Runway API — Gen-4, Gen-4 Image, Gen-4 Aleph, Act-Two character performance, Veo 3/3.1 pass-through, Seedance 2, Eleