MCP Setup: Connecting Merlin Project to Antigravity

Antigravity is Google's agentic editor, and for MCP servers it uses the same kind of configuration as Claude Desktop: one block in a JSON file telling the editor which program to start. One trait sets Antigravity apart from the other clients. It reads that file only at launch, so anyone who sees no connection after saving tends to look for the error in a file that has long been correct. What follows is the click path to the configuration, the block to copy, and the restart without which nothing happens.

The video for this article

The video (in German) is embedded in the German version of this article.

What you need

• Merlin Project, current version, MCP server installed, project shared
• Antigravity for Mac

The Merlin side is the same for every client:

1. Install the server. In Merlin Project, open the Merlin Project menu and choose Install MCP Server. Merlin places a small program on your Mac, the bridge between AI client and plan. The installer shows the path; it is /usr/local/bin/merlinproject-mcp.
2. Share the project. Open the project and click AI Tools in the toolbar. Check Allow AI tools to interact with document; the symbol is shown filled. Sharing applies to this one project only, all others stay invisible to the server. As soon as a client is connected, the symbol turns blue.

local · read-only · not reachable from outside. The server only reads the projects you share, changes nothing in your data, and nobody can reach it from outside. What a cloud client sees of the data it reads is explained in the privacy article.

Step 1: add the config

The route to the configuration file leads through the agent session:

1. In Antigravity, open an agent session.
2. In the side panel, click the … menu and choose MCP Servers.
3. At the top of the MCP store, click Manage MCP Servers and then View raw config. The file mcp_config.json opens.
4. Add the following block and save.

Config block for merlin-project mcp_config.json

{
  "mcpServers": {
    "merlin-project": {
      "command": "/usr/local/bin/merlinproject-mcp"
    }
  }
}

Important: only add to the file. If it already has content, delete none of it, or Antigravity loses other servers you have already set up.

Step 2: restart Antigravity

Save, and look at the MCP list: Merlin is missing. The config is in place, and Antigravity shows no connection. The reason: Antigravity reads this file only at launch. As long as the app is running, it knows nothing about your entry, no matter how often you save.

That is why the second step is a full restart. Closing the window is not enough; quit Antigravity via Cmd+Q and open it again. After that, merlin-project is in the list of connected servers. Skip this step, and you see no connection and hunt for the error in a file that has long been correct.

The first question: a phase as a checklist

After the restart you can ask. In the video, a task group is output as a checklist so it can go straight to the team:

Prompt: How do I turn a phase into a checklist?

Export all tasks of the group {PHASE} from the active project as a Markdown checklist: one line per task with a checkbox, assigned resource, and date. Mark already completed tasks as done. The list should paste directly into notes or a wiki.

Open this prompt in the library ›

Replace the placeholder with the name of the phase, for example "4 Go-to-Market". Antigravity reads tasks, assignments, and progress from the plan and delivers checklist and table, both ready to reuse.

If nothing shows despite the restart

• Check the JSON. One missing comma is enough for Antigravity to discard the file. Copy the block from this page.
• Check the path. The installer in Merlin Project shows the path; it must match the value in the file exactly.
• Check sharing. Is the project shared in Merlin via "AI Tools"?
• Really quit? The red close button does not quit the app. Check the Dock whether Antigravity is still running, then Cmd+Q.

Checklist

For practice, use the sample project Produktlaunch Phoenix. More export formats are in the prompt library. All setup guides:

• Claude Desktop: One block in one file, restart
• LM Studio: Download a model, one block in one file
• Claude Code: One command
• Codex: One command
• Antigravity (this article): One block in one file, full restart
• ChatGPT: Copy bridge or Intelligent Assistant
• Which AI client suits you?

If you have any questions about this blog article or would like to discuss it, we look forward to your contribution in our forum.