opencode-gemini-imagegen

OpenCode plugin for Gemini image generation via Antigravity Manager.

Prerequisites

• Antigravity Manager running locally at http://127.0.0.1:8045
• The manager must have gemini-3-pro-image model available

Installation

Add to your opencode.json:

{
  "plugin": [
    "opencode-gemini-imagegen"
  ]
}

Then install dependencies:

cd ~/.config/opencode && bun install

Usage

Once installed, any model can call the gemini_image tool:

User: Generate an image of a futuristic city
Assistant: [calls gemini_image(prompt="futuristic city with neon lights and flying cars", size="1920x1080", quality="hd")]

Result:
## Image Generated Successfully

**File**: `./generated-images/futuristic-city-2026-02-03T15-30-42.jpg`
**Format**: image/jpeg
**Dimensions**: 1920x1080
**Quality**: hd

Configuration

Configure via environment variables:

| Variable | Default | Description | |----------|---------|-------------| | OPENCODE_IMAGE_BASE_URL | http://127.0.0.1:8045/v1 | Antigravity Manager URL | | OPENCODE_IMAGE_API_KEY | (from ANTIGRAVITY_MANAGER_API_KEY) | API key | | OPENCODE_IMAGE_MODEL | gemini-3-pro-image | Model for image generation | | OPENCODE_IMAGE_TIMEOUT_MS | 120000 | Request timeout (ms) | | OPENCODE_IMAGE_OUTPUT_DIR | ./generated-images | Output directory |

Tool Arguments

| Argument | Type | Default | Description | |----------|------|---------|-------------| | prompt | string | (required) | Image description | | size | string | 1024x1024 | Dimensions in WxH format (256-4096) | | quality | enum | hd | standard, hd, or medium | | filename | string | (auto) | Custom filename (without extension) |

Features

• Auto-detects image format (JPEG/PNG) from response
• Path traversal protection for filenames
• File collision handling with automatic suffix
• Memory protection for large responses
• Detailed error messages with actionable hints

Security Notes

• Generated images are saved locally only
• Filenames are sanitized to prevent path traversal
• Prompts may be rejected by content filters

License

MIT