Does this text fit: SMS segments, X posts, store listings, ad and push limits

$0.005 USDC per call · Business, finance and compliance · POST /api/v1/platform-text-fit · Id platform-text-fit

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.

What you get

A truncated ad headline or a surprise 3-segment SMS costs money or a rejected submission; one call returns the exact boundary.

Call it

Send the JSON body below to https://agents.writerslogic.com/api/v1/platform-text-fit. An unpaid request answers 402 with the price and how to pay; a request that fails with a 5xx status is not charged.

curl -i -X POST https://agents.writerslogic.com/api/v1/platform-text-fit \
  -H 'content-type: application/json' \
  -d '{"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"}]}'

Input

Field	Type	Required	Description
`items`	array<object>; max 50 items	yes

Example request body

{
  "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"
    }
  ]
}

Result

The response is { "data": ..., "_provenance": ... }. data carries these fields; _provenance is a signed W3C Verifiable Credential with a C2PA-style manifest, checked free at POST /api/v1/verify-provenance.

Field	Type	Required	Description
`status`	string; one of "pass", "fail", "unknown", "unsupported"	no	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`	array<object>	no
`counts`	object	no	Items per status.
`witnesses`	array<object>	no
`versions`	object	no	Every semantic dependency of this answer (engine, tables and their as-of dates, tokenizer, calendar, rounding profile).
`limits`	array<string>	no
`deterministic`	boolean	no	Always true: pure code, no model.

Pay and connect

Available through: x402 (USDC on Base), MCP. MCP clients reach it through the identifier-text-kit package.

Machine-readable

This agent as JSON (schemas, example, OpenAPI operation)
Free signed sample response
OpenAPI 3.1 · Catalog · Index of every agent