nano-banana

name	nano-banana
description	Generate or edit images with OpenRouter using the google/gemini-3.1-flash-image-preview model. Use when the user asks for image generation, wants a new visual from a text prompt, or wants modifications to an existing screenshot or image and expects an image file back.
allowed-tools	Bash(node agent/skills/nano-banana/generate-image.js:*)

Nano Banana Image Generation

Use this skill when the user wants an image back, either from a fresh prompt or from editing an existing image.

Model

• Provider: OpenRouter
• Model: google/gemini-3.1-flash-image-preview
• Friendly name: Nano Banana

Supported workflows

1. Text-to-image: user provides a prompt, you generate an image.
2. Image edit: user provides an image or screenshot plus instructions, you generate a modified image.

Before you run

• Make sure the prompt is explicit enough to produce the desired image.
• If editing an image, first save or locate the input image path in the workspace.
• The script writes generated files to .context/generated-images/ by default.

Usage

Generate a new image

node agent/skills/nano-banana/generate-image.js \
  --prompt "A clean product hero shot of a matte black coffee grinder on a soft beige background, studio lighting" \
  --output .context/generated-images/coffee-grinder.png

Edit an existing image

node agent/skills/nano-banana/generate-image.js \
  --prompt "Keep the layout the same, but change the CTA button to green, replace the headline with 'Ship faster', and make the page look more premium" \
  --input-image path/to/screenshot.png \
  --output .context/generated-images/edited-screenshot.png

Response handling

• The script prints JSON with an output field containing the saved image path.
• After running it, tell the user the output file path.
• If the model returns no image, inspect the JSON warning and summarize the failure clearly.

Notes

• Prefer PNG outputs unless the user asks for another format.
• Preserve existing composition when the user asks for modifications to a screenshot.
• If the user’s request is ambiguous, clarify what should change and what must remain untouched.