skill

nano-banana-pro-openrouter

Generate or edit images via OpenRouter with the Gemini 3 Pro Image model. Use for prompt-only image generation, image edits, and multi-image compositing; supports 1K/2K/4K output.

github/awesome-copilot/skills/nano-banana-pro-openrouterofficiallistedunreviewednot running here yet

Use skill

Set up

Skills are installed by placing their folder where your agent loads skills.

Part of the collection github/awesome-copilot.

npx skills add github/awesome-copilot --skill nano-banana-pro-openrouter

Or by hand: Copy the folder skills/nano-banana-pro-openrouter from github.com/github/awesome-copilot into ~/.claude/skills/nano-banana-pro-openrouter/ (Claude Code) or your agent's skills folder. Check the collection's own README for other agents.

README

synced Oct 14, 2026

Nano Banana Pro OpenRouter

Overview

Generate or edit images with OpenRouter using the google/gemini-3-pro-image-preview model. Support prompt-only generation, single-image edits, and multi-image composition.

Prompt-only generation

uv run {baseDir}/scripts/generate_image.py \
  --prompt "A cinematic sunset over snow-capped mountains" \
  --filename sunset.png

Edit a single image

uv run {baseDir}/scripts/generate_image.py \
  --prompt "Replace the sky with a dramatic aurora" \
  --input-image input.jpg \
  --filename aurora.png

Compose multiple images

uv run {baseDir}/scripts/generate_image.py \
  --prompt "Combine the subjects into a single studio portrait" \
  --input-image face1.jpg \
  --input-image face2.jpg \
  --filename composite.png

Resolution

Use --resolution with 1K, 2K, or 4K.
Default is 1K if not specified.

System prompt customization

The skill reads an optional system prompt from assets/SYSTEM_TEMPLATE. This allows you to customize the image generation behavior without modifying code.

Behavior and constraints

Accept up to 3 input images via repeated --input-image.
--filename accepts relative paths (saves to current directory) or absolute paths.
If multiple images are returned, append -1, -2, etc. to the filename.
Print MEDIA: <path> for each saved image. Do not read images back into the response.

Troubleshooting

If the script exits non-zero, check stderr against these common blockers:

Symptom	Resolution
`OPENROUTER_API_KEY is not set`	Ask the user to set it. PowerShell: `$env:OPENROUTER_API_KEY = "sk-or-..."` / bash: `export OPENROUTER_API_KEY="sk-or-..."`
`uv: command not found` or not recognized	macOS/Linux: curl -LsSf https://astral.sh/uv/install.sh \| sh. Windows: powershell -ExecutionPolicy ByPass -c "irm https://astral.sh/uv/install.ps1 \| iex". Then restart the terminal.
`AuthenticationError` / HTTP 401	Key is invalid or has no credits. Verify at https://openrouter.ai/settings/keys.

For transient errors (HTTP 429, network timeouts), retry once after 30 seconds. Do not retry the same error more than twice — surface the issue to the user instead.