Google Antigravity's agent-first IDE struggles with Pro authentication on Windows 10 using WSL2. The core issue is a broken authentication handshake between the Linux terminal and Windows browser, often due to WSL2's virtualized networking. Symptoms include loading screens, invalid token errors, and failed `agy` commands, blocking access to Gemini 3 Pro models.

The fix requires configuring WSL2's mirrored networking mode via `.wslconfig` to expose local ports. Synchronizing the system clock is also critical, as OAuth 2.0 rejects tokens from drifted WSL clocks. Account eligibility matters—personal Gmail accounts work best, while Workspace accounts may need admin approval for experimental services.

Missing WSL extension scripts are a known bug. You must manually extract them from the VS Code Marketplace, update the launcher's `WSL_EXT_ID`, and create a wrapper script to bridge WSL-to-Windows commands. Enabling WSL interop in `wsl.conf` ensures the `agy` binary executes properly from Ubuntu.

Once configured, you can run `agy` commands to analyze codebases with a 1M+ token context. The effort unlocks powerful AI agents directly in your WSL environment, though regional consistency and avoiding VPNs during sign-in are recommended for a seamless experience.