opencode-antigravity-auth

Antigravity auth, account management, quota inspection, runtime metadata extraction, and bridge support for OpenCode.

This is one of the best-maintained Antigravity plugins for OpenCode. The focus is simple: stay as close as possible to the real installed Antigravity app instead of hardcoding brittle request behavior.

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Important

The Antigravity language server and headless bridge path is the most stable way to use Antigravity from OpenCode. If you want the behavior closest to the IDE, use the installed Antigravity app and let this plugin read its runtime metadata and language server binaries. Looser request-only paths drift faster, hit rate limits sooner, and are more likely to cause account-state problems or bans.

What This Plugin Does

• Google OAuth login for Antigravity-compatible accounts
• Multi-account storage, rotation, quota inspection, and verification
• Runtime metadata extraction from the installed Antigravity app
• Bridge support for the Antigravity language server and headless flows
• Runtime model discovery with safe fallback catalogs
• /ag-accounts TUI for account management inside OpenCode

Requirements

• Windows is the primary supported path for the Antigravity bridge and local app discovery
• Node.js 20+
• Bun available if you want to run the local helper commands exactly as documented below
• An installed Antigravity app if you want runtime metadata extraction and the most stable bridge behavior

Default installed Antigravity app root on Windows:

C:\Users\<you>\AppData\Local\Programs\Antigravity\resources\app

Quick Start

Stock OpenCode setup

For the stock GitHub/OpenCode release, the safest mental model is:

• opencode.json loads the server plugin
• tui.json loads the TUI plugin
• bridge-backed models only work if the root server plugin is loaded correctly

If you only add the TUI side, /ag-accounts can appear while model requests still fail.

If the package is installed through OpenCode's plugin installer, OpenCode can detect both the server and TUI targets from this package and patch the right config files automatically.

1. Clone and install

git clone https://github.com/vibheksoni/opencode-antigravity-auth.git
cd opencode-antigravity-auth
npm install
npm run build

2. Add the plugin to OpenCode

Use the active opencode.json or opencode.jsonc.

Common locations:

• project-local: <workspace>\.opencode\opencode.json
• custom config dir: %OPENCODE_CONFIG_DIR%\opencode.json
• default user config: %USERPROFILE%\.config\opencode\opencode.json

Local development example:

{
  "plugin": [
    [
      "C:\\absolute\\path\\to\\opencode-antigravity-auth",
      {
        "force_headless": true,
        "cleanup_on_exit": true,
        "debug": true
      }
    ]
  ]
}

Published plugin example:

{
  "plugin": [
    [
      "opencode-antigravity-auth@latest",
      {
        "force_headless": true,
        "cleanup_on_exit": true
      }
    ]
  ]
}

Recommended manual config for stock OpenCode:

opencode.json

{
  "plugin": [
    [
      "C:\\absolute\\path\\to\\opencode-antigravity-auth",
      {
        "force_headless": true,
        "cleanup_on_exit": true,
        "debug": false
      }
    ]
  ]
}

Default tuple plugin behavior when these values are omitted:

• force_headless: true
• cleanup_on_exit: true
• debug: false
• single_headless: false
• app_dir: auto-detect from the installed Antigravity app

3. Add the TUI plugin on newer OpenCode versions

Current OpenCode splits server plugins and TUI plugins.

That means the slash commands and account UI do not come from the main server plugin entry. They come from the separate TUI entry.

That means:

• opencode-antigravity-auth handles the server/auth/runtime side
• opencode-antigravity-auth/tui handles slash commands and the account manager UI

If bun run account -- list works but /ag-accounts does not appear, the usual cause is that the TUI plugin was never added to tui.json, or the TUI config points at the package root instead of the explicit /tui entry.

Use the active tui.json.

Common locations:

• project-local: <workspace>\.opencode\tui.json
• custom config dir: %OPENCODE_CONFIG_DIR%\tui.json
• default user config: %USERPROFILE%\.config\opencode\tui.json

Installed plugin example:

{
  "plugin": [
    "opencode-antigravity-auth/tui"
  ]
}

Recommended manual config for stock OpenCode:

tui.json

{
  "plugin": [
    "C:\\absolute\\path\\to\\opencode-antigravity-auth/tui"
  ]
}

Local path example for current OpenCode:

{
  "plugin": [
    "C:\\absolute\\path\\to\\opencode-antigravity-auth/tui"
  ]
}

