Gemini CLI MCP and Extensions After the Antigravity Move

If you set up MCP servers or extensions in Gemini CLI, the ground moved under you: on June 18, 2026, Google stopped serving Gemini CLI for free, Google AI Pro and Google AI Ultra users and moved them to Antigravity CLI. Gemini CLI still runs for some accounts, and its MCP setup still matters for them. This guide covers both, from Google's announcement, the Gemini CLI docs and the Antigravity docs, checked October 22, 2026.

The short version: on a personal plan, use Antigravity CLI (agy): put MCP servers in ~/.gemini/config/mcp_config.json, use serverUrl for remote ones, and open /mcp to manage them; agy plugin import gemini converts old extensions. On a Gemini Code Assist Standard or Enterprise license, or with a paid API key, Gemini CLI still works: gemini mcp add adds a server and gemini extensions install adds an extension.

Can I still use Gemini CLI?

Google's announcement says Gemini CLI and the Gemini Code Assist IDE extensions stopped serving requests on June 18, 2026 for Google AI Pro, Google AI Ultra and free individual users. It keeps working for Gemini Code Assist Standard and Enterprise licenses, for Gemini Code Assist for GitHub through Google Cloud, and with paid Gemini and Gemini Enterprise Agent Platform API keys. Everyone else moves to Antigravity CLI, which keeps skills, hooks, subagents and extensions, the last now called Antigravity plugins.

How do I add an MCP server to Gemini CLI?

gemini mcp add --transport http my-server https://api.example.com/mcp/

The pattern is gemini mcp add [options] <name> <command or url>. The default transport is stdio; use --transport http for a remote server, -e KEY=value for environment variables, -H for headers and --scope user to make it available everywhere (the default scope is the project). Servers are stored under mcpServers in ~/.gemini/settings.json or the project's .gemini/settings.json, where a remote server's address is httpUrl. gemini mcp list shows them, gemini mcp remove <name> deletes one, and /mcp inside Gemini CLI shows each server's status and tools; /mcp auth <name> signs in to a server that uses OAuth.

Two details that trip people up: name servers with dashes, not underscores, because tool names become mcp_{server}_{tool} and the policy parser splits on underscores; and only set trust on a server you would let run without asking, because it skips every confirmation.

What are Gemini CLI extensions?

An extension bundles MCP servers, commands, context files and settings into one install. Each has a gemini-extension.json manifest in its root and lives in ~/.gemini/extensions.

gemini extensions install https://github.com/gemini-cli-extensions/workspace
gemini extensions list
gemini extensions update --all

Gemini CLI copies an extension when it installs it, so run gemini extensions update to pick up changes; --auto-update at install time does it for you. Browse published extensions at the extensions gallery.

How do I add an MCP server to Antigravity CLI?

Antigravity reads MCP servers from ~/.gemini/config/mcp_config.json, or .agents/mcp_config.json in a workspace. A remote server uses serverUrl; Antigravity does not accept the old url or httpUrl keys:

{
  "mcpServers": {
    "my-remote-server": {
      "serverUrl": "https://api.example.com/mcp/",
      "headers": { "Authorization": "Bearer YOUR_API_TOKEN" }
    },
    "sqlite-explorer": {
      "command": "node",
      "args": ["/usr/local/bin/sqlite-mcp-server.js"],
      "env": { "SQLITE_DB_PATH": "/var/data/app.db" }
    }
  }
}

Restart agy after editing the file, then type /mcp to open the MCP manager and check each server. Prefer OAuth over a token in headers where the server offers it, so no secret sits in the file.

How do I move my Gemini CLI setup to Antigravity CLI?

1. Run agy. On first launch it finds your Gemini CLI profile and lists the extensions and settings it can convert; tick the ones you want.
2. Or convert later with agy plugin import gemini. Extensions become Antigravity plugins and skills, and MCP servers move from settings.json into mcp_config.json.
3. Open mcp_config.json and change any remote server's url or httpUrl to serverUrl if the import did not.
4. Open /mcp and sign in again to servers that use OAuth.

Google says there is not one-to-one feature parity yet, so check each server's tools after the move rather than assuming they all came across.

A worked example: posting from Antigravity CLI

Skryvo is a remote MCP server for social media. In Antigravity CLI, add it to ~/.gemini/config/mcp_config.json:

{
  "mcpServers": {
    "skryvo": { "serverUrl": "https://api.skryvo.ai/mcp" }
  }
}

Open /mcp to sign in, then ask "Write a Bluesky post about our new docs and schedule it for Thursday at 2pm." It drafts the post in your brand's voice and Skryvo schedules it only after you approve. On Gemini CLI, gemini extensions install https://github.com/Skryvo/agent adds the same server. The Gemini setup page has both routes, and the same server works in Claude Code, Codex and Cursor.

If you are on a personal plan, move now: write your servers into mcp_config.json with serverUrl, import your extensions once, and check /mcp before trusting the move.