Better-Gemini

ComfyUI Better Gemini

ComfyUI V3 nodes for generating images and text with Google Gemini and xAI Grok.

This repo provides two nodes:

• Better Gemini for Gemini image and text generation
• Better Grok for Grok image generation, image editing, and text chat

Install

1. Clone into your ComfyUI custom_nodes directory:
   • cd /path/to/ComfyUI/custom_nodes
   • git clone https://github.com/<you>/ComfyUI-Better-Gemini.git
2. Install Python deps with uv:
   • uv sync
   • uv pip install --python /path/to/ComfyUI/python/bin/python -e ./ComfyUI-Better-Gemini
3. Set API keys as needed:
   • export GOOGLE_API_KEY="..." or export GEMINI_API_KEY="..."
   • export XAI_API_KEY="..."
4. Restart ComfyUI.

Nodes

Better Gemini

• Inputs: prompt, model, response_modalities (IMAGE, IMAGE+TEXT, TEXT), optional prompt images, aspect ratio, resolution or width+height, temperature, top_p, top_k, max tokens, thinking controls, seed, optional output caching
• Outputs: IMAGE, STRING
• Use it when you want one node that can handle both Gemini image models and Gemini text-only models

Better Grok

• Inputs: prompt, model, response_modalities (IMAGE, IMAGE+TEXT, TEXT), reasoning effort (none, low, medium, high), optional prompt images, aspect ratio, resolution, n, optional output caching
• Outputs: IMAGE, STRING
• Use it when you want Grok image generation, image editing, or a text-only Grok call from the same node

Output Behavior

• In TEXT mode, the usable model output is returned through STRING.
• In TEXT mode, the IMAGE output is a minimal blank 1x1 tensor so ComfyUI graphs can stay connected without allocating a large placeholder.
• In IMAGE+TEXT mode, image generation still runs and any returned notes or revised prompt text are placed in STRING.
• If Gemini or Grok returns no images when image output was requested, the node emits a blank placeholder image and includes a note in STRING.
• If cache_outputs is enabled, model outputs are stored under .cache/ and identical future requests reuse the cached IMAGE/STRING outputs without calling Gemini or Grok.

Model Dropdowns

• Gemini model options are populated via client.models.list() without action-based filtering, so both image-capable and text-only Gemini models can appear in the same dropdown.
• Grok model options merge xAI /v1/image-generation-models and /v1/language-models, so image and language models can appear in the same dropdown.
• If an API key is unavailable or model listing fails, each node falls back to bundled default model names.

Bundled fallback models:

• Gemini: gemini-3.1-flash-lite-image, gemini-3-flash-preview, gemini-3.1-flash-image-preview, gemini-3.1-flash-lite-preview, gemini-3-pro-image-preview, gemini-3.1-pro-preview, imagen-4.0-generate-001, imagen-4.0-ultra-generate-001
• Grok: grok-imagine-image, grok-imagine-image-pro, grok-imagine-image-quality, grok-latest, grok-4, grok-4-fast-non-reasoning, grok-3-mini, grok-code-fast-1

Recommended text-only examples:

• Gemini: gemini-3-flash-preview, gemini-3.1-flash-lite-preview, gemini-3.1-pro-preview
• Grok: grok-latest, grok-4, grok-4-fast-non-reasoning, grok-3-mini, grok-code-fast-1

Example Workflow

Implementation Notes

• The Gemini node imports google-genai lazily so ComfyUI can still boot even if dependencies are not installed yet; execution raises a clear error until installed.
• This extension uses ComfyUI's V3 extension loader via comfy_entrypoint.
• Gemini requires seed to fit in an int32; larger ComfyUI seeds are deterministically folded via seed % 2**31.
• When response_modalities=TEXT, Gemini requests omit image-specific config.
• Grok image generation is wired against xAI's documented image endpoints and requests response_format="b64_json", so the node can return image tensors directly instead of downloading temporary URLs.
• The Grok HTTP client sends an explicit application User-Agent because api.x.ai can reject the default Python-urllib signature with Cloudflare 1010.
• Grok image edits use xAI's JSON-based /v1/images/edits API and send ComfyUI IMAGE inputs as PNG data URIs. Multiple prompt images are supported for edit and merge workflows.
• Grok TEXT mode uses xAI's /v1/responses endpoint with configurable reasoning effort and store=false, since node calls are not reused as xAI chat sessions. If prompt images are attached, the node sends them as response image inputs and returns the model's text through STRING.
• Output caching uses the SHA-256 checksum of canonical Gemini or Grok request data as the manifest filename, with string and image payloads stored as separate content-addressed files.
• resolution and aspect_ratio are best-effort, model-dependent settings. The node logs a warning if the returned size does not match the request.

Dev

• Sync dev environment: uv sync --dev
• Run unit tests: uv run python -m unittest discover -s tests -p 'test_*.py' -v