rishav-antigravity-auth

v1.2.9

Published

23 days ago

Google Antigravity IDE OAuth auth plugin for Opencode - access Gemini 3 Pro and Claude 4.5 using Google credentials (Fixed rate limit rotation)

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irishavmishra

opencode google antigravity gemini oauth plugin auth claude

Antigravity + Gemini CLI OAuth Plugin for Opencode

🔧 Fixed Fork: This is a fork of opencode-antigravity-auth with multi-account rotation bug fixes. Issues #134, #135, and #136 are resolved - accounts now properly rotate when rate-limited instead of repeatedly using the same account.

Enable Opencode to authenticate against Antigravity (Google's IDE) via OAuth so you can use Antigravity rate limits and access models like gemini-3-pro-high and claude-opus-4-5-thinking with your Google credentials.

What you get

Google OAuth sign-in with automatic token refresh via opencode auth login
Dual Quota System - Access both Antigravity quota (Claude, Gemini 3) and Gemini CLI quota from a single plugin
Multi-Account Rotation - Add multiple Google accounts; automatically rotates when one is rate-limited
Real-time SSE streaming including thinking blocks and incremental output
Extended Thinking - Native support for Claude thinking budgets and Gemini 3 thinking levels
Auto Recovery - Automatic session recovery from Claude tool_result_missing errors
Plugin Compatible - Works alongside other OpenCode plugins (opencodesync, etc.)

Installation

For Humans

Option A: Let an LLM do it

Paste this into any LLM agent (Claude Code, OpenCode, Cursor, etc.):

Install the rishav-antigravity-auth plugin (fixed fork with proper account rotation) and add the Antigravity model definitions to ~/.config/opencode/opencode.json by following: https://raw.githubusercontent.com/irishavmishra/opencode-antigravity-auth/main/README.md

Option B: Manual setup

Add the plugin to your config (~/.config/opencode/opencode.json):
```
{
  "plugin": ["[email protected]"]
}
```
Authenticate:
```
opencode auth login
```

Add models (see Available Models for full list):

{
  "plugin": ["[email protected]"],
  "provider": {
    "google": {
      "models": {
        "antigravity-claude-sonnet-4-5": {
          "name": "Claude Sonnet 4.5 (Antigravity)",
          "limit": { "context": 200000, "output": 64000 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        }
      }
    }
  }
}

Use it:

opencode run "Hello" --model=google/antigravity-claude-sonnet-4-5

Step-by-Step Instructions

Edit the OpenCode configuration file:
- Linux/Mac: ~/.config/opencode/opencode.json
- Windows: %APPDATA%\opencode\opencode.json
Add the plugin to the plugins array
Set provider to "google" and choose a model

Complete Configuration Example

Create ~/.config/opencode/opencode.json:

{
  "$schema": "https://opencode.ai/config.json",
  "plugin": ["[email protected]"],
  "provider": {
    "google": {
      "models": {
        "antigravity-gemini-3-pro-low": {
          "name": "Gemini 3 Pro Low (Antigravity)",
          "limit": { "context": 1048576, "output": 65535 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        },
        "antigravity-gemini-3-pro-high": {
          "name": "Gemini 3 Pro High (Antigravity)",
          "limit": { "context": 1048576, "output": 65535 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        },
        "antigravity-gemini-3-flash": {
          "name": "Gemini 3 Flash (Antigravity)",
          "limit": { "context": 1048576, "output": 65536 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        },
        "gemini-3-pro-low": {
          "name": "Gemini 3 Pro Low (Gemini)",
          "limit": { "context": 1048576, "output": 65535 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        },
        "gemini-3-pro-high": {
          "name": "Gemini 3 Pro High (Gemini)",
          "limit": { "context": 1048576, "output": 65535 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        },
        "gemini-3-flash": {
          "name": "Gemini 3 Flash (Gemini)",
          "limit": { "context": 1048576, "output": 65536 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        },
        "antigravity-claude-sonnet-4-5": {
          "name": "Claude Sonnet 4.5 (Antigravity)",
          "limit": { "context": 200000, "output": 64000 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        },
        "antigravity-claude-sonnet-4-5-thinking-low": {
          "name": "Claude Sonnet 4.5 Low (Antigravity)",
          "limit": { "context": 200000, "output": 64000 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        },
        "antigravity-claude-sonnet-4-5-thinking-medium": {
          "name": "Claude Sonnet 4.5 Medium (Antigravity)",
          "limit": { "context": 200000, "output": 64000 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        },
        "antigravity-claude-sonnet-4-5-thinking-high": {
          "name": "Claude Sonnet 4.5 High (Antigravity)",
          "limit": { "context": 200000, "output": 64000 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        },
        "antigravity-claude-opus-4-5-thinking-low": {
          "name": "Claude Opus 4.5 Low (Antigravity)",
          "limit": { "context": 200000, "output": 64000 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        },
        "antigravity-claude-opus-4-5-thinking-medium": {
          "name": "Claude Opus 4.5 Medium (Antigravity)",
          "limit": { "context": 200000, "output": 64000 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        },
        "antigravity-claude-opus-4-5-thinking-high": {
          "name": "Claude Opus 4.5 High (Antigravity)",
          "limit": { "context": 200000, "output": 64000 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        }
      }
    }
  }
}

