Nano Banana Setup

I'll help you configure Nano Banana for image and diagram generation.

Requirements

Nano Banana requires:

1. OpenRouter API Key - For accessing AI models (Gemini 3 Pro Image, FLUX, etc.)
2. Python 3.8+ - Uses stdlib only, no external dependencies required!

Step 1: Check Current Configuration

Let me check if you already have the required configuration:

# Check for OPENROUTER_API_KEY
if [ -n "$OPENROUTER_API_KEY" ]; then
    echo "✅ OPENROUTER_API_KEY is set in environment"
else
    echo "❌ OPENROUTER_API_KEY not found in environment"
fi

# Check for .env file
if [ -f ".env" ] && grep -q "OPENROUTER_API_KEY" .env; then
    echo "✅ OPENROUTER_API_KEY found in .env file"
fi

Step 2: Get Your OpenRouter API Key

If you don't have an OpenRouter API key:

1. Go to https://openrouter.ai/keys
2. Sign in or create an account
3. Click "Create Key"
4. Copy your API key (starts with sk-or-v1-...)
5. Add credits to your account

Step 3: Configure API Key

Choose ONE of these methods:

Option A: Environment Variable (Recommended)

Add to your shell profile (~/.zshrc or ~/.bashrc):

export OPENROUTER_API_KEY='sk-or-v1-your-key-here'

Then reload:

source ~/.zshrc  # or source ~/.bashrc

Option B: Project .env File

Create a .env file in your project root:

echo "OPENROUTER_API_KEY=sk-or-v1-your-key-here" > .env

Important: Add .env to your .gitignore:

echo ".env" >> .gitignore

Option C: Per-Command (For Testing)

Pass the key directly:

python generate_diagram.py "My diagram" -o diagram.png --api-key sk-or-v1-your-key-here

Step 4: Verify Installation

No dependency installation required! Nano Banana uses Python stdlib only.

Test that everything works:

# Test diagram generation
python skills/diagram/scripts/generate_diagram.py "Simple flowchart with start, process, and end boxes" -o test_diagram.png --doc-type presentation

# Test image generation
python skills/image/scripts/generate_image.py "A simple blue square" -o test_image.png

If successful, you'll see:

✅ Image saved to: test_diagram.png

Configuration Summary

After setup, your configuration should look like:

Component	Status
OPENROUTER_API_KEY	✅ Set (env or .env)
Python 3.8+	✅ Installed
External dependencies	✅ None required!

Optional: .env File Support

If you want to use .env files, install python-dotenv:

pip install python-dotenv
# or
uv pip install python-dotenv

This is optional - you can also just use exported environment variables.

Troubleshooting

"OPENROUTER_API_KEY not found"

• Ensure the environment variable is set: echo $OPENROUTER_API_KEY
• Or ensure .env file exists with the key
• Restart your terminal after adding to shell profile

"Permission denied" on scripts

chmod +x skills/*/scripts/*.py

API Errors

• Check your API key is correct
• Ensure you have credits in your OpenRouter account
• Check https://openrouter.ai/activity for usage and errors

Next Steps

You're all set! Try these commands:

# Generate an architecture diagram
python skills/diagram/scripts/generate_diagram.py "Microservices architecture with 3 services and a database" -o architecture.png --doc-type architecture

# Generate a creative image
python skills/image/scripts/generate_image.py "A cozy coffee shop interior, warm lighting" -o coffee_shop.png

# Edit an existing image
python skills/image/scripts/generate_image.py "Add rain to the window" --input coffee_shop.png -o rainy_coffee_shop.png

See the skill documentation for more examples:

• skills/diagram/SKILL.md - Technical diagram generation
• skills/image/SKILL.md - Image generation and editing
• skills/mermaid/SKILL.md - Text-based diagrams