Google Antigravity Setup

Overview

Google Antigravity is Google's agent-first development environment — an IDE, CLI, and SDK built around Gemini models. It replaced Gemini CLI as the consumer path in June 2026, and it treats MCP servers as first-class: add Tempreon once and every Antigravity agent can use it.

Connecting Tempreon gives those agents persistent intelligence: your AI loads your Core Imprint, searches your Knowledge Vault for context, and remembers what it learns — and because Tempreon is one shared layer, that memory follows you across every other connected tool.

As of September 2026, Antigravity is generally available, and there is a free tier for individuals alongside paid Google AI Pro and Ultra plans that raise the usage quota. MCP setup works the same way on each.

Quick path: add Tempreon to ~/.gemini/config/mcp_config.json with a serverUrl entry → Agent Settings → Customizations → Authenticate → approve in the browser → copy the authorization code back → Submit.

Prerequisites

• Google Antigravity installed (IDE or CLI) and signed in with your Google account
• A Tempreon account with at least one available Bridge slot
• A browser for the authorization step

Step-by-Step Setup

1. Add Tempreon to the MCP config

Antigravity reads MCP servers from a JSON config file:

• Global (all projects): ~/.gemini/config/mcp_config.json
• Workspace (one project): .agents/mcp_config.json in the project root

Add Tempreon using the serverUrl field:

{
  "mcpServers": {
    "tempreon": {
      "serverUrl": "https://api.tempreon.com/functions/v1/tempreon-mcp/mcp"
    }
  }
}

Use serverUrl. It's the field Antigravity's docs specify, it works on every build, and it's the single key for both Streamable HTTP and SSE. Don't depend on other field names: Antigravity's documentation lists url and httpUrl as unsupported, and although a CLI changelog entry did mention accepting url, Google's own sources disagree on that point — serverUrl is the one that holds up everywhere. If the server never shows up, the field name is the first thing to check. (If you're migrating a config from Gemini CLI, which uses httpUrl, rename the field.)

The URL is also shown in your Bridges dashboard. You don't need a token, API key, or client ID — Tempreon supports dynamic client registration, so OAuth is zero-config.

2. Authenticate

1. In Antigravity, open Agent Settings → Customizations
2. Find the tempreon server and select Authenticate
3. A browser tab opens to Tempreon's consent screen — sign in to your Tempreon account and approve
4. The browser then shows an authorization code. Copy it — this is a paste-back flow, not an automatic redirect. If you close the tab without copying, restart from Authenticate
5. Return to Antigravity, paste the code, and select Submit

Tokens are stored at ~/.gemini/antigravity/mcp_oauth_tokens.json.

3. Verify the connection

In the Antigravity CLI, run /mcp to check server status. In the IDE, ask an agent "What Tempreon tools do you have access to?" — if it answers with a list, the Bridge is live.

Troubleshooting

The server never appears, or the config is rejected. Check the field name. Use serverUrl — it works on every build and is what Antigravity's docs specify. httpUrl (the Gemini CLI key) is listed as unsupported here; rename it to serverUrl.

Connection fails immediately. Confirm the URL ends in /mcp with no trailing slash: https://api.tempreon.com/functions/v1/tempreon-mcp/mcp.

You approved in the browser but Antigravity still shows the server as unauthenticated. The flow isn't done at approval — copy the authorization code from the browser, paste it back in Antigravity, and select Submit.

Authentication keeps failing. Run the Authenticate flow again from Agent Settings → Customizations. Stored tokens live at ~/.gemini/antigravity/mcp_oauth_tokens.json.

Coming from Gemini CLI? Google stopped serving Gemini CLI for consumer accounts on June 18, 2026 — Antigravity is the replacement. The config formats differ (serverUrl here, httpUrl there), so re-create the entry rather than copying it across.

Also connect: Gemini App · Gemini CLI · Any MCP Client

Try saying...

• "Start my session." — triggers session_start to load your Core Imprint
• "Search my knowledge base for [topic] before we plan this change." — pulls your Knowledge Vault into the agent's context
• "Remember that [decision] — we chose it because [reason]." — stores the insight for every future session, in every connected tool