WritersLogic Verifiable AI Agent Hub Citation Span API
The Citation Span API from WritersLogic Verifiable AI Agent Hub — 1 operation(s) for citation span.
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curl "https://apis.io/api/v1/apis/writerslogic-com:writerslogic-com-citation-span-api"
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OpenAPI Specification
openapi: 3.2.0
info:
title: WritersLogic Verifiable AI Agent Hub Citation Span 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: Citation Span
paths:
/api/v1/citation-span:
post:
operationId: citation_span
summary: Locate quoted text in a source with exact offsets, or classify it as…
description: 'Finds each quote an agent attributes to a source text and returns where it sits: exact offsets in UTF-16, code points, UTF-8 bytes and graphemes, so the span slices back to the matched text. Tries an exact match, then a match tolerant of whitespace, curly vs straight quotes, dash types, ellipses, invisible characters and Unicode forms (NFC/NFD, ligatures), naming which normalizations were needed, then bracket-ellipsis elisions, then flags a probable paraphrase by word overlap, else not-present. Does not judge whether the source is true or the quote is representative; a paraphrase is reported with its nearest span but never counted as a match.
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/citation-span
security:
- x402: []
- apiKey: []
requestBody:
required: true
content:
application/json:
schema:
type: object
additionalProperties: false
required:
- source
- quotes
properties:
source:
type: string
maxLength: 100000
minLength: 1
description: Text the quotes are claimed to come from.
quotes:
type: array
items:
type: object
additionalProperties: false
properties:
text:
type: string
maxLength: 2000
minLength: 1
description: The quoted text.
id:
type: string
maxLength: 100
description: Echoed back.
required:
- text
maxItems: 50
minItems: 1
description: Up to 50 quotes, 40000 characters in total.
ignoreCase:
type: boolean
description: Also tolerate case differences (reported as a normalization). Default false.
tolerate:
type: array
items:
type: string
enum:
- whitespace
- quotes
- dashes
- ellipsis
- invisible
- unicode
maxItems: 6
description: 'Normalizations that still count as a match. Default: all six.'
exactOnly:
type: boolean
description: Count only byte-identical matches as pass; normalized matches become fail. Default false.
minLength:
type: integer
minimum: 1
maximum: 200
description: Quotes shorter than this many characters (after trimming quote marks) are too-short and give unknown. Default 8.
example:
source: The committee said the “pilot” would run for six months — ending in March — before a review.
quotes:
- id: q1
text: the "pilot" would run for six months - ending in March
- id: q2
text: the pilot will last half a year
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
additionalProperties: false
properties:
index:
type: integer
id:
type: string
classification:
type: string
enum:
- verbatim
- normalized
- elided
- case-differs
- paraphrase
- not-present
- too-short
occurrences:
type: integer
description: Matches found, counted to 50. More than one means the citation is ambiguous.
spans:
type: array
items:
type: object
description: 'Half-open [start,end) range in four coordinate systems: UTF-16 code units, code points, UTF-8 bytes, extended grapheme clusters (Intl.Segmenter).'
properties:
utf16:
type: object
properties:
start:
type: integer
end:
type: integer
codePoint:
type: object
properties:
start:
type: integer
end:
type: integer
utf8:
type: object
properties:
start:
type: integer
end:
type: integer
grapheme:
type: object
properties:
start:
type: integer
end:
type: integer
graphemeAligned:
type: boolean
maxItems: 5
description: Matched source ranges (one per segment for elided quotes; otherwise up to five occurrences).
matchedText:
type: string
normalizations:
type: array
items:
type: string
enum:
- whitespace
- quotes
- dashes
- ellipsis
- invisible
- unicode
- case
maxItems: 7
description: Normalizations that made the quote equal the source text.
trimmedWrapper:
type: boolean
description: Surrounding quote marks or edge ellipses were removed before matching.
overlap:
type: number
description: Share of the quote's content words found in the nearest window (paraphrase and not-present only).
nearest:
type: object
description: 'Half-open [start,end) range in four coordinate systems: UTF-16 code units, code points, UTF-8 bytes, extended grapheme clusters (Intl.Segmenter).'
properties:
utf16:
type: object
properties:
start:
type: integer
end:
type: integer
codePoint:
type: object
properties:
start:
type: integer
end:
type: integer
utf8:
type: object
properties:
start:
type: integer
end:
type: integer
grapheme:
type: object
properties:
start:
type: integer
end:
type: integer
graphemeAligned:
type: boolean
maxItems: 50
counts:
type: object
additionalProperties: false
properties:
verbatim:
type: integer
normalized:
type: integer
elided:
type: integer
case-differs:
type: integer
paraphrase:
type: integer
not-present:
type: integer
too-short:
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:
- Citation Span
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