Antigravity + Gemini CLI OAuth Plugin for Opencode

{
  "$schema": "https://opencode.ai/config.json",
  "plugins": ["opencode-antigravity-auth@latest"]
}

opencode run --model=google/antigravity-gemini-3-flash#high "Hello"
opencode run --model=google/antigravity-claude-opus-4-6-thinking#max "Hello"

Existing antigravity-accounts.json accounts are reused. Revoked refresh tokens still require a fresh Google sign-in. See the V2 migration and verification guide for configuration examples, current Antigravity protocol changes, and the runtime regression test.

The package also supports the V1 object plugin entrypoint in OpenCode 1.18.29+. The instructions below use V1 configuration and command syntax.

Install the opencode-antigravity-auth plugin and add the Antigravity model definitions to ~/.config/opencode/opencode.json by following: https://raw.githubusercontent.com/NoeFabris/opencode-antigravity-auth/dev/README.md

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

opencode auth login

opencode run "Hello" --model=google/antigravity-claude-opus-4-6-thinking --variant=max

opencode run "Hello" --model=google/antigravity-claude-opus-4-6-thinking --variant=max

Models

Model Reference

Antigravity quota (default routing for Claude and Gemini):

| Model | Variants | Notes | |-------|----------|-------| | antigravity-gemini-3-pro | low, high | Gemini 3 Pro with thinking | | antigravity-gemini-3.1-pro | low, high | Gemini 3.1 Pro with thinking (rollout-dependent) | | antigravity-gemini-3-flash | minimal, low, medium, high | Gemini 3 Flash with thinking | | antigravity-claude-sonnet-4-6 | — | Claude Sonnet 4.6 | | antigravity-claude-opus-4-6-thinking | low, max | Claude Opus 4.6 with extended thinking |

Gemini CLI quota (separate from Antigravity; used when cli_first is true or as fallback):

| Model | Notes | |-------|-------| | gemini-2.5-flash | Gemini 2.5 Flash | | gemini-2.5-pro | Gemini 2.5 Pro | | gemini-3-flash-preview | Gemini 3 Flash (preview) | | gemini-3-pro-preview | Gemini 3 Pro (preview) | | gemini-3.1-pro-preview | Gemini 3.1 Pro (preview, rollout-dependent) | | gemini-3.1-pro-preview-customtools | Gemini 3.1 Pro Preview Custom Tools (preview, rollout-dependent) |

Routing Behavior:

- Antigravity-first (default): Gemini models use Antigravity quota across accounts.

- CLI-first (cli_first: true): Gemini models use Gemini CLI quota first.

- When a Gemini quota pool is exhausted, the plugin automatically falls back to the other pool.

- Claude and image models always use Antigravity.

Model names are automatically transformed for the target API (e.g., antigravity-gemini-3-flash → gemini-3-flash-preview for CLI).

Using variants:

opencode run "Hello" --model=google/antigravity-claude-opus-4-6-thinking --variant=max

For details on variant configuration and thinking levels, see docs/MODEL-VARIANTS.md.

