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Queue Tumblr reblogs from a tag

You reblog the best posts under a few tags, but doing it live floods your followers' dashboards in one burst, and finding the posts takes a scroll through the tag every day.

Cotlet does it in your own Tumblr account with list_posts, get_post and reblog_post, called by your AI agent, an n8n workflow or a script.

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Hosted · nothing to install or maintain

Can Tumblr do this on its own?

Tumblr lets you reblog and queue in its composer, and its API reblogs with the parent blog UUID, post ID and reblog key (checked 17 Oct 2026). Nothing finds posts by a tag and queues the reblogs for you, and there is no official MCP server.

How you do it in Tumblr today

  1. Open the tag page, scroll through new posts and pick the ones worth sharing.
  2. Reblog a post and, in the composer, click the arrow beside Post and choose Add to queue, then Queue, so it waits for a slot.
  3. Check Account, the blog, then Queue to see what is waiting, and use Shuffle Queue if the order should be random.
  4. Tumblr publishes at most 50 queued posts per day, so a long queue spreads over several days.
  5. You repeat this each day for each tag, and nothing tells you that you reblogged a post last month.

How to queue Tumblr reblogs from a tag

Prompt

Find the 5 newest posts tagged "pixel art" from blogs I follow, skip ones I already reblogged, and add the good ones to the queue of studio-notes with my tag "found".
  1. 01

    Find the posts

    list_posts reads the posts under your tag with the tag filter, 20 at most per call, newest first. The agent keeps those from blogs you follow or from a list you gave.

  2. 02

    Skip what you shared

    It checks your own blog for a reblog of the same post, so a post you reblogged last month is not queued again.

  3. 03

    Judge each post

    get_post returns the full post, so the agent can drop posts that are only a link, are in a language you do not post in, or match a word on your skip list.

  4. 04

    Queue the reblogs

    reblog_post runs with state set to queue, so the reblog joins your queue instead of going live at once. You can add your own comment and tags. Each call waits for your OK by default, because a reblog reaches your followers.

  5. 05

    Report the batch

    The agent lists each reblog with the original blog, and names the posts it left out and why.

What you get back

Example data

Posts tagged "pixel art" checked: 20
Queued 5 as reblogs on studio-notes, tag "found":
- Harbor town sprite sheet (pixel-lab)
- 16-color palette study (tiny-pixels)
Skipped 11 (not in a followed blog)
Skipped 3 (already reblogged)
Skipped 1 (link only)

Other ways to ask

  • Every morning, queue the 3 best posts tagged "ink drawing" from blogs I follow.
  • Reblog nothing, just list the 10 newest posts under "pixel art" with their note counts.
  • Queue the reblogs with hide_trail on, so only my comment shows.
  • Reblog this one post right now with the comment "Love the palette".

What Tumblr allows, and what to know first

  • Tumblr counts reblogs in its limit of 250 new published posts per user per day.
  • A reblog in the Tumblr API needs the parent blog UUID, the parent post ID and a reblog key, and the content you send is only what you add to the trail.
  • Tumblr cannot add a video upload inside a reblog.
  • Reblogs in the queue count toward the 1,000 queued posts and the 50 posts per day Tumblr publishes from it.
  • The Tumblr API returns up to 20 posts per call, and its tag filter accepts at most 4 tags.

reblog_post asks for your OK by default. To run it daily without you, switch confirmation off for that tool in your dashboard.

Sources: Tumblr API documentation source on GitHub · Tumblr Help: Queued posts

Call reblog_post from a script

curl

curl -X POST https://cotlet.dev/api/v1/tumblr/posts/7712345600123/reblog \
  -H "Authorization: Bearer $COTLET_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"blog":"studio-notes","from_blog":"pixel-lab","comment":"The palette on this one is perfect.","tags":["found","pixel art"],"state":"queue"}'

Example response

{
  "post_id": "771204600412",
  "blog": "studio-notes",
  "state": "queue",
  "reblogged_from": "pixel-lab",
  "tags": [
    "found",
    "pixel art"
  ]
}

MCP: add https://cotlet.dev/mcp/v1 with the same key; the call is tumblr_write → reblog_post. Example data.

Schedule it in n8n, Make, Zapier or cron

Tumblr tools this automation uses

Cotlet Tumblr tools used to queue Tumblr reblogs from a tag
Tool Parameters
list_posts blog, tag, visibility, limit, cursor
get_post blog, post_id
reblog_post blog, from_blog, post_id, comment, tags, state, hide_trail
All 15 Tumblr tools with descriptions

Frequently asked questions

Is it safe to connect Tumblr to Cotlet?

Yes. You sign in to Tumblr yourself, in your own Cloud Browser in the EU, and we never save your password. Your agents only get Tumblr once you enable it, every background request is listed, and the browser profile is stored encrypted with AES-256-GCM, the cipher 1Password uses for its vaults. The AI model never sees a login, posts and messages wait for your OK, and Disable for agents cuts access in one click. Independent scanners grade cotlet.dev A+ on Qualys SSL Labs, securityheaders.com and Mozilla Observatory; live results are on https://cotlet.dev/security.

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