Cross-posting is publishing the same piece of content, sometimes adapted, to more than one social network or account.
Cross-posting done well
Pure copy-paste saves time but ignores that each network has different limits and norms. Adapted cross-posting keeps the message and changes the form.
| Network | Main constraint |
|---|---|
| X | 280 weighted characters per post |
| Bluesky | 300 graphemes per post |
| Mastodon | 500 characters by default, set per server |
| Longer single posts; no native threads |
Beyond length: hashtags work differently, link previews behave differently, and a LinkedIn audience expects more context than an X audience.
An example
One release note becomes a 3-post X thread, a 2-post Bluesky thread, a single Mastodon post under 500 characters, and a 900-character LinkedIn post that opens with the problem the release solves.
Why it matters for AI-agent publishing
Agents are good at adapting one message to several formats, which makes cross-posting cheap. The risk is volume: the same mistake lands on four networks at once. Review each version, not just the first.
SocialHandoff publishes to X, LinkedIn, Bluesky, Mastodon, Threads, Instagram, Facebook, and TikTok, and applies per-network length guardrails. preview_posts shows how each version will look before approval. Check your text against every limit at once with the cross-post length checker, and see content repurposing for the broader practice.