PostOnce
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Cursor

Add PostOnce in Cursor

This page is for people who already work in Cursor and want PostOnce as a remote MCP server. Connected means Cursor reached the hosted URL, you signed in to PostOnce in the browser, and you hit Allow. After that the agent can list accounts you already connected and write unscheduled drafts. It must not publish or schedule until you say yes. Never paste passwords, 2FA codes, refresh tokens, or API keys into the chat, and do not put a Bearer token in mcp.json.

MCP URL

Streamable HTTP. Cursor should discover OAuth and open the browser. Leave client id and secret empty.

https://postonce.app/api/mcp

How to add it

  1. Open Cursor Settings and go to MCP. Some builds nest that under Tools & Integrations. Others open the same list from Customize → MCPs.
  2. Add a custom / remote server. Name it postonce. Paste the public MCP URL above as the server URL, including /api/mcp.
  3. Save. When Cursor asks you to authenticate, sign in to PostOnce in the browser and hit Allow. Do not add an Authorization header or an API key in the config.
  4. Confirm the server shows as connected (a green status in Settings). If it stays red or yellow, refresh the server and check the URL.

Cursor labels move. If you see Add Custom MCP, New MCP Server, or Edit Config instead of Settings → MCP, it is the same paste. The server URL does not change. PostOnce is not in a global Cloud Connector catalog, so you will not find us by browsing Marketplace tiles.

You can also put this in project .cursor/mcp.json or in ~/.cursor/mcp.json for every project:

{
  "mcpServers": {
    "postonce": {
      "url": "https://postonce.app/api/mcp"
    }
  }
}

A server that never authenticates is often a closed browser window, or JSON that added headers with a pasted secret. Delete the header, save, and let Cursor open OAuth again. Team allowlists can also block a URL that is not on the admin list; in that case the workspace admin has to approve https://postonce.app/api/mcp.

After you connect

In Agent chat, ask Cursor to list your PostOnce accounts first. Then ask for an unscheduled draft, read the copy and the targets, and say yes only when you want it scheduled or published. Cursor may ask you to approve each tool call; that is expected. If Instagram or TikTok is missing, the agent should send you to postonce.app/accounts and stop. It must not ask for passwords, 2FA codes, refresh tokens, or API keys in the chat. Hosted MCP can pull a public image or video URL onto the PostOnce CDN; files dropped into the Cursor chat still cannot.

Prompts that work in Cursor Agent

Use these after the PostOnce server is green. Say no if the agent offers to publish.

  • “Using the PostOnce MCP server only, list my connected social accounts.”
  • “What PostOnce workspace and plan am I authenticated as?”
  • “Create an unscheduled PostOnce draft that says “Thursday late opening, 5–8pm” for an Instagram account already in the workspace. Do not schedule or publish.”
  • “Show the draft you just wrote in PostOnce. Do not call publish or schedule.”

Price

PostOnce Solo is €15/month, or €12/month billed yearly (€144/yr). Pro is €30/month, or €25/month billed yearly (€300/yr). Those are VAT-inclusive list prices: no per-channel fee, no free plan, and signup is Lemon checkout.

Buffer Essentials is $6 per channel monthly, or $5 per channel if billed yearly, so five connected accounts is $30/month on monthly Buffer ($25/month effective yearly). Post Bridge's public Creator plan is $29/month for 15 connected accounts. Solo at €15/month sits against Post Bridge Creator at $29/month, and against Buffer at $30/month for five channels. Those figures are EUR and USD as published.

PostOnce pricing

Other clients

Same server for ChatGPT, Grok, and Claude. Technical fields live on the MCP connect page.

Stuck? Email [email protected]. Privacy · Terms

Lucro Limited, Ireland. Company no. 811725.

Questions: [email protected]

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