Three caption variants plus hashtags, with per-platform length limits

An agent prompt that writes three captions (short, story, question) and a hashtag set per platform, counting characters and hashtags against limits you paste in from today's upload form.

Write captions for the video described below, for these platforms: {TikTok, Reels, Shorts, LinkedIn}.

Limits to respect (parameters; I checked them against the upload forms today): {TikTok: caption max 4000 characters, 3-5 hashtags; Reels: caption max 2200 characters, 30 hashtags max, use 3-5; Shorts: title max 100 characters, description max 5000, 2-3 hashtags; LinkedIn: post max 3000 characters, 3-5 hashtags, first 2 lines visible before 'see more'}.

For each platform, three variants:
A. SHORT: one line, max 80 characters, the hook of the video in text form.
B. STORY: 2-4 short lines, what happened and the one takeaway; for LinkedIn, the first line must stand alone before the fold.
C. QUESTION: one line that asks the viewer something they can answer in a comment, max 100 characters.

Then hashtags per platform: the stated count, mixed as 1 broad, 2 topic, 1-2 niche; no hashtag that is a brand I do not own; lowercase; no spaces.

Output per platform: the three variants with their character counts, the hashtag line with its count, and a one-line note if any limit was close.

Rules: no emoji unless the platform list says so; no 'link in bio' unless I give a link; numbers and names exactly as in the video; nothing claimed that the video does not show.

Video:
{one-paragraph description, the hook line, the CTA}

In Claude Code, paste the prompt as a message.

Steps

  1. Open each platform's upload form and check the current caption and hashtag limits; paste them into the limits line. They change, and the agent's memory of them is stale.
  2. Pick one variant per platform; a different variant per platform costs nothing and tells you which kind of caption your audience answers.
  3. Keep the chosen caption and hashtags in a text file beside the video with the posting date.

Tips

  • The question variant is the one that gets replies; the short variant is the one that gets saves. Which you want depends on the video.
  • On LinkedIn the first line is the whole caption for most readers. Put the number there.
works withClaude Code: Runs as a skill or a prompt in the terminal; can read your files and write the result. · Claude: Paste into claude.ai or the Claude app. · ChatGPT: Paste into ChatGPT; works with any GPT model. · Any LLM: Model-agnostic: Gemini, Mistral, a local model.
costFree. No API, no key.
statusUnverified: written from the technique, not yet run end to end by us.
licenseCC BY 4.0 for the text here; skills are MIT.
updated2026-11-01
for agentscaption-variants-hashtags-per-platform-prompt.md
#captions#hashtags#platforms#agent#social#limits

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