{
  "$schema": "https://opencode.ai/config.json",
  "plugin": ["opencode-antigravity-auth@latest"],
  "provider": {
    "google": {
      "models": {
        "antigravity-gemini-3-pro": {
          "name": "Gemini 3 Pro (Antigravity)",
          "limit": { "context": 1048576, "output": 65535 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] },
          "variants": {
            "low": { "thinkingLevel": "low" },
            "high": { "thinkingLevel": "high" }
          }
        },
        "antigravity-gemini-3.1-pro": {
          "name": "Gemini 3.1 Pro (Antigravity)",
          "limit": { "context": 1048576, "output": 65535 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] },
          "variants": {
            "low": { "thinkingLevel": "low" },
            "high": { "thinkingLevel": "high" }
          }
        },
        "antigravity-gemini-3-flash": {
          "name": "Gemini 3 Flash (Antigravity)",
          "limit": { "context": 1048576, "output": 65536 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] },
          "variants": {
            "minimal": { "thinkingLevel": "minimal" },
            "low": { "thinkingLevel": "low" },
            "medium": { "thinkingLevel": "medium" },
            "high": { "thinkingLevel": "high" }
          }
        },
        "antigravity-claude-sonnet-4-6": {
          "name": "Claude Sonnet 4.6 (Antigravity)",
          "limit": { "context": 200000, "output": 64000 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        },
        "antigravity-claude-opus-4-6-thinking": {
          "name": "Claude Opus 4.6 Thinking (Antigravity)",
          "limit": { "context": 200000, "output": 64000 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] },
          "variants": {
            "low": { "thinkingConfig": { "thinkingBudget": 8192 } },
            "max": { "thinkingConfig": { "thinkingBudget": 32768 } }
          }
        },
        "gemini-2.5-flash": {
          "name": "Gemini 2.5 Flash (Gemini CLI)",
          "limit": { "context": 1048576, "output": 65536 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        },
        "gemini-2.5-pro": {
          "name": "Gemini 2.5 Pro (Gemini CLI)",
          "limit": { "context": 1048576, "output": 65536 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        },
        "gemini-3-flash-preview": {
          "name": "Gemini 3 Flash Preview (Gemini CLI)",
          "limit": { "context": 1048576, "output": 65536 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        },
        "gemini-3-pro-preview": {
          "name": "Gemini 3 Pro Preview (Gemini CLI)",
          "limit": { "context": 1048576, "output": 65535 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        },
        "gemini-3.1-pro-preview": {
          "name": "Gemini 3.1 Pro Preview (Gemini CLI)",
          "limit": { "context": 1048576, "output": 65535 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        },
        "gemini-3.1-pro-preview-customtools": {
          "name": "Gemini 3.1 Pro Preview Custom Tools (Gemini CLI)",
          "limit": { "context": 1048576, "output": 65535 },
          "modalities": { "input": ["text", "image", "pdf"], "output": ["text"] }
        }
      }
    }
  }
}

Multi-Account Setup

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

opencode auth login  # Run again to add more accounts

Account management options (via opencode auth login):

• Configure models — Auto-configure all plugin models in opencode.json
• Check quotas — View remaining API quota for each account
• Manage accounts — Enable/disable specific accounts for rotation

Troubleshooting

Quick Reset: Most issues can be resolved by deleting ~/.config/opencode/antigravity-accounts.json and running opencode auth login again.

Configuration Path (All Platforms)

OpenCode uses ~/.config/opencode/ on all platforms including Windows.

| File | Path | |------|------| | Main config | ~/.config/opencode/opencode.json | | Accounts | ~/.config/opencode/antigravity-accounts.json | | Plugin config | ~/.config/opencode/antigravity.json | | Debug logs | ~/.config/opencode/antigravity-logs/ |

Windows users: ~ resolves to your user home directory (e.g., C:\Users\YourName). Do NOT use %APPDATA%.

Custom path: Set OPENCODE_CONFIG_DIR environment variable to use a custom location.

Windows migration: If upgrading from plugin v1.3.x or earlier, the plugin will automatically find your existing config in %APPDATA%\opencode\ and use it. New installations use ~/.config/opencode/.

Multi-Account Auth Issues

If you encounter authentication issues with multiple accounts:

1. Delete the accounts file:

rm ~/.config/opencode/antigravity-accounts.json

1. Re-authenticate:

opencode auth login

403 Permission Denied (rising-fact-p41fc)

Error:

Permission 'cloudaicompanion.companions.generateChat' denied on resource 
'//cloudaicompanion.googleapis.com/projects/rising-fact-p41fc/locations/global'

Cause: Plugin falls back to a default project ID when no valid project is found. This works for Antigravity but fails for Gemini CLI models.

Solution:

1. Go to Google Cloud Console
2. Create or select a project
3. Enable the Gemini for Google Cloud API (cloudaicompanion.googleapis.com)
4. Add projectId to your accounts file:

{
     "accounts": [
       {
         "email": "[email protected]",
         "refreshToken": "...",
         "projectId": "your-project-id"
       }
     ]
   }

Note: Do this for each account in a multi-account setup.

