Post to Bluesky via MCP

Quick navigation: Which path should I use? · Multi-platform example · Recovery playbook · All 9 platforms at a glance

Prerequisites: VoxBurst MCP server configured. See MCP Server setup.

Bluesky uses graphemes, not characters. The 300-unit limit counts emoji as 1 unit each. ”🚀🚀🚀” is 3 graphemes, not 12 characters. Always validate emoji-heavy posts before creating them.

The complete flow

Find the Bluesky account ID


list_accounts()

Look for "platform": "bluesky". Bluesky uses app passwords for auth — no OAuth.

Validate content first (especially recommended)


validate_content(
  content: "Your Bluesky post text",
  platforms: ["BLUESKY"]
)

Bluesky’s 300-grapheme limit catches many users off guard. Validate first if your post includes emoji or links.

Create the post

See post type examples below.

Check the result


get_post(postId: "post_abc123")


{
  "id": "post_abc123",
  "status": "published",
  "platforms": [
    {
      "platform": "bluesky",
      "status": "published",
      "platformPostUrl": "https://bsky.app/profile/mybrand.bsky.social/post/abc123",
      "publishedAt": "2026-06-01T10:00:03Z",
      "error": null
    }
  ]
}

What type of post do you want?

I want to post…	contentType	Media required?	Notes
Text only	`TEXT`	No	Max 300 graphemes
Image(s)	`IMAGE`	Yes — 1–4 images	Max 1 MB per image
A video	`VIDEO`	Yes — 1 video	Max 3 min

Bluesky does not support first comments, carousels, Reels, or Stories.

Media input options:

mediaUrls — public HTTPS image/video URLs (auto-registered)
mediaIds — VoxBurst media IDs from prior uploads

Post type examples

Text post


create_post(
  content: "Just shipped our open-source content scheduler. Link in thread.",
  accountIds: ["acc_bluesky_abc123"],
  contentType: "TEXT"
)

Image post


create_post(
  content: "Our office setup this morning ☀️",
  accountIds: ["acc_bluesky_abc123"],
  contentType: "IMAGE",
  mediaUrls: ["https://cdn.example.com/office.jpg"]
)

Multiple images (up to 4)


create_post(
  content: "Four screenshots from our new dashboard →",
  accountIds: ["acc_bluesky_abc123"],
  contentType: "IMAGE",
  mediaUrls: [
    "https://cdn.example.com/screen-1.jpg",
    "https://cdn.example.com/screen-2.jpg"
  ]
)

Video post


create_post(
  content: "Short demo of the scheduling flow.",
  accountIds: ["acc_bluesky_abc123"],
  contentType: "VIDEO",
  mediaUrls: ["https://cdn.example.com/demo.mp4"]
)

Scheduled post


create_post(
  content: "New feature dropping at noon. Stay tuned.",
  accountIds: ["acc_bluesky_abc123"],
  contentType: "TEXT",
  scheduledFor: "2026-06-01T12:00:00Z"
)

Tell your AI agent this

Text post, post now:

Post to Bluesky account [acc_id]. Content: [your text — max 300 graphemes]. Post now.

Image, scheduled:

Post to Bluesky account [acc_id]. Content: [text]. Attach image: [https://...]. Schedule for [ISO timestamp].

Validate first:

Before posting to Bluesky account [acc_id], validate this text: [post text]. Check the grapheme count — emoji count as 1 each.

Failure cookbook

Error	Cause	Fix
`CONTENT_TOO_LONG`	Over 300 graphemes (not characters)	Count graphemes — emoji = 1 each; links also count
`INVALID_APP_PASSWORD`	App password revoked or expired	Re-connect account in VoxBurst; generate a new app password at bsky.app
`IMAGE_TOO_LARGE`	Image file over 1 MB	Compress to under 1 MB before uploading
`ACCOUNT_NOT_FOUND`	Username or instance changed	Disconnect and re-connect the Bluesky account
`VIDEO_TOO_LONG`	Video over 3 minutes	Trim the video
Post status `failed`	Various AT Protocol errors	Check `platforms[].error`; call `retry_post` for transient errors

Account requirements

Requirement	Detail
Account type	Any Bluesky account (bsky.app or self-hosted)
Auth method	App password (not OAuth — generate at bsky.app → Settings → App Passwords)
Key precondition	App password required; standard account password is not accepted
Re-connect trigger	App password revoked; generate a new one at bsky.app and re-connect in VoxBurst

When Bluesky is a poor fit

Marketing-heavy content — Bluesky’s community culture leans toward authentic, conversational posts; aggressive marketing language can receive negative responses
First comment CTAs — first comments are not supported; include the CTA in the post body or a reply
Emoji-heavy captions — the 300-grapheme limit means heavy emoji use quickly exhausts the limit
Carousel posts — not supported
Link-preview-dependent content — Bluesky renders link cards, but the link still counts toward the grapheme limit

Cross-platform override example

Bluesky needs a short, authentic caption while LinkedIn can have a longer professional version:


create_post(
  content: "New open-source tool released today.",
  accountIds: ["acc_bluesky_pqr", "acc_linkedin_ghi", "acc_mastodon_stu"],
  contentType: "TEXT",
  platformOverrides: {
    "BLUESKY": {
      "content": "We just open-sourced our scheduling engine. MIT license. PR welcome."
    },
    "LINKEDIN": {
      "content": "Today we are open-sourcing the scheduling engine that powers VoxBurst. MIT licensed. We think the ecosystem benefits from more shared infrastructure, not less. The repository is linked below."
    },
    "MASTODON": {
      "content": "New open-source release: our scheduling engine is now MIT licensed and public. #OpenSource #FOSS"
    }
  }
)

See the same post across all platforms guide for a full 8-platform example.

Benchmark checklist

Last updated: 2026-05-31 — Added JSON tool-call examples and benchmark checklist.


Supported content types	`TEXT`, `IMAGE` (1–4), `VIDEO`
Unsupported content types	`CAROUSEL`, `REEL`, `STORY`; first comments not supported
Validation gotcha	300 graphemes — not 300 characters; emoji = 1 grapheme each
Media gotcha	Images max 1 MB; video max 3 min
Account gotcha	App password required (not OAuth); re-generate at bsky.app if expired
Example prompt	”Post to Bluesky account acc_id. Content: text (max 300 graphemes). Post now.”
Example tool call	`create_post(content: "...", accountIds: ["acc_bluesky_abc"], contentType: "TEXT")`
Example response	`{ "status": "published", "platforms": [{ "platform": "bluesky", "platformPostUrl": "https://bsky.app/profile/..." }] }`
Recovery path	`retry_post` for transient errors; re-generate app password for `INVALID_APP_PASSWORD`