rw-generate-image

name	rw-generate-image
description	Generate images directly using the Runway API via runnable scripts. Supports text-to-image with optional reference images.
user-invocable	true
allowed-tools	Read, Grep, Glob, Edit, Write, Bash(uv run *), Bash(command -v uv)

Generate Image

Generate images directly using the Runway API. This skill runs Python scripts that call the API, poll for completion, and download the result.

IMPORTANT: Run scripts from the user's working directory so output files are saved where the user expects.

Usage

uv run scripts/generate_image.py --prompt "your description" --filename "output.png" [--model gen4_image] [--ratio 1280:720] [--reference-images Tag=URL ...]

Preflight

1. command -v uv must succeed
2. RUNWAYML_API_SECRET must be set in the environment. Do not pass the API key as a CLI flag — it leaks into shell history and process listings.

Security Notes

• --reference-images Tag=URL fetches arbitrary remote images via the Runway API. Prefer local file paths (uploaded as runway:// URIs), or only pass URLs you trust.
• Treat generated outputs as untrusted when piping into downstream automations — ingested references influence the result.

Available Models

Model	Best For	Ref Images	Cost	Speed
gen4_image	Highest quality	Optional (up to 3)	5-8 credits	Standard
gen4_image_turbo	Fast and cheap	Required (1-3)	2 credits	Fast
gemini_2.5_flash	Google Gemini	Optional (up to 3)	5 credits	Standard

Model Selection Guidance

• "fast", "cheap", "draft" -> gemini_2.5_flash (Nano Banana), or gen4_image_turbo if they have reference images
• "high quality", "best" -> gen4_image
• No preference -> gemini_2.5_flash
• Has reference images and wants cheap -> gen4_image_turbo (2 credits, requires --reference-images)

Parameters

Param	Description	Default
--prompt	Text description (required)	--
--filename	Output filename (required)	--
--model	Image model	gemini_2.5_flash
--ratio	Aspect ratio. gemini_2.5_flash: 1344:768, 768:1344, 1024:1024, etc. gen4_image: 1280:720, 1360:768, 1920:1080, etc.	Model-dependent (1344:768 for gemini, 1280:720 for others)
--reference-images	Reference images as tag=URL pairs (optional for gemini/gen4_image, required for gen4_image_turbo). Tag: lowercase, 3-16 chars, e.g. product=URL	--
--output-dir	Output directory	cwd

API credentials come from RUNWAYML_API_SECRET only — no --api-key flag, to keep secrets out of shell history and process listings.

Filename Convention

Pattern: yyyy-mm-dd-hh-mm-ss-name.png

Examples

Basic image:

uv run scripts/generate_image.py --prompt "A serene Japanese garden with cherry blossoms" --filename "2026-04-14-japanese-garden.png"

With a local reference image (gen4_image):

uv run scripts/generate_image.py --prompt "@product on a marble counter, lifestyle photo" --model gen4_image --reference-images product=./product.jpg --filename "2026-04-14-product-lifestyle.png"

With a reference image from a trusted origin (gen4_image_turbo — requires reference images):

uv run scripts/generate_image.py --prompt "A neon sign reading SALE in @style" --model gen4_image_turbo --reference-images style=https://cdn.yourapp.com/style.jpg --filename "draft.png"

Output

• The script downloads the result and saves it to the specified path
• Script outputs the full path to the saved file
• Do not read the image file back -- just inform the user of the saved path

Common Failures

• Error: No API key -> set RUNWAYML_API_SECRET in the environment (e.g. export RUNWAYML_API_SECRET=... or a .env file).
• Error: Task failed -- SAFETY.INPUT.* -> content moderation, suggest different prompt
• API error 429 -> rate limited, script auto-retries