The Text Offsets API from WritersLogic Verifiable AI Agent Hub — 1 operation(s) for text offsets.
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openapi: 3.2.0
info:
title: WritersLogic Verifiable AI Agent Hub Text Offsets 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: Text Offsets
paths:
/api/v1/text-offsets:
post:
operationId: text_offsets
summary: Convert text offsets between UTF-16, code points, UTF-8 bytes and graphemes…
description: 'Reports the length of a string in UTF-16 code units, Unicode code points, UTF-8 bytes and extended grapheme clusters (Intl.Segmenter), converts up to 200 ranges given in any one of those units into all four, and flags ranges that fall inside a surrogate pair, a multi-byte UTF-8 character or a grapheme cluster. It also runs the unicode-check rules (bidi controls, zero-width and invisible characters, tag characters, confusables) and returns each finding''s offsets in all four systems, plus line-ending, BOM, normalization-form (NFC/NFD) and unpaired-surrogate facts. Grapheme boundaries follow the ICU version of this runtime. Does not decode bytes or fix text.
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/text-offsets
security:
- x402: []
- apiKey: []
requestBody:
required: true
content:
application/json:
schema:
type: object
additionalProperties: false
required:
- text
properties:
text:
type: string
maxLength: 50000
minLength: 0
description: The string.
ranges:
type: array
items:
type: object
additionalProperties: false
properties:
unit:
type: string
enum:
- utf16
- codePoint
- utf8
- grapheme
start:
type: integer
minimum: 0
maximum: 10000000
end:
type: integer
minimum: 0
maximum: 10000000
required:
- unit
- start
- end
maxItems: 200
description: Half-open ranges to convert; each is read in its own unit.
kind:
type: string
enum:
- text
- identifier
- url
description: How the unicode rules treat the string. Default text.
scan:
type: boolean
description: Run the hidden-Unicode rules. Default true.
example:
text: naïve 👨👩👧 evil
ranges:
- unit: grapheme
start: 6
end: 7
- unit: utf8
start: 6
end: 8
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.'
lengths:
type: object
additionalProperties: false
properties:
utf16:
type: integer
codePoints:
type: integer
utf8Bytes:
type: integer
graphemes:
type: integer
properties:
type: object
additionalProperties: false
properties:
illFormed:
type: boolean
description: Contains an unpaired surrogate; UTF-8 encoders write U+FFFD (3 bytes) for each.
bom:
type: boolean
lf:
type: integer
crlf:
type: integer
cr:
type: integer
description: Lone carriage returns.
nfc:
type: boolean
nfd:
type: boolean
ascii:
type: boolean
ranges:
type: array
items:
type: object
additionalProperties: false
properties:
index:
type: integer
unit:
type: string
enum:
- utf16
- codePoint
- utf8
- grapheme
start:
type: integer
end:
type: integer
valid:
type: boolean
error:
type: string
span:
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
text:
type: string
maxItems: 200
unicode:
type: object
additionalProperties: false
properties:
verdict:
type: string
enum:
- BLOCK
- REVIEW
- NO_FINDING
findings:
type: array
items:
type: object
additionalProperties: false
properties:
ruleId:
type: string
ruleName:
type: string
severity:
type: string
codePoints:
type: string
charInfo:
type: string
span:
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: 10
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:
- Text Offsets
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