated at least 3 times that lies beyond 3 interquartile ranges of the rest. For agents about to average, sum, join or load a column. It cannot know what a value means: a candidate may be real data, and 0 is never flagged.
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/sentinel-values
security:
- x402: []
- apiKey: []
requestBody:
required: true
content:
application/json:
schema:
type: object
additionalProperties: false
required:
- columns
properties:
columns:
type: array
minItems: 1
maxItems: 50
items:
type: object
additionalProperties: false
required:
- name
- values
properties:
name:
type: string
maxLength: 100
values:
type: array
maxItems: 2000
items:
description: 'A cell: string, number, boolean or null.'
dictionary:
type: array
maxItems: 100
items:
type: object
additionalProperties: false
required:
- value
properties:
column:
type: string
maxLength: 100
description: Limit the entry to this column; omit for all columns.
value:
description: The sentinel value (string, number or boolean); matched by type and value.
meaning:
type: string
maxLength: 200
description: Values you know are sentinels.
example:
columns:
- name: age
values:
- 34
- 29
- -1
- 41
- -1
- 52
- 38
- 27
- 45
- 33
- 30
- 36
- name: joined
values:
- '2021-03-04'
- '1970-01-01'
- '2022-07-19'
- N/A
dictionary:
- column: age
value: -1
meaning: unknown
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.'
columns:
type: array
items:
type: object
properties:
name:
type: string
valueCount:
type: integer
nullCount:
type: integer
assertedHits:
type: array
items:
type: object
properties:
value:
description: Dictionary value
meaning:
anyOf:
- type: string
- type: 'null'
count:
type: integer
share:
type: number
firstIndexes:
type: array
items:
type: integer
candidates:
type: array
items:
type: object
properties:
value:
description: Candidate value
count:
type: integer
share:
type: number
asserted:
type: boolean
description: 'Always false: candidates are never asserted.'
firstIndexes:
type: array
items:
type: integer
reasons:
type: array
items:
type: object
properties:
rule:
type: string
source:
type: string
kind:
type: string
enum:
- documented
- convention
- arithmetic
- statistical
note:
type: string
assertedHitCount:
type: integer
candidateCount:
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:
- Sentinel Values
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