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postzen-devpostzen-dev/instagram-agent-skill/skills/ig-caption/SKILL.md

ig-caption

Skill34 starsChanged 29 days agoMITView on GitHub

Write the Instagram caption - the line that survives the "... more" cut, the body, the single ask, the search terms and the three hashtags - and lint it before it goes out. Use when the user says "write the caption", "caption this", "what do I put in the description", has a reel or a carousel ready and needs the text, or asks about hashtags.

11 other projects use a version of this, 7 of them edited.

Adopted by

Most recently taken up by

The file

We split this skill into the rules it gives an agent

5 rules. 3 are common, 0 are distinctive, and 2 are very specific to this project.

  • 3

    Common

    Most of the 11 edited versions we read keep these.

  • 0

    Distinctive

    This author's own choices. Worth a look.

  • 2

    Very specific

    Tied to their project's names, files or tools. Probably skip.

  • Common
  • Distinctive
  • Very specific
  1. Common:

    Ask which one you are writing.

    line 37
  2. Common:

    Ask for two or three of those terms, then pass them to the linter:

    line 78
  3. Common:

    Write the first comment separately: if there is a link. Say so in the receipt.

    line 92
  4. Very specific:

    Run /ig-human on it. Captions are short, so slop is louder here than anywhere else in the pack.

    line 105
  5. Very specific:

    Run caption.py with the user's search terms.

    line 107

“Common” is measured: kept by at least 6 in 10 of the 11 edited versions of this file we could read. “Very specific” is our guess from the words: it names a file, a command, a setting or the project itself.

Keep what fits and drop the rest. Your version, ready for your agents.
Files
SKILL.md

ig-caption

One tool lives in this folder and it runs:

python3 caption.py caption.txt
python3 caption.py caption.txt --keywords "client proposals,agency pricing"

It prints the caption the way the feed prints it: the first 125 characters in a box, everything else behind the tap. Read that box before you read anything else you wrote.

First, decide which job this caption has

This is the decision that ruins captions when it is skipped.

Job A: the video already hooked them. A Reel carries its own hook in the first two seconds, spoken and on screen. The caption is not a second hook and competing with the video is how you lose both. Its job is the ask, the context that makes the ask make sense, and the words people search.

Job B: the caption is the content. A photo, a single image, a carousel cover that opens a loop. Here line one is the hook and it works exactly like a Reel hook: concrete, short, and cut off at a cliff rather than mid-clause.

Ask which one you are writing. If the user has a Reel with a strong hook, write A and say why.

The shape

Line 1      125 characters of visible space. Job A: the ask, plainly.
            Job B: the hook.
            Never a greeting, never a hashtag, never an emoji as the first
            character.
Body        short paragraphs, one line of white space between each. Two to six
            of them. This is where the search terms live.
The ask     one. Comment a keyword, save it, or DM. One.
Hashtags    up to five, on their own line at the bottom, or none.

Limit is 2,200 characters and almost nothing needs 2,200. A caption that earns the tap and then delivers 600 characters beats one that delivers 1,800.

Hashtags, honestly

Hashtags are not a reach lever any more, and the platform has now said so with a product change. Instagram capped hashtags at five per post on 18 December 2025, down from thirty, telling creators that "using fewer (up to 5) more targeted hashtags, rather than many generic ones" performs better. Adam Mosseri had already said in February 2025 that hashtags do not work to increase reach and are a label, not a distribution lever.

So: up to five, specific, as topic labels. If the user has a block of twenty saved in their notes app, that block is now dead weight and the linter will fail it.

#viral, #fyp, #explorepage, #foryou describe nothing. Cut them.

Search terms matter more than hashtags now

Instagram search reads the caption text. So the phrase the user wants to be found for goes in the caption as a phrase a human would type, in a sentence that reads normally. "Client proposals" as words in line three, not "#clientproposals" in a block at the bottom.

Ask for two or three of those terms, then pass them to the linter:

python3 caption.py draft.txt --keywords "client proposals,agency pricing"

Rules

  • No link in the caption. Captions are not clickable. A URL in the body is dead text that says "I do not use this platform". Bio or DM.
  • One ask. Two asks is the same as none. caption.py counts them.
  • The keyword ask needs a keyword people can type. One word, no spaces, no emoji, and say it out loud in the video too. Comment CONTRACT works. Comment "the contract guide" does not.
  • Write the first comment separately if there is a link. Say so in the receipt.
  • Emoji as punctuation, not decoration. The linter flags anything over 4 per 100 characters.
  • Alt text is worth 20 seconds. For carousels and photos, write it. It is read by screen readers and by Instagram. The API does not carry it, so if the post goes out through /ig-publish, the user adds it in the app afterwards. Write it anyway and put it in the receipt.

The loop

  1. Decide Job A or Job B and say which.
  2. Draft it.
  3. Run /ig-human on it. Captions are short, so slop is louder here than anywhere else in the pack.
  4. Run caption.py with the user's search terms. Fix every FAIL. Decide on every WARN out loud rather than silently.
  5. Print the copy-ready block, then the receipt:
CAPTION READY
job:        A - the reel carries the hook
visible:    118 of 125 characters used before the cut
ask:        one, comment CONTRACT
hashtags:   3
search:     "client proposals" in line 3, "agency pricing" in line 5
linter:     READY

Nothing is posted by this skill. If the PostZen MCP tools are in this session and the media is ready, offer /ig-publish: the caption goes in as content, hashtags included, and the first comment goes in settings.firstComment. The user confirms the whole post there, with the account and the time, before anything is sent. Otherwise they paste it.

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