Gemini Model Not Found

Add this to your google provider config:

{
  "provider": {
    "google": {
      "npm": "@ai-sdk/google",
      "models": { ... }
    }
  }
}

Gemini 3 Models 400 Error ("Unknown name 'parameters'")

Error:

Invalid JSON payload received. Unknown name "parameters" at 'request.tools[0]'

Causes:

• Tool schema incompatibility with Gemini's strict protobuf validation
• MCP servers with malformed schemas
• Plugin version regression

1. Update to latest beta:

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

1. Disable MCP servers one-by-one to find the problematic one

1. Add npm override:

{ "provider": { "google": { "npm": "@ai-sdk/google" } } }

MCP Servers Causing Errors

Some MCP servers have schemas incompatible with Antigravity's strict JSON format.

Common symptom:

Invalid function name must start with a letter or underscore

Sometimes it shows up as:

GenerateContentRequest.tools[0].function_declarations[12].name: Invalid function name must start with a letter or underscore

This usually means an MCP tool name starts with a number (for example, a 1mcp key like 1mcp_*). Rename the MCP key to start with a letter (e.g., gw) or disable that MCP entry for Antigravity models.

Diagnosis:

1. Disable all MCP servers in your config
2. Enable one-by-one until error reappears
3. Report the specific MCP in a GitHub issue

"All Accounts Rate-Limited" (But Quota Available)

Cause: Cascade bug in clearExpiredRateLimits() in hybrid mode (fixed in recent beta).

Solutions:

1. Update to latest beta version
2. If persists, delete accounts file and re-authenticate
3. Try switching account_selection_strategy to "sticky" in antigravity.json

Session Recovery

If you encounter errors during a session:

1. Type continue to trigger the recovery mechanism
2. If blocked, use /undo to revert to pre-error state
3. Retry the operation

Using with Oh-My-OpenCode

Important: Disable the built-in Google auth to prevent conflicts:

// ~/.config/opencode/oh-my-opencode.json
{
  "google_auth": false,
  "agents": {
    "frontend-ui-ux-engineer": { "model": "google/antigravity-gemini-3-pro" },
    "document-writer": { "model": "google/antigravity-gemini-3-flash" }
  }
}

Infinite .tmp Files Created

Cause: When account is rate-limited and plugin retries infinitely, it creates many temp files.

Workaround:

1. Stop OpenCode
2. Clean up: rm ~/.config/opencode/*.tmp
3. Add more accounts or wait for rate limit to expire

OAuth Callback Issues

# Find process using the port
lsof -i :51121

Kill if stale
kill -9 <PID>
Retry
opencode auth login

netstat -ano | findstr :51121
taskkill /PID <PID> /F
opencode auth login

ssh -L 51121:localhost:51121 user@remote

Configuration Key Typo: plugin not plugins

The correct key is plugin (singular):

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

Not "plugins" (will cause "Unrecognized key" error).

Migrating Accounts Between Machines

When copying antigravity-accounts.json to a new machine:

1. Ensure the plugin is installed: "plugin": ["opencode-antigravity-auth@beta"]
2. Copy ~/.config/opencode/antigravity-accounts.json
3. If you get "API key missing" error, the refresh token may be invalid — re-authenticate

Known Plugin Interactions

Plugin Compatibility

@tarquinen/opencode-dcp

DCP creates synthetic assistant messages that lack thinking blocks. List this plugin BEFORE DCP:

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

oh-my-opencode

Disable built-in auth and override agent models in oh-my-opencode.json:

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

Tip: When spawning parallel subagents, enable pid_offset_enabled: true in antigravity.json to distribute sessions across accounts.

Plugins you don't need

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

Configuration

Create ~/.config/opencode/antigravity.json for optional settings:

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

Most users don't need to configure anything — defaults work well.

