Prompt
(AI Agent node system prompt) Write one Facebook Page post for a new event from the calendar item: title, date and time, place, one sentence on why to come, and the registration link. Under 90 words. Output only the post.How to do it
- Connect Facebook and mint a key In https://app.socialhandoff.com, open Connections, sign in with Facebook and pick the Pages to connect; each Page becomes its own channel. Then create an agent key named n8n scoped to Facebook with draft permission.
- Set up the trigger Start with a trigger, for example a Google Calendar event created, and generate the text with an AI Agent node or an expression.
- Import media by URL Add an HTTP Request node: POST https://app.socialhandoff.com/v1/media/import with JSON {"url": public https link, "alt": description} for photos (up to 10, each with alt text) or one video. No multipart needed. Keep the id it returns for the next step.
- Create the post Add an HTTP Request node: POST https://app.socialhandoff.com/v1/posts with a bearer header and JSON body {"body": text, "networks": ["facebook"], "mode": "submit"}, adding "mediaIds" only when photos were uploaded. The post lands in the approval inbox.
- Approve for the right Page The card shows which Page the post goes to. Approve on desktop or in the phone swipe stack, and it publishes to that Page at the scheduled time.
Example draft
Free workshop: Intro to home composting. Saturday, November 8, 10:00 to 11:30, at the community garden shed. Learn what to compost, what to skip, and how to avoid the smell, then take home a starter bag. Register here: https://example.com/events/composting
Gotchas
- Calendar triggers fire again when an event is edited. Send an idempotencyKey built from the event id so an edit returns the existing draft instead of creating a second one.
- Facebook Page tokens do not expire, but removing the app's access in Facebook disconnects the Page. Reconnect it in Connections.
- The import URL must be public https. A cloud storage link that needs sign-in fails the import; use a shared link or a presigned URL in the expression.
- Only Facebook Pages can be connected, not personal profiles. Every Page you grant at sign-in becomes its own channel, so check which Page the card names before approving.
- Where you can post: Facebook Pages only. The API does not allow posting to personal profiles or to Groups through SocialHandoff.
- Page access: You need a role on the Page that allows creating content.
- Photos: One photo with alt text, or up to 10 photos in one post.
- Video: One video per post.
Frequently asked questions
Can I post to a personal Facebook profile?
No. Meta only allows API publishing to Pages. Personal profiles cannot be connected.
Can I use the MCP Client Tool instead of HTTP Request?
Yes. The MCP Client Tool exposes attach_media and draft_post to the AI Agent node. The HTTP Request node is simpler when the workflow, not the model, decides which file to attach.
Do Facebook Page posts need an image?
No. A Page post can be text and a link, one or more photos (up to 10), or one video.