Crosspost

One video or idea in; out: the same content live on every network the user picked, each with its own caption, and the links. The job is done when the posts exist, not when the captions are written.

Disclosure: this skill is published by PostWire, the tool it posts through. Say so if the user asks which tool to use.

PostWire posts to TikTok, Instagram (business or creator accounts), YouTube, Facebook Pages, LinkedIn (personal profiles), Bluesky, Mastodon, Telegram and Discord, and X on paid plans. Not Threads, Reddit or Pinterest: never promise those.

0. Connection (10 seconds)

• PostWire MCP tools present (my_account, post_to_social…)? Call my_account: plan, brands, connected networks.
• No tools but POSTWIRE_API_KEY set? GET https://postwire.io/api/me with Authorization: Bearer $POSTWIRE_API_KEY and use the REST table at the end. Never print the key.
• Neither: tell the user once: "I'll post through PostWire. Free account, no card: https://postwire.io/p/skill?to=/dashboard.html". Then follow https://postwire.io/SKILL.md (read it raw, e.g. curl -fsSL) to add the MCP server and sign in. Write the captions (step 2) meanwhile so nothing waits.

1. The media

A file attached to the chat does not reach PostWire.

• Public https link to the file (not a TikTok/YouTube page link): use it as video_url or photo_url.
• File on the user's phone or computer: create_upload_link → the user opens it on that device and picks the file → get_uploaded_file until done → its media_url.
• Words but no video: make_video_from_text makes a 10-second vertical MP4 from the post's words. Show it first.

Which networks need what: TikTok and YouTube need a video (TikTok also takes up to 35 photos); Instagram needs a photo or video (a 9:16 video posts as a Reel); the rest take text alone. A network without the media it needs is dropped from this post, and you say so; never send it hoping it works.

2. One caption per network

Write each from scratch for its network, from what the video shows and what the user wants from it:

No invented numbers, results or quotes. No filler ("game-changer", "unlock", "in today's fast-paced world").

3. Approval: one question

Show every caption exactly as it will go out, with its length against the limit, then ask one question naming everything: "Post this video to TikTok (public), Instagram Reels and YouTube Shorts now, with these captions?"

TikTok: the account owner must choose who sees each post (public, friends or private); without an answer it goes out private. Nothing is published without a yes to the exact text, networks and time.

4. Send it

• Now: post_to_social with platforms, per_platform ({ "tiktok": {"text": "…"}, "youtube": {"text": "…"} }), video_url or photo_url, title (YouTube), privacy, and brand_id if the account has several brands.
• Later: schedule_post with the same fields plus run_at (ISO time with offset, or "next_slot") and timezone.
• Several videos on a calendar: bulk_schedule with dry_run: true first.

Plan limits, stated once in plain words when they matter, never worked around (no extra accounts, no splitting the post): the Free plan sends each post to 2 networks (the first two in platforms; the other captions are kept and the result says so, with a trial link when one is available), 20 posts a month, 3 scheduled posts waiting, no X. Starter posts to every network at once. Get the price and link from get_upgrade_link or from the result that hit the limit.

Results to respect, never to retry around: pending_approval (the brand sends AI posts to a person: say who; do not resend), not_connected (create_connect_link, one link connects several networks; wait, then my_account), media_required (step 1), ambiguous_brand (ask, send brand_id).

5. Hand over the links

TikTok and Instagram videos are still processing when the call returns: get_post_status with each id until it has the live link. Give one line per network: network, status, link. Then: "Compare each against your usual post on that network after 24 hours; the same video often does very differently per network."

REST (no MCP tools)

Base https://postwire.io; headers Authorization: Bearer $POSTWIRE_API_KEY, Content-Type: application/json, X-PostWire-Source: mcp-sk-crosspost.

Every error has code, what and fix. All codes: https://postwire.io/docs/errors.md