Verification

opencode run "Hello" --model=google/antigravity-claude-sonnet-4-5

Available Models

Antigravity Quota

Models with antigravity- prefix use Antigravity quota:

| Model | Description | |-------|-------------| | google/antigravity-gemini-3-flash | Gemini 3 Flash (minimal thinking) | | google/antigravity-gemini-3-pro-low | Gemini 3 Pro with low thinking | | google/antigravity-gemini-3-pro-high | Gemini 3 Pro with high thinking | | google/antigravity-claude-sonnet-4-5 | Claude Sonnet 4.5 (no thinking) | | google/antigravity-claude-sonnet-4-5-thinking-low | Sonnet with 8K thinking budget | | google/antigravity-claude-sonnet-4-5-thinking-medium | Sonnet with 16K thinking budget | | google/antigravity-claude-sonnet-4-5-thinking-high | Sonnet with 32K thinking budget | | google/antigravity-claude-opus-4-5-thinking-low | Opus with 8K thinking budget | | google/antigravity-claude-opus-4-5-thinking-medium | Opus with 16K thinking budget | | google/antigravity-claude-opus-4-5-thinking-high | Opus with 32K thinking budget |

Backward compatibility: Old model names (gemini-3-pro-low, gemini-3-pro-high, gemini-3-flash) still work as a fallback. However, you should update to the antigravity- prefix for stability. See Migration Guide.

Gemini CLI Quota

Models with -preview suffix use Gemini CLI quota:

| Model | Description | |-------|-------------| | google/gemini-2.5-flash | Gemini 2.5 Flash | | google/gemini-2.5-pro | Gemini 2.5 Pro | | google/gemini-3-flash-preview | Gemini 3 Flash (preview) | | google/gemini-3-pro-preview | Gemini 3 Pro (preview) |

{
  "$schema": "https://opencode.ai/config.json",
  "plugin": ["[email protected]"],
  "provider": {
    "google": {
      "models": {
        "antigravity-gemini-3-pro-low": {
          "name": "Gemini 3 Pro Low (Antigravity)",
          "limit": { "context": 1048576, "output": 65535 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        },
        "antigravity-gemini-3-pro-high": {
          "name": "Gemini 3 Pro High (Antigravity)",
          "limit": { "context": 1048576, "output": 65535 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        },
        "antigravity-gemini-3-flash": {
          "name": "Gemini 3 Flash (Antigravity)",
          "limit": { "context": 1048576, "output": 65536 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        },
        "gemini-3-pro-low": {
          "name": "Gemini 3 Pro Low (Antigravity)",
          "limit": { "context": 1048576, "output": 65535 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        },
        "gemini-3-pro-high": {
          "name": "Gemini 3 Pro High (Antigravity)",
          "limit": { "context": 1048576, "output": 65535 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        },
        "gemini-3-flash": {
          "name": "Gemini 3 Flash (Antigravity)",
          "limit": { "context": 1048576, "output": 65536 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        },
        "antigravity-claude-sonnet-4-5": {
          "name": "Claude Sonnet 4.5 (Antigravity)",
          "limit": { "context": 200000, "output": 64000 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        },
        "antigravity-claude-sonnet-4-5-thinking-low": {
          "name": "Claude Sonnet 4.5 Think Low (Antigravity)",
          "limit": { "context": 200000, "output": 64000 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        },
        "antigravity-claude-sonnet-4-5-thinking-medium": {
          "name": "Claude Sonnet 4.5 Think Medium (Antigravity)",
          "limit": { "context": 200000, "output": 64000 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        },
        "antigravity-claude-sonnet-4-5-thinking-high": {
          "name": "Claude Sonnet 4.5 Think High (Antigravity)",
          "limit": { "context": 200000, "output": 64000 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        },
        "antigravity-claude-opus-4-5-thinking-low": {
          "name": "Claude Opus 4.5 Think Low (Antigravity)",
          "limit": { "context": 200000, "output": 64000 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        },
        "antigravity-claude-opus-4-5-thinking-medium": {
          "name": "Claude Opus 4.5 Think Medium (Antigravity)",
          "limit": { "context": 200000, "output": 64000 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        },
        "antigravity-claude-opus-4-5-thinking-high": {
          "name": "Claude Opus 4.5 Think High (Antigravity)",
          "limit": { "context": 200000, "output": 64000 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        },
        "gemini-2.5-flash": {
          "name": "Gemini 2.5 Flash (CLI)",
          "limit": { "context": 1048576, "output": 65536 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        },
        "gemini-2.5-pro": {
          "name": "Gemini 2.5 Pro (CLI)",
          "limit": { "context": 1048576, "output": 65536 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        },
        "gemini-3-flash-preview": {
          "name": "Gemini 3 Flash Preview (CLI)",
          "limit": { "context": 1048576, "output": 65536 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        },
        "gemini-3-pro-preview": {
          "name": "Gemini 3 Pro Preview (CLI)",
          "limit": { "context": 1048576, "output": 65535 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        }
      }
    }
  }
}

