Nano Banana Image Generation (MCP)
Generate and edit images directly via the Nano Banana MCP server tools. No Gemini CLI dependency.
Upstream reference: https://github.com/gemini-cli-extensions/nanobanana
When to Use This Skill
ALWAYS use this skill when the user:
- Asks for any image, graphic, illustration, or visual
- Wants a thumbnail, featured image, or banner
- Requests icons, diagrams, or patterns
- Asks to edit, modify, or restore a photo
- Uses words like: generate, create, make, draw, design, visualize
Do NOT attempt to generate images through any other method.
Health Check
Before first use, verify prerequisites:
- Node.js >= 18 — required to run the MCP server
- API key set —
GEMINI_API_KEYorNANOBANANA_API_KEYenvironment variable - MCP server available — the nanobanana MCP tools should appear in your tool list
If MCP tools are not available, the plugin may need reinstalling. See references/troubleshooting.md.
Tool Selection
| User Request | MCP Tool |
|--------------|----------|
| "generate an image of..." | generate_image |
| "create an app icon" | generate_icon |
| "draw a flowchart of..." | generate_diagram |
| "fix this old photo" | restore_image |
| "edit this image" | edit_image |
| "create a repeating texture" | generate_pattern |
| "make a comic strip" | generate_story |
Quick Usage
Call the MCP tools directly with structured parameters:
Generate Images (default: 3 images)
Tool: generate_image
Parameters:
prompt: "a sunset over mountains, photorealistic"
outputCount: 3
Edit Existing Image
Tool: edit_image
Parameters:
prompt: "change the background to a beach scene"
file: "/absolute/path/to/image.jpg"
Generate App Icons
Tool: generate_icon
Parameters:
prompt: "coffee cup logo"
sizes: [64, 128, 256, 512]
type: "app-icon"
style: "modern"
corners: "rounded"
Generate Diagram
Tool: generate_diagram
Parameters:
prompt: "microservices architecture for e-commerce platform"
type: "architecture"
style: "professional"
complexity: "detailed"
For full parameter reference for all 7 tools, see references/commands.md.
Defaults
- File paths: Always resolve file paths to absolute paths before passing to any MCP tool. The MCP server runs in a different working directory, so relative paths will fail.
- outputCount: For
generate_image, always use 3 unless user specifies otherwise. Other tools have their own count semantics (e.g.,generate_iconusessizes,generate_storyusessteps). - Model:
gemini-3.1-flash-image-preview(override viaNANOBANANA_MODELenv var) - Output: Images saved to
./nanobanana-output/in current directory
Presenting Results
After generation completes:
- List contents of
./nanobanana-output/to find generated files - Present the most recent image(s) to the user using the Read tool
- Offer to regenerate with variations if needed
Refinements and Iterations
When the user asks for changes:
- "Try again" / "Give me options": Call
generate_imageagain withoutputCount: 3 - "Make it more [adjective]": Adjust prompt and regenerate
- "Edit this one": Call
edit_imagewith the file path and edit instructions - "Different style": Add style to the
stylesarray parameter
Prompt Tips
- Be specific: Include style, mood, colors, composition details
- Add "no text": If you don't want text rendered in the image
- Reference styles: "editorial photography", "flat illustration", "3D render", "watercolor"
- Specify aspect ratio: Include "wide 16:9" or "square" in the prompt description
For image quality guidelines (style compliance, text accuracy, story consistency), see references/generation-guidelines.md.
For error troubleshooting, see references/troubleshooting.md.