How to schedule YouTube Shorts with your AI agent
By PostPen Team ·
A YouTube Short is a short vertical video. PostPen schedules them like any other post: choose Short for the post, set the time, and PostPen uploads it to your channel. Before it's scheduled, PostPen checks the video against YouTube's rules for Shorts, so a clip that would post as a normal video doesn't go out by mistake.
Start free and connect YouTube. Your agent writes, PostPen schedules and publishes.
What YouTube says a Short is
YouTube's Upload YouTube Shorts page (YouTube Help, checked November 3, 2026) lists two rules for the video file: "Up to 3 minutes" and "With a square or vertical aspect ratio."
Video or Short, per post
Each YouTube post in PostPen is either a normal video or a Short, and you choose per post:
- In the Composer, pick Video or Short in the YouTube settings. The preview shows a Short in a vertical frame, with the title and description as they'll be sent.
- From your agent,
save_draftorschedule_posttakesyoutube_format:"video"(the default) or"short".
What PostPen checks before scheduling
| Check | What happens |
|---|---|
| Longer than 3 minutes | Refused as a Short. Post it as a Video instead |
| Landscape (wider than tall) | Refused as a Short, because YouTube would post it as a normal video |
| Vertical or square, but not 9:16 | Allowed, with a warning that YouTube may show bars |
| Size or length can't be read | Allowed, with a reminder of the rules |
A refused Short never goes out as something else. You see the reason under the post in the Composer, and your agent gets it in network_problems.
#Shorts, added for you
PostPen makes sure a Short carries #Shorts. If neither the title nor the description has it, PostPen adds it to the end of the title when it fits in YouTube's 100 characters, and otherwise to the description. If both are full, the title is shortened to make room.
The rest of the settings
A Short takes the same settings as any YouTube upload in PostPen:
- Title up to 100 characters. Without one, PostPen uses the first line of your text.
- Description from your text, up to 5,000 bytes. YouTube refuses
<and>in either. - Privacy: public by default, or unlisted or private.
- Tags, a category, and whether it's made for kids.
A YouTube post takes exactly one video and nothing else. See the YouTube scheduler for everything PostPen does on YouTube.
Ask your agent to schedule a Short
Schedule this vertical clip as a YouTube Short for Saturday at 6 PM, titled "Three deploy fixes in 60 seconds", and post it to Instagram too.
Your agent finds your channel with list_destinations, uploads the video, saves the draft with youtube_format: "short" and the title, and schedules it. The same video can go to Instagram, Facebook, Threads, X and LinkedIn in the same post, each with its own text.
After it's up
The post shows on your PostPen calendar with its YouTube link once it's published. PostPen reads its views, likes and comment counts, and your agent can read the same numbers with get_post_stats.
FAQ
Yes. In PostPen, choose Short for the post, in the Composer or with youtube_format "short" from your agent, and set the time. PostPen uploads it to your channel then.
Up to 3 minutes. YouTube Help lists Shorts as up to 3 minutes with a square or vertical aspect ratio.
PostPen refuses it as a Short and asks you to post it as a Video instead, because YouTube would post a landscape clip as a normal video.
Yes. If neither the title nor the description has #Shorts, PostPen adds it to the title when it fits in 100 characters, and otherwise to the description.
Yes. A post can go to YouTube as a Short and to Instagram, Facebook, Threads, X and LinkedIn as a video, with its own text for each.
Schedule your first Short
Connect YouTube, add PostPen to your agent, and hand it a vertical clip.
Start free and connect your agent. Your agent writes, PostPen schedules and publishes.