How to set up the Sandcastles MCP in Gemini

Connecting Sandcastles to Gemini

You can add Sandcastles to the Gemini app as a custom app, then mention it in your prompts to research your Watchlist, videos and channels. You add it once in the Gemini web app on a computer, and then it also works in the Gemini mobile app.

Before you start

• You need a Sandcastles Pro, Visionary or Titan plan. The MCP isn't included in the Starter plan.
• To add custom apps in Gemini, you need to be 18 or older, in the US, and signed in with a personal Google Account (not a work or school account).
• Keep Activity must be turned on in Gemini.
• Custom apps in Gemini only work in English.

Get your Sandcastles MCP URL

1. Open Sandcastles and go to Settings > Connectors.
2. In the MCP card, hover over the URL and click Copy. The URL is https://mcp.sandcastles.ai/.

If you're on the Starter plan, the MCP card shows a See plans button instead of the URL. Upgrade to Pro or higher to continue.

Add Sandcastles to Gemini

1. On a computer, go to gemini.google.com.

2. Click Settings > Connected Apps. If you don't see Connected Apps, click Personal Intelligence first, then Connected Apps.

3. Under Custom apps, click Add a custom app.

4. Enter the Sandcastles MCP URL:

   https://mcp.sandcastles.ai/
   

   Copy

5. Click Next.

6. Follow the on-screen steps to sign in with your Sandcastles account and approve access.

Use Sandcastles in Gemini

1. In a Gemini prompt, type @ and choose Sandcastles.

2. After Sandcastles is selected, describe what you want in plain language. For example:

   Show me the top videos in my Watchlist from the last 7 days and break down their hooks and formats.
   

   Copy

Gemini asks you to confirm before Sandcastles makes any change for you, such as adding channels to your Watchlist, analyzing a new video or creating a project.

Disconnect Sandcastles

1. In Gemini, go to Connected Apps.
2. Click More details next to Sandcastles.
3. Click Disconnect.

Important notes

• If your account isn't on a Pro, Visionary or Titan plan, Sandcastles returns this message instead of results: "Your Sandcastles plan doesn't include MCP access."
• Analyzing a video that isn't in your workspace yet uses 1 credit. If the video is already in your workspace, it doesn't use another credit. If you run out, you'll see "You don't have enough credits to perform this action."
• The MCP works in the workspace you last had open in Sandcastles. Ask Gemini to list your workspaces or switch to another one. Switching in Gemini also changes the workspace you see the next time you open Sandcastles.
• Gemini doesn't have the "/" commands from the Sandcastles Claude plugin, but it has access to the same Sandcastles tools.

Related articles

• How to set up the Sandcastles MCP in any AI assistant
• How to set up the Sandcastles MCP in Google Antigravity
• How to set up the Sandcastles MCP in Claude
• Does using the Sandcastles MCP cost credits?

If you have any questions, please reach out to support@sandcastles.ai.