If your environment prefers backslashes in the path portion, this also works:

{
  "plugin": [
    "C:\\absolute\\path\\to\\opencode-antigravity-auth\\tui"
  ]
}

Important:

• put the server plugin in opencode.json
• put the TUI plugin in tui.json
• for the TUI side, prefer the explicit /tui entry instead of the package root
• do not point opencode.json at /tui
• do not point tui.json at the package root unless your local setup explicitly requires it

After adding the TUI entry, restart OpenCode and then use:

• /ag-accounts
• /ag

4. Optional runtime config

This plugin also reads its own config file:

• project-local: <workspace>\.opencode\antigravity.json
• user-level: %OPENCODE_CONFIG_DIR%\antigravity.json or %USERPROFILE%\.config\opencode\antigravity.json

Example:

{
  "debug": true,
  "debug_tui": false,
  "keep_thinking": false,
  "session_recovery": true,
  "auto_resume": false,
  "account_selection_strategy": "hybrid",
  "scheduling_mode": "cache_first",
  "quota_refresh_interval_minutes": 15
}

5. Start OpenCode and authenticate

opencode
opencode auth login

Choose:

1. Provider: google
2. Method: OAuth with Google (Antigravity)
3. OAuth client: Standard or GCP ToS

6. Open the account manager

Inside OpenCode use:

• /ag-accounts
• /ag

From there you can:

• add accounts
• verify accounts
• check quotas
• inspect per-account details
• write model definitions into opencode.json
• tune load balancer settings

TUI Setup Notes

For current OpenCode releases, the separate TUI entry is important:

• server plugin spec: opencode-antigravity-auth
• TUI plugin spec: opencode-antigravity-auth/tui

For local path installs:

• server plugin path: C:\path\to\opencode-antigravity-auth
• TUI plugin path: C:\path\to\opencode-antigravity-auth\tui

Without the TUI plugin entry:

• the standalone helper can still work
• auth/runtime behavior may still exist
• but /ag-accounts and other TUI-side commands will not load

What this looks like in practice:

• opencode.json loads the auth/provider/bridge logic
• tui.json loads the slash commands, dialogs, and account manager

If you only configure the root package and skip the /tui entry, the plugin can look partially installed while the UI commands still never appear.

Bridge Model Notes

Bridge-backed models such as:

• antigravity-server-bridge/antigravity-bridge-claude-sonnet-4.6-thinking
• antigravity-server-bridge/antigravity-bridge-gemini-3-flash

depend on the root server plugin being loaded successfully.

If the root server plugin is missing or misconfigured, you can end up with a visible bridge provider but no runtime bridge URL, which leads to OpenCode errors like:

"undefined/chat/completions" cannot be parsed as a URL.

If you see that:

• verify the root plugin is present in opencode.json
• verify the TUI entry is separate in tui.json
• fully restart OpenCode after changing plugin config

Recommended Windows Setup

If Antigravity is installed in the default Windows location, this is usually enough:

{
  "plugin": [
    [
      "opencode-antigravity-auth@latest"
    ]
  ]
}

If your Antigravity install lives elsewhere, add app_dir:

{
  "plugin": [
    [
      "opencode-antigravity-auth@latest",
      {
        "app_dir": "C:\\Users\\<you>\\AppData\\Local\\Programs\\Antigravity\\resources\\app",
        "force_headless": true,
        "cleanup_on_exit": true,
        "debug": true
      }
    ]
  ]
}

Config Sources

There are two separate config layers:

OpenCode tuple plugin options

These live in opencode.json or opencode.jsonc and control plugin registration plus bridge-oriented runtime options.

Useful tuple options:

• app_dir
• debug
• log_dir
• force_headless
• single_headless
• cleanup_on_exit
• bridge.force_headless
• bridge.single_headless
• bridge.cleanup_on_exit
• bridge.debug
• bridge.log_dir
• bridge.app_dir

If you do not set them, the bridge defaults are:

• force_headless: true
• cleanup_on_exit: true
• debug: false
• single_headless: false

antigravity.json

This is the plugin's own runtime config file and controls behavior such as:

• keep_thinking
• session_recovery
• auto_resume
• resume_text
• account_selection_strategy
• scheduling_mode
• quota_refresh_interval_minutes
• soft_quota_threshold_percent
• cli_first
• auto_update

Bridge and LS Server Behavior

Bridge mode uses the installed Antigravity app to discover:

• runtime version
• OAuth client IDs and secrets
• language server binaries

Windows language server binaries are expected under:

<app_dir>\extensions\antigravity\bin

If the standard app install exists, you usually do not need to configure anything else.

If you want the bridge to prefer a specific installed client or binary:

• set tuple option app_dir
• or set OPENCODE_ANTIGRAVITY_APP_DIR
• or set CODEIUM_LANGUAGE_SERVER_BIN to a specific language server binary

Standalone Account Helper

After building, you can use the standalone helper:

bun run account
bun run account -- add
bun run account -- add --no-browser
bun run account -- add --gcp-tos
bun run account -- list
bun run account -- clear

Environment Variables Actually Read by Runtime

These are the environment variables the code actually reads today.

Core plugin runtime

• OPENCODE_ANTIGRAVITY_APP_DIR
• OPENCODE_ANTIGRAVITY_CLIENT_ID
• OPENCODE_ANTIGRAVITY_CLIENT_SECRET
• OPENCODE_ANTIGRAVITY_GCP_TOS_CLIENT_ID
• OPENCODE_ANTIGRAVITY_GCP_TOS_CLIENT_SECRET
• OPENCODE_ANTIGRAVITY_GCP_TOS
• OPENCODE_ANTIGRAVITY_OAUTH_BIND
• OPENCODE_ANTIGRAVITY_DEBUG
• OPENCODE_ANTIGRAVITY_DEBUG_TUI
• OPENCODE_ANTIGRAVITY_CONSOLE_LOG

Bridge and headless runtime

• OPENCODE_ANTIGRAVITY_BRIDGE_FORCE_HEADLESS
• OPENCODE_ANTIGRAVITY_BRIDGE_DEBUG
• OPENCODE_ANTIGRAVITY_BRIDGE_DEBUG_HEADLESS
• OPENCODE_ANTIGRAVITY_BRIDGE_BASE_URL
• CODEIUM_LANGUAGE_SERVER_BIN

OpenCode pathing and auth storage

• OPENCODE_CONFIG_DIR
• OPENCODE_GLOBAL_DATA_DIR

Other runtime knobs

• OPENCODE_IMAGE_ASPECT_RATIO

Important nuance:

• quiet_mode, toast_scope, log_dir, account_selection_strategy, scheduling_mode, and similar knobs are runtime config keys
• some source comments still mention env overrides for those keys
• the list above is the set of env vars actually read directly by runtime code today

Debug Logs

Debug files go under:

• %OPENCODE_CONFIG_DIR%\antigravity-logs when OPENCODE_CONFIG_DIR is set
• otherwise %USERPROFILE%\.config\opencode\antigravity-logs

The TUI config writer and /ag-accounts actions now also respect OPENCODE_CONFIG_DIR, so source-mode and wrapper launches update the same config root the runtime is using.

Useful markers in the debug logs:

• tui-init
• tui-quota-open
• tui-quota-results
• token-refresh-start
• token-refresh-success
• token-refresh-interop-fallback
• quota-check-error
• bridge-headless-started
• bridge-account-selected
• bridge-chat-success

Configure Models from the TUI

/ag-accounts -> Configure models writes plugin model definitions into the active OpenCode config file.

That action now respects:

1. OPENCODE_CONFIG_DIR
2. existing opencode.jsonc
3. existing opencode.json

It will not silently write to the wrong config root when you are launching OpenCode from a custom wrapper or source checkout.

Build and Test

Build:

npm run build

Regenerate schema:

npm run build:schema

Run tests:

npm test

Run targeted tests:

npm test -- --run src/plugin/token.test.ts src/plugin/quota.test.ts src/plugin/logger.test.ts src/plugin/debug.test.ts
npm test -- --run src/plugin/config/schema.test.ts src/plugin/config/updater.test.ts src/bridge/options.test.ts

Current Notes

• The plugin tries to extract runtime metadata from the local app first, then falls back cleanly
• Model discovery can fail with live 403 responses on some accounts, so static fallback models remain important
• Quota inspection merges Antigravity buckets with Gemini CLI quota reporting
• The bridge keeps a headless fallback path because it matches the IDE more closely than direct request emulation

Acknowledgements

Credit to the original work at NoeFabris/opencode-antigravity-auth.

This repo has diverged significantly from that older implementation and continues to be maintained around the current Antigravity app behavior, Windows bridge support, runtime metadata extraction, quota tooling, and OpenCode integration.