X (Twitter) tweet formatter

Take tweet text the user already has and make it read well on X without changing what it says. Then check it fits.

Line breaks and lists

• Line breaks survive publishing. Use them to separate the hook from the body and to give each point its own line.
• One blank line between blocks. Don't double-space every line of a short tweet.
• Lists: one item per line with a simple marker (-, →, or 1.). Keep markers consistent.
• Keep the hook on line 1 by itself when the tweet has more than two lines.

Unicode bold and italic

X has no native bold or italic in regular posts. "Bold" text is made of Unicode math letters (𝗯𝗼𝗹𝗱, 𝘪𝘵𝘢𝘭𝘪𝘤). Tell the user the costs before using them:

• Screen readers often read these characters letter by letter or as symbol names, so people using them can't follow the text.
• Search, including X search, usually doesn't match them to normal letters, so those words don't help the tweet get found.
• Each styled letter may count as 2 characters against the limit.

If the user still wants it, style 1–3 words at most, never a whole sentence, never hashtags or names. Offer caps or a line break for emphasis instead.

Counting and the limit

The limit is 280 characters, or 4,000 if the account had X Premium when it was connected to PostOnce. Text over the limit is cut off at publish, not rejected, so the ending is lost silently. When counting:

• Count emoji, CJK characters and Unicode-styled letters as 2.
• Count every character of a link to be safe, even though X shortens links.

Splitting over-limit text

When the text is over the limit, offer the choices in this order:

1. Tighten. Cut filler words, repeated ideas and throat-clearing openers. Show what was removed.
2. Split into standalone tweets. Each one must make sense alone; schedule them separately.
3. Thread. Use x-thread-generator. The MCP can't publish reply chains, so that skill explains the ways to ship it.
4. Long post. Only for X Premium accounts, up to 4,000.

Never split mid-sentence or mid-list, and never add "(1/2)" to text that will be posted as separate standalone tweets.

Output

Return the formatted tweet exactly as it will appear, its character count, and a one-line note on what changed. If it was split, number the parts with their counts. Offer to publish or schedule with the postonce skill; confirm the account and time before create_post.