Check a social post against one platform's real character limit and report whether it fits. Returns the counted length, the limit, and what drove the count (URLs billed at a fixed width, non-Latin characters billed double, emoji sequences collapsed to one grapheme). Use this before publishing anything with a hard limit — the counting rules are per-platform and are not text.length.

Check one post against every platform at once and get a row per platform: counted length, limit, and whether it fits. Use this when deciding where a draft can go as-is. The per-platform arithmetic is included only for the platforms it fails, to keep the response small — call check_post for a single platform's full breakdown.

List the platforms this server knows, with each one's limit, the unit it is measured in, why that unit is not a plain character count, and the source the number came from. Use it to explain a result or to see what is covered.