[VS Code Extension] Sidebar black screen / agy backend fails OAuth due to proxy & multi-NIC / TUN issues

Google Antigravity
,
1

This clearly indicates that traffic to Google OAuth endpoints is not being captured by the TUN interface and is leaking as direct connections.

Root Cause Analysis (after extensive debugging)

  1. agy backend has poor support for system proxy environment variables
    Setting HTTP_PROXY / HTTPS_PROXY / ALL_PROXY does not reliably make the Go-based agy process use the proxy.

  2. Using socks5:// protocol in environment variables breaks other tools (e.g. Claude Code / Node.js based extensions) with UnsupportedProxyProtocol errors.

  3. TUN mode leakage caused by:

    • Multiple virtual NICs (Hyper-V, WSL, VMware) competing for routing priority
    • Windows preferring IPv6, which often bypasses the TUN virtual adapter
    • xray TUN core having weaker compatibility with complex multi-NIC environments compared to sing-box

  4. Residual proxy environment variables also caused system-wide network issues (browser disconnection).

Final Working Solution

After long debugging, the following combination resolved the issue:

Action Details Purpose
Switch TUN core Change from xray to sing-box in v2rayN Tun settings Better compatibility with Hyper-V / VMware virtual adapters
Run as Administrator Completely exit v2rayN and relaunch as Administrator Ensure Wintun driver is properly created and activated
Disable IPv6 Uncheck “Internet Protocol Version 6 (TCP/IPv6)” on the physical WLAN adapter Prevent Windows from preferring IPv6 direct connections that leak past TUN
Clean environment variables Completely remove HTTP_PROXY, HTTPS_PROXY, ALL_PROXY, NO_PROXY from both User and System variables Avoid protocol conflicts with Node.js tools and residual pollution
Routing rules Set to “Bypass Mainland China” Google / Gemini traffic goes through proxy; domestic services stay direct

With the above configuration, the agy backend can successfully complete OAuth and the sidebar works normally. Other tools (Claude Code, etc.) also work without protocol errors.

Suggestions

  1. Improve the agy backend’s support for standard system proxy environment variables and common proxy software (especially TUN mode).
  2. Provide clearer error messages in the VS Code sidebar instead of a silent black screen when the local daemon fails to connect to Google services.
  3. Add official documentation about network requirements and recommended proxy configurations (especially for users behind restricted networks or complex multi-NIC setups).

Happy to provide more logs or additional details if needed.

Thank you!