Antigravity in Scient

Scient runs Google’s official Antigravity ACP agent and connects it to the account or credential method you select. The runtime, credentials, files, and conversation state stay on the environment that runs your project. Scient never asks for your Google password or silently substitutes another sign-in method.

For behavior shared by assisted providers, see Providers in Scient.

Assisted setup

Open Settings > Providers, select Antigravity, and choose Manage. The model picker can open the same compact setup flow. On mobile, open Settings > Environments and choose Set up Antigravity for the host environment.

1. If Antigravity is missing, choose Install Antigravity. Scient downloads the qualified official runtime into private app storage, checks the archive and executable, and activates it only after validation succeeds.
2. Choose Sign in with Google or Connect, according to the configured authentication method.
3. Complete the provider-owned flow. Scient then checks the account and loads the models available to it.

Installation and sign-in continue if you leave the setup surface. Background status checks never open a browser or start a sign-in flow.

Sign in from another device

Google returns to a 127.0.0.1 URL on the device running the browser. When the browser and provider environment are on different devices, that final page may not load. Expand Signing in on another computer?, copy the complete URL from the browser address bar, and paste it into Scient. Keep the query string and do not replace the host with the server address.

The response must match the current sign-in attempt. Other connected clients can see that setup is in progress. If the attempt expires, start a new one and use its new URL.

Authentication methods

The Antigravity provider settings select one of the methods exposed by the official agent:

Gemini Enterprise resolves access for its configured project and location. Agent Platform can use Application Default Credentials on the environment. Configured keys are stored in that environment’s provider settings and passed only to Antigravity. Ambient GEMINI_API_KEY and GOOGLE_* values do not silently change the selected method.

Changing the method stops that provider instance’s sessions. Disconnect or sign out before switching accounts.

Runtime ownership and updates

Scient supports both app-managed and existing installations:

• With Binary path empty, Scient prefers its verified managed ACP runtime, then looks for the official ACP executable on the environment’s PATH.
• An explicit ACP binary path takes priority. Its localharness_external helper must be beside it. Scient does not update or remove explicit or system installations.
• Existing legacy agy paths and conversations remain supported through the legacy transport. They are not reinterpreted as ACP sessions.

Managed ACP downloads are available on Apple Silicon macOS, x64 and ARM64 Linux, and x64 and ARM64 Windows. Google does not publish the ACP runtime for Intel macOS; existing legacy agy installations remain usable there, or the Mac can connect to a supported remote environment.

Scient’s update catalog treats official ACP and legacy agy as separate release families. When a newer ACP release has passed download, archive, native-startup, activation, and removal qualification on its supported target, Update Antigravity appears for managed ACP installations. An update keeps the previous generation available while active sessions finish. It never mutates a system or custom installation.

Repair Antigravity stages and validates a complete replacement before it touches a damaged managed generation. A failed download or verification leaves the existing copy and active pointer unchanged. Scient refuses to replace or remove a runtime while it is in use.

Models, files, and permissions

The official agent reports the models available to the selected account. Scient keeps the thread’s selected model when it resumes and asks for another selection if that model disappears. Older model generations remain available under Legacy models when the provider still offers them.

The model picker also refreshes when a running session reports new model choices. Models available in other Antigravity apps may not be available through the ACP agent.

For supported Gemini variants, choose the model once and use Reasoning to select an available level. On mobile, open Model and reasoning settings. Changing the level selects Google’s corresponding model variant; it does not change your account or installation. Saved favorites keep their exact model and reasoning level, so their labels still include the level.

Use Antigravity’s native /plan command to request a plan. Scient’s separate Plan mode control is unavailable when the protocol cannot support it.

Antigravity receives supported workspace files and message attachments through the ACP protocol, including images, PDFs, text, and audio. Its file edits, shell commands, and web actions use Scient’s normal permission surfaces. Provider questions with fixed choices remain interactive even in Full access. See Permission modes.

Antigravity does not support conversation rewind. Reverting a thread or editing and resubmitting an earlier turn is therefore unavailable; send a follow-up or start a new thread instead.

Skills and subagents

Project skills should use .agents/skills. Scient also discovers .gemini/skills and the legacy .agent/skills directory. For duplicate skill names, precedence is .gemini/skills, then .agents/skills, then .agent/skills.

Subagent launches appear as Antigravity subagent batch in Agents on web and desktop, and in the mobile work log. A launch can start several agents. The batch stays active while its parent turn runs, then becomes idle; launch errors remain visible. Google does not expose individual child status, names, models, usage, or reply ownership through ACP. A batch is not a separate controllable thread, and its launch description is not a child result.

Accounts, disabling, and removal

Each official ACP provider instance has a private profile, so multiple instances can use different accounts on one environment.

Legacy agy credentials use the older provider-owned credential store and are kept for legacy-session compatibility. Removing the ACP runtime does not erase that external credential store.

Disconnect does not erase API keys saved in provider settings or Application Default Credentials managed outside Scient. Remove those separately if you no longer want that credential method available.

Troubleshooting

Health checks, model refresh, and sign-out allow up to 90 seconds for the official runtime to start, which can be slow on some computers. Explicit refresh uses saved credentials and does not launch a login page. Automatic checks verify installation only. Google controls account eligibility and limits; Scient does not silently switch authentication methods to bypass an account restriction.

• Antigravity is missing: install the managed runtime, use an official system installation, or set its absolute binary path.
• Sign-in did not open: retry from the explicit setup action. Passive refreshes intentionally do not launch a browser.
• Remote sign-in stopped at localhost: paste the full return URL through the collapsed remote-device control.
• Credentials are incomplete: return to provider configuration and supply the key, project, or location required by the selected method.
• Connected but no models: refresh provider status. Google controls account eligibility, models, subscriptions, and limits.
• Managed runtime is damaged: choose Repair Antigravity. If sessions are active, stop them first and retry.

The official ACP registry is available at agentclientprotocol/registry.