Model Behavior

| Option | Default | What it does | |--------|---------|-------------- | keep_thinking | false | Preserve Claude's thinking across turns. Warning: enabling may degrade model stability. | | session_recovery | true | Auto-recover from tool errors | | cli_first | false | Route Gemini models to Gemini CLI first (Claude and image models stay on Antigravity). |

Account Rotation

| Your Setup | Recommended Config | |------------|-------------------| | 1 account | "account_selection_strategy": "sticky" | | 2-5 accounts | Default ("hybrid") works great | | 5+ accounts | "account_selection_strategy": "round-robin" | | Parallel agents | Add "pid_offset_enabled": true |

Quota Protection

| Option | Default | What it does | |--------|---------|--------------| | soft_quota_threshold_percent | 90 | Skip account when quota usage exceeds this percentage. Prevents Google from penalizing accounts that fully exhaust quota. Set to 100 to disable. | | quota_refresh_interval_minutes | 15 | Background quota refresh interval. After successful API requests, refreshes quota cache if older than this interval. Set to 0 to disable. | | soft_quota_cache_ttl_minutes | "auto" | How long quota cache is considered fresh. "auto" = max(2 × refresh interval, 10 minutes). Set a number (1-120) for fixed TTL. |

How it works: Quota cache is refreshed automatically after API requests (when older than quota_refresh_interval_minutes) and manually via "Check quotas" in opencode auth login. The threshold check uses soft_quota_cache_ttl_minutes to determine cache freshness - if cache is older, the account is considered "unknown" and allowed (fail-open). When ALL accounts exceed the threshold, the plugin waits for the earliest quota reset time (like rate limit behavior). If wait time exceeds max_rate_limit_wait_seconds, it errors immediately.

Rate Limit Scheduling

Control how the plugin handles rate limits:

| Option | Default | What it does | |--------|---------|--------------| | scheduling_mode | "cache_first" | "cache_first" = wait for same account (preserves prompt cache), "balance" = switch immediately, "performance_first" = round-robin | | max_cache_first_wait_seconds | 60 | Max seconds to wait in cache_first mode before switching accounts | | failure_ttl_seconds | 3600 | Reset failure count after this many seconds (prevents old failures from permanently penalizing accounts) |

When to use each mode:

• cache_first (default): Best for long conversations. Waits for the same account to recover, preserving your prompt cache.
• balance: Best for quick tasks. Switches accounts immediately when rate-limited for maximum availability.
• performance_first: Best for many short requests. Distributes load evenly across all accounts.

App Behavior

| Option | Default | What it does | |--------|---------|--------------| | quiet_mode | false | Hide toast notifications | | debug | false | Enable debug file logging (~/.config/opencode/antigravity-logs/) | | debug_tui | false | Show debug logs in the TUI log panel (independent from debug) | | auto_update | true | Auto-update plugin |

For all options, see docs/CONFIGURATION.md.

Environment variables:

OPENCODE_CONFIG_DIR=/path/to/config opencode  # Custom config directory
OPENCODE_ANTIGRAVITY_DEBUG=1 opencode         # Enable debug file logging
OPENCODE_ANTIGRAVITY_DEBUG=2 opencode         # Verbose debug file logging
OPENCODE_ANTIGRAVITY_DEBUG_TUI=1 opencode     # Enable TUI log panel debug output

Troubleshooting

See the full Troubleshooting Guide for solutions to common issues including:

• Auth problems and token refresh
• "Model not found" errors
• Session recovery
• Gemini CLI permission errors
• Safari OAuth issues
• Plugin compatibility
• Migration guides

Documentation

• Configuration — All configuration options
• Multi-Account — Load balancing, dual quota pools, account storage
• Model Variants — Thinking budgets and variant system
• Troubleshooting — Common issues and fixes
• Architecture — How the plugin works
• API Spec — Antigravity API reference

Support

If this plugin saves you time, consider supporting its development:

• opencode-gemini-auth by @jenslys
• CLIProxyAPI

License

MIT License. See LICENSE for details.