[Bug Report] Agent Terminated with 500 Cascade Config Error on Gemini Models (Active Plan)

Google Antigravity
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1

Hi Antigravity Support Team,

I am experiencing a persistent issue where the AI Agent terminates immediately whenever I select any Gemini Model. However, the agent works completely fine when using Claude or ChatGPT models on the exact same project/session.

Account & System Status:

  • Account: Active subscription with available quota.

  • OS: macOS Apple Silicon (arm64)

  • IDE: Antigravity IDE

Issue Description: Every time a prompt is submitted using Gemini, the process fails instantly with an “agent terminated” notice. Checking the Developer Console (Cmd + Option + I), the local Language Server returns a 500 error failing to resolve the cascade config.

Console Error Logs:

Plaintext

127.0.0.1:49293/exa.language_server_pb.LanguageServerService/GetSlashCommands:1 Failed to load resource: the server responded with a status of 500 ()
Error fetching system slash commands: ConnectError: [unknown] failed to resolve cascade config: neither PlanModel nor RequestedModel specified. You must specify a valid model.

Troubleshooting already attempted:

  1. Signed out and re-authenticated the Google/Antigravity account in the IDE.

  2. Cleared local cache storage (rm -rf "$HOME/Library/Application Support/Antigravity IDE/User/globalStorage/state.vscdb"*).

  3. Created brand new agent sessions.

Since this issue occurs strictly on Gemini models while other providers work seamlessly, it appears to be a backend routing/mapping issue for Gemini models on my account tier.

Please help investigate and resolve this cascade mapping issue for my account.

2

Hi @Minh_Thi_n, Welcome to the Forum!

Could you please try these troubleshooting steps to resolve the issue:

Open the Command Palette (Ctrl+Shift+P or Cmd+Shift+P), run the command Antigravity: Reset onboarding, and complete the setup and login flow again.

Open the Command Palette, select Manage MCP Servers, disable all MCP servers, and restart the app. Re-enable them one by one to check if a specific server is causing the crash.

Do a Clean Reinstall (macOS)

  • Close Antigravity entirely.
  • Delete your local configuration folders to ensure a completely fresh start. Go to ~/Library/Application Support/. Find the Antigravity folder and move it to the Trash (also check for and delete ~/.config/Antigravity/ if it exists).
  • Uninstall the application by moving Antigravity from your Applications folder to the Trash.
  • Download the latest installer from the official website and reinstall.

Also, you can try temporarily switching to a different model (such as Gemini Flash) to see if that bypasses the error.

3

Thanks a lot! Turns out the main issue was my VPN. Thanks for the advice anyway!