Multi-Account Setup

Add multiple Google accounts for higher combined quotas. The plugin automatically rotates between accounts when one is rate-limited.

opencode auth login

Load Balancing Behavior

Sticky account selection - Sticks to the same account until rate-limited (preserves Anthropic's prompt cache)
Per-model-family limits - Rate limits tracked separately for Claude and Gemini models
Dual quota pools for Gemini - Automatic fallback between Antigravity quota and Gemini CLI quota before switching accounts
Smart retry threshold - Short rate limits (≤5s) are retried on same account
Exponential backoff - Increasing delays for consecutive rate limits

Dual Quota Pools (Gemini only)

For Gemini models, the plugin accesses two independent quota pools per account:

| Quota Pool | When Used | |------------|-----------| | Antigravity | Primary (tried first) | | Gemini CLI | Fallback when Antigravity is rate-limited |

This effectively doubles your Gemini quota per account.

Adding Accounts

When running opencode auth login with existing accounts:

2 account(s) saved:
  1. [email protected]
  2. [email protected]

(a)dd new account(s) or (f)resh start? [a/f]:

Account Storage

Stored in ~/.config/opencode/antigravity-accounts.json
Contains OAuth refresh tokens - treat like a password
If Google revokes a token (invalid_grant), that account is automatically removed

Configuration

Create ~/.config/opencode/antigravity.json (or .opencode/antigravity.json in project root):

General Settings

| Option | Default | Description | |--------|---------|-------------| | quiet_mode | false | Suppress toast notifications (except recovery) | | debug | false | Enable debug logging to file | | log_dir | OS default | Custom directory for debug logs | | auto_update | true | Enable automatic plugin updates |

Session Recovery

| Option | Default | Description | |--------|---------|-------------| | session_recovery | true | Auto-recover from tool_result_missing errors | | auto_resume | true | Auto-send resume prompt after recovery | | resume_text | "continue" | Text to send when auto-resuming |

Error Recovery

| Option | Default | Description | |--------|---------|-------------| | empty_response_max_attempts | 4 | Retries for empty API responses | | empty_response_retry_delay_ms | 2000 | Delay between retries | | tool_id_recovery | true | Fix mismatched tool IDs from context compaction | | claude_tool_hardening | true | Prevent tool parameter hallucination |

Token Management

| Option | Default | Description | |--------|---------|-------------| | proactive_token_refresh | true | Refresh tokens before expiry | | proactive_refresh_buffer_seconds | 1800 | Refresh 30min before expiry | | max_rate_limit_wait_seconds | 300 | Max wait time when rate limited (0=unlimited) | | quota_fallback | false | Try alternate quota when rate limited |

Environment Overrides

OPENCODE_ANTIGRAVITY_QUIET=1         # quiet_mode
OPENCODE_ANTIGRAVITY_DEBUG=1         # debug
OPENCODE_ANTIGRAVITY_LOG_DIR=/path   # log_dir
OPENCODE_ANTIGRAVITY_KEEP_THINKING=1 # keep_thinking

{
  "$schema": "https://raw.githubusercontent.com/NoeFabris/opencode-antigravity-auth/main/assets/antigravity.schema.json",
  "quiet_mode": false,
  "debug": false,
  "log_dir": "/custom/log/path",
  "auto_update": true,
  "keep_thinking": false,
  "session_recovery": true,
  "auto_resume": true,
  "resume_text": "continue",
  "empty_response_max_attempts": 4,
  "empty_response_retry_delay_ms": 2000,
  "tool_id_recovery": true,
  "claude_tool_hardening": true,
  "proactive_token_refresh": true,
  "proactive_refresh_buffer_seconds": 1800,
  "proactive_refresh_check_interval_seconds": 300,
  "max_rate_limit_wait_seconds": 300,
  "quota_fallback": false,
  "signature_cache": {
    "enabled": true,
    "memory_ttl_seconds": 3600,
    "disk_ttl_seconds": 172800,
    "write_interval_seconds": 60
  }
}

