Install, authenticate, verify, and run the Antigravity CLI through Tejus on Windows.

Tejus connects to Google's Antigravity CLI through the agy executable. For each turn it runs agy in print mode and reads its streamed output. Antigravity owns its account session, models, tools, and conversation runtime; Tejus supplies the task boundary, working environment, transcript, browser, terminal, diff, and Git workflow around it.

Install

Install the CLI with Google's official Windows installer from PowerShell:

irm https://antigravity.google/cli/install.ps1 | iex

Tejus needs Antigravity CLI 1.0.12 or newer. Verify the executable from a new PowerShell window:

agy --version

Authenticate

In Tejus, open Settings → Agent providers, expand Antigravity under Provider tools, and click Sign in; Tejus starts agy in a terminal window. Follow Antigravity's sign-in prompts; your browser or the Windows credential store may ask for approval. You can also start it yourself:

agy

To remove stored credentials from an interactive Antigravity session, use:

/logout

Tejus does not copy or replace the credentials stored by Antigravity.

Verify

From a clean test folder:

mkdir $env:TEMP\agy-tejus-check
cd $env:TEMP\agy-tejus-check
agy models
agy

agy models should list the models your account can use; Tejus runs the same command to confirm that you are signed in. Then confirm that Antigravity starts without a sign-in error and can answer a harmless read-only request. Exit before making changes.

Connect to Tejus

Enable Antigravity

Open Settings → Agent providers, keep Antigravity enabled under Provider activity, and click Refresh status. A ready status reads “Antigravity CLI is installed, authenticated, and returned available models.”

Check the executable path

Use automatic discovery unless you intentionally installed Antigravity elsewhere. Antigravity binary path (in Antigravity's Runtime section under Provider tools) must point to the executable itself.

Select Full access

Antigravity's print mode cannot pause for interactive approvals, so Tejus only starts Antigravity tasks in the Full access permission mode. Other modes fail with “Antigravity CLI print mode cannot pause for interactive approvals. Select Full access to use this provider.” Use a repository you are comfortable letting the agent change freely, or a worktree.

Start a bounded task

Use a clean repository and a small objective. Review the selected model, effort, and working environment before sending the first turn.

Capabilities in Tejus

Antigravity sessions can expose:

Models discovered from agy models, with Low, Medium, High, or Thinking effort where a model offers them
Assistant output, command execution, file changes, and web-search and browser activity
Attachments passed to the provider as files
Conversation continuity across turns, including subagent conversations
Tejus's terminal, browser, diff, checkpoint, and Git delivery surfaces

Changing the model restarts the Antigravity session. Context compaction and live steering of a running turn are not supported.

To follow conversations, Tejus installs a small hook plugin into Antigravity (tejus-capture, under %USERPROFILE%\.gemini\antigravity-cli\plugins\).

Antigravity keeps its own settings and conversation data. Changes to its model, hooks, or workspace trust can alter behavior even when the same task is opened through Tejus.

Prompt length on Windows

Antigravity takes print-mode prompts as command-line arguments, so on Windows Tejus limits a prompt to 24,000 characters. For longer content, attach it as files instead.

Updating

Antigravity manages its own releases:

agy update

Tejus cannot tell whether a newer version exists, so the Update action sits inside Antigravity's row under Settings → Agent providers → Provider tools and runs agy update for you. Keep the installation folder writable by your user and restart Tejus after the executable changes.

Troubleshooting

Antigravity is not detected

Tejus shows “Antigravity CLI (agy) is not installed or is not on PATH.”

Run agy --version from a new PowerShell window.
Confirm the installation folder is on PATH.
Clear or correct an obsolete custom binary path in Tejus.
Restart Tejus after installation or PATH changes.

Antigravity