Built-In Browser Not Opening

Google Antigravity
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Hi there I am facing issue while opening the Antigravity Browser even the /browse open command is not working

Antigravity IDE

Antigravity IDE Version: 2.5.5
VSCode OSS Version: 1.107.0 (user setup)
Commit: ecfbad74d93962fc8ca485d93ab9b4f3d4cb****
Date: 2026-08-13T08:37:22.547Z (1 mo ago)
Electron: 39.2.3
Chromium: 142.0.7444.175
Node.js: 22.21.1
V8: 14.2.231.21-electron.0
OS: Windows_NT x64 10.0.19045
Language Server CL: 963923152

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Hi @engcountio,

Welcome to the Forum.

Thank you for sharing your Antigravity IDE (v2.5.5) and Windows 10 environment details.

Please follow these steps to resolve both the slash command and the built-in browser button not opening on Windows:

  1. Check Browser Settings & How to Trigger the Browser (Browser Overview & Slash Commands Docs):

    • Open User Settings > Browser and make sure Browser Tools is toggled ON.
    • Built-in slash commands like /browser (note: not /browse) are supported on Antigravity 2.0 and Antigravity CLI. In Antigravity IDE, you do not need a slash command—simply ask the agent in natural language (e.g., “Open http://localhost:3000 in the browser”), and it will automatically invoke the Browser Subagent.
    • Note that only localhost is pre-trusted by default in the Allowlist; for external URLs, click Always Allow when prompted in the chat panel.

  2. Fix the Built-In Browser Launch on Windows (HOME Variable & Playwright Driver):

    • On Windows, clicking the top-right browser icon can fail if the HOME environment variable is unset or if the initial Playwright 1.57.0 driver download returns 404 Not Found from the default mirror.

    • Make sure Google Chrome and Node.js are installed on your Windows machine, close Antigravity IDE completely, and run the following commands in PowerShell:

      powershell

      
\# 1. Set the HOME environment variable required on Windows

\[System.Environment\]::SetEnvironmentVariable('HOME', "$env:USERPROFILE", 'User')

\# 2. Bootstrap the Playwright 1.57.0 driver into your local cache

$D = "$env:LOCALAPPDATA\\ms-playwright-go\\1.57.0"

New-Item -ItemType Directory -Force -Path $D | Out-Null

curl.exe -sL "https://registry.npmjs.org/playwright-core/-/playwright-core-1.57.0.tgz" | tar.exe -xz -C $D

Copy-Item (Get-Command node).Source "$D\\node.exe" -Force

& "$D\\node.exe" "$D\\package\\cli.js" install chromium

    • Once complete, relaunch Antigravity IDE and click the Chrome browser icon in the top-right toolbar again.

If the browser still does not open after running these steps, please share either your diagnostic logs dumped in a .txt file (from Help > Toggle Developer Tools > Console) or an error screenshot so we can investigate further.