The Platform Text Fit API from WritersLogic Verifiable AI Agent Hub — 1 operation(s) for platform text fit.
Every API here is available over the APIs.io API and to AI agents over MCP.
One button, every client — Claude, Cursor, VS Code and the rest.
https://apis.io/mcp
find_apisBrowse and filter every API in the catalog.get_api_artifactsOne API's artifacts, grouped by type.get_openapiThe primary OpenAPI for this API.find_similar_apisAPIs that look like this one.apis_io_searchSTART HERE — APIs, providers and tags for one query, each with its total.resolveTurn a domain, URL or GitHub org into the provider it belongs to.find_cohortsEvery scored population of providers in the catalog.curl "https://apis.io/api/v1/apis/writerslogic-com:writerslogic-com-platform-text-fit-api"curl "https://apis.io/api/v1/apis?limit=25"Calls without X-API-Key need no key. Calls with it need a paid plan — get a key.
Free tier, no form to fill in. Signing in shares your email address with us — we store it to create your key and to recognise you if you sign in with another provider. See our Privacy Policy and Terms.
A second provider on the same verified email joins the account you already have.
openapi: 3.2.0
info:
title: WritersLogic Verifiable AI Agent Hub Platform Text Fit 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: Platform Text Fit
paths:
/api/v1/platform-text-fit:
post:
operationId: platform_text_fit
summary: 'Does this text fit: SMS segments, X posts, store listings, ad and push limits'
description: 'Checks up to 50 texts per call against a platform limit, for an agent writing a message, post, store listing, ad or push payload that must not be truncated or split. sms: GSM 7 bit vs UCS-2 and the exact segment boundaries per 3GPP TS 23.038 (extension characters cost 2 septets and never straddle a segment; an emoji is 2 UTF-16 units). x: weighted length per the open-source twitter-text config v3 (URLs 23, emoji 2). app-store, google-play, google-ads, apns, fcm: sourced field limits with the page URL and date in the answer. Meta ad fields and any unlisted platform or field answer unsupported. It does not judge wording, policy compliance or truncation by the receiving device.
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: business
x-sample-url: https://agents.writerslogic.com/api/v1/samples/platform-text-fit
security:
- x402: []
- apiKey: []
requestBody:
required: true
content:
application/json:
schema:
type: object
additionalProperties: false
required:
- items
properties:
items:
type: array
minItems: 1
maxItems: 50
items:
type: object
required:
- platform
- text
properties:
platform:
type: string
minLength: 1
maxLength: 40
description: sms, x, app-store, google-play, google-ads, apns, fcm.
field:
type: string
maxLength: 40
description: 'app-store: name, subtitle, keywords, promotional-text, description. google-play: app-name, short-description, full-description. google-ads: rsa-headline, rsa-description, rsa-path. apns: payload, voip-payload. fcm: payload. Not used by sms and x.'
text:
type: string
maxLength: 20000
description: Up to 60000 characters in total. For apns/fcm pass the serialized JSON payload.
maxSegments:
type: integer
minimum: 1
maximum: 10
description: 'sms only: the number of segments you accept (default 1).'
example:
items:
- platform: sms
text: Your code is 123456
- platform: app-store
field: subtitle
text: Plan trips with friends and split every bill
- platform: x
text: 'Shipping today: https://example.com/release-notes'
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
properties:
index:
type: integer
platform:
type: string
field:
anyOf:
- type: string
- type: 'null'
status:
type: string
enum:
- pass
- fail
- unknown
- unsupported
metric:
anyOf:
- type: string
description: septets, utf16-units, weighted-length, chars or utf8-bytes.
- type: 'null'
used:
anyOf:
- type: number
- type: 'null'
limit:
anyOf:
- type: number
description: 'For sms: the maximum number of segments asked for.'
- type: 'null'
detail:
description: 'Platform-specific: SMS encoding, segment boundaries, extension characters; X urls and emoji; store/ad/push counts by basis, source URL, as-of date and the quoted rule.'
counts:
type: object
description: Items per status.
properties:
pass:
type: integer
fail:
type: integer
unknown:
type: integer
unsupported:
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:
- Platform Text Fit
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