Troubleshoot

Multi account auth issues

If you encounter auth issue please try remove antigravity-account.json and auth again

Gemini model not found

Try add this line to in google field under provider "npm": "@ai-sdk/google"

Error during the session

If you encounter error during the session, try chat continue the recover session mechanism should be trigger and you can continue the session, if the error blocked the session please workaround by use command /undo to revert to the state before the error and try again it should work

Known Plugin Interactions

@tarquinen/opencode-dcp

DCP creates synthetic assistant messages that lack thinking blocks. Our plugin must be listed BEFORE DCP:

{
  "plugin": [
    "opencode-antigravity-auth@beta",
    "@tarquinen/opencode-dcp@latest",
  ]
}

oh-my-opencode

When using opencode-antigravity-auth, disable the built-in auth and override agent models in oh-my-opencode.json:

{
  "google_auth": false,
  "agents": {
    "frontend-ui-ux-engineer": { "model": "google/gemini-3-pro-high" },
    "document-writer": { "model": "google/gemini-3-flash" },
    "multimodal-looker": { "model": "google/gemini-3-flash" }
  }
}

When spawning parallel subagents, multiple processes may select the same account causing rate limit errors. Workaround: Add more accounts via opencode auth login.

Plugins You Don't Need

gemini-auth plugins - Not needed. This plugin handles all Google OAuth authentication.

If upgrading from v1.2.6 or earlier:

What Changed

v1.2.7+ uses explicit prefixes to distinguish quota sources:

| Model Type | New Name (Recommended) | Old Name (Still Works) | |------------|------------------------|------------------------| | Gemini 3 (Antigravity) | antigravity-gemini-3-pro-low | gemini-3-pro-low | | Gemini 3 (Antigravity) | antigravity-gemini-3-pro-high | gemini-3-pro-high | | Gemini 3 (Antigravity) | antigravity-gemini-3-flash | gemini-3-flash | | Gemini 3 (CLI) | gemini-3-pro-preview | N/A | | Claude | antigravity-claude-sonnet-4-5 | claude-sonnet-4-5 |

Action Required

Update your config to use antigravity- prefix:

- "gemini-3-pro-low": { ... }
+ "antigravity-gemini-3-pro-low": { ... }

Why update? Old names work now as a fallback, but this depends on Gemini CLI using -preview suffix. If Google removes -preview in the future, old names may route to the wrong quota. The antigravity- prefix is explicit and stable.

Step 1: Clear Old Tokens (Optional - do this if you have issues calling models)

rm -rf ~/.config/opencode/antigravity-account.json
opencode auth login

Step 2: Update opencode.json

Models now use antigravity- prefix for Antigravity quota. See Available Models.

Step 3: Create antigravity.json (Optional)

{
  "$schema": "https://raw.githubusercontent.com/NoeFabris/opencode-antigravity-auth/main/assets/antigravity.schema.json",
  "quiet_mode": false,
  "debug": false
}

The plugin includes regression tests for stability verification. Tests consume API quota.

# Sanity tests (7 tests, ~5 min)
npx tsx script/test-regression.ts --sanity

# Heavy tests (4 tests, ~30 min)
npx tsx script/test-regression.ts --heavy

# Concurrent tests (3 tests)
npx tsx script/test-regression.ts --category concurrency

# Run specific test
npx tsx script/test-regression.ts --test thinking-tool-use

# List tests without running
npx tsx script/test-regression.ts --dry-run

Debugging

OPENCODE_ANTIGRAVITY_DEBUG=1 opencode   # Basic logging
OPENCODE_ANTIGRAVITY_DEBUG=2 opencode   # Verbose (full request/response bodies)

Logs are written to ~/.config/opencode/antigravity-logs/.

Documentation

Architecture - Plugin internals and request flow
API Spec - Antigravity API reference

Intended Use

Personal / internal development only
Respect internal quotas and data handling policies
Not for production services or bypassing intended limits

Warning (Assumption of Risk)

By using this plugin, you acknowledge:

Terms of Service risk - This approach may violate ToS of AI model providers
Account risk - Providers may suspend or ban accounts
No guarantees - APIs may change without notice
Assumption of risk - You assume all legal, financial, and technical risks

Legal

Not affiliated with Google. This is an independent open-source project.
"Antigravity", "Gemini", "Google Cloud", and "Google" are trademarks of Google LLC.
Software is provided "as is", without warranty.

Credits

Built with help from:

opencode-gemini-auth - Gemini OAuth groundwork by @jenslys
CLIProxyAPI - Antigravity API reference

Support

If this plugin helps you, consider supporting its continued maintenance:

License

MIT