Antigravity OAuth Plugin for OpenCode V2

Authenticate OpenCode V2 against Antigravity (Google's IDE backend) via OAuth and use Antigravity quota for gemini-3 / claude-4.6 models with your Google credentials. Multi-account rotation, thinking support, and session recovery included.

Maintained V2 port. This is a fork of NoeFabris/opencode-antigravity-auth (now archived), ported to the OpenCode V2 plugin API. Model requests flow through V2's AI SDK hook and the plugin's native engine (auth, transform, streaming, quota, rotation, recovery). Account files from earlier installs remain in use. Onboarding is opencode auth login (one account per run, up to 10); management is the /antigravity dialog (also Antigravity accounts in the command palette) over the credential-free AntigravityAccounts RPC. Server plugins have no toast API, so TUI toasts are emitted as plugin logs.

First release in preparation. [email protected] is not on npm yet. Use a local path below until the package is published; after release, use the registry entry shown below. The auto_update checker queries npm dist-tags and stays silent until publication.

What you get

• Gemini 3.6/3.7/3.8 Flash, Gemini 3.1 Pro, Claude Opus/Sonnet 4.6 Thinking, and GPT-OSS 120B Medium via Antigravity's Google OAuth
• Multi-account rotation across up to 10 Google accounts
• One Antigravity quota pool for supported models
• Gemini thinking variants for low/medium/high levels where supported
• Auto-recovery from interrupted tool calls
• Model-declared web search sanitized by the pipeline (no dedicated search tool is registered)

[!CAUTION] Terms of Service warning. This is an unofficial tool, not endorsed by Google. Proxying Antigravity may violate Google's Terms of Service; users have reported bans or shadow-bans. You assume all account, legal, and technical risk.

Installation

Until the first npm release, reference a local checkout. In your OpenCode config (~/.config/opencode/opencode.json or opencode.jsonc):

{
  "$schema": "https://opencode.ai/config.json",
  "plugins": ["/absolute/path/to/opencode-v2-antigravity-auth"],
}

Once 0.1.0 is published, replace the local path with a pinned registry entry:

{
  "$schema": "https://opencode.ai/config.json",
  "plugins": ["[email protected]"],
}

Local paths, file:// URLs, and registry packages with optional @version pins are accepted. The V2 key is plugins (plural).

opencode auth login   # one account per run; repeat to add more (max 10)

Then manage saved accounts inside OpenCode with /antigravity. The plugin registers a fixed model catalog — verify with:

opencode run "Hello" --model=antigravity/antigravity-gemini-3.8-flash

Multi-account in 30 seconds

• Add: opencode auth login — choose Add/reconnect before the browser opens (re-signing refreshes the same entry in place). Adds one account per command; rerun to add another (max 10), or press Ctrl+C to cancel. No custom host needed.
• Manage: /antigravity — saved quota bars, refresh-on-open and manual refresh (ctrl+r), enable/disable, verify with reconnect guidance, confirm-guarded removal.
• Details: docs/user/accounts-and-quota.md.

Configuration (optional)

Create ~/.config/opencode/antigravity.json (project override: .opencode/antigravity.json). Defaults work for most users.

| Area | Key options | | ----------------- | ------------------------------------------------------------------------------------------------------------ | | Thinking/recovery | keep_thinking (default false), session_recovery (true), auto_resume (false) | | Rotation | account_selection_strategy (hybrid), scheduling_mode (cache_first), pid_offset_enabled (false) | | Quota protection | soft_quota_threshold_percent (90), quota_refresh_interval_minutes (15) | | Behavior | quiet_mode (false), toast_scope (root_only), debug / debug_tui (false), auto_update (true) |

Full reference: docs/user/configuration.md. Schema: assets/antigravity.schema.json.

Gemini CLI-only model IDs such as gemini-2.5-pro and gemini-2.5-flash are not served through Antigravity OAuth. Use a registered antigravity-gemini-* model instead, or keep using those IDs with an ordinary Google API-key connection under OpenCode's separate google provider. Antigravity has its own provider and sign-in; this plugin does not change OpenCode's Google integration. Existing google/antigravity-* model references need the new antigravity/ provider prefix; saved plugin accounts remain in place. Verified Gemini preview aliases remain supported.

Docs

• User: installation · configuration · models & variants · accounts & quota · troubleshooting
• Developer: docs/dev/README.md (architecture, storage, RPC/TUI, quota contract, API, testing, manual checklist, maintainer ops)
• Normative specs: docs/specs/00-07 (agent/reviewer source of truth)
• Changelog

Development

Runtime tests stay beside their source under src/. Cross-cutting tests and smokes live under test/; build and repository tooling lives under scripts/. Run bun run test, bun run test:tui, bun run typecheck, and bun run lint before submitting changes. See developer testing for the suites and live-test requirements.

Compatibility

• Works alongside other plugins (oh-my-opencode, DCP). With oh-my-opencode, set "google_auth": false; list this plugin before DCP. No separate gemini-auth plugin is needed.
• Debug logs: OPENCODE_ANTIGRAVITY_DEBUG=1 (file) or =2/=verbose (verbose); OPENCODE_ANTIGRAVITY_DEBUG_TUI=1 shows logs in the TUI panel independently of file logging. See troubleshooting.

Credits

• Original plugin (V1, archived): NoeFabris/opencode-antigravity-auth
• opencode-gemini-auth by @jenslys
• CLIProxyAPI

License

MIT. See LICENSE. Not affiliated with Google. "Antigravity", "Gemini", "Google Cloud", and "Google" are trademarks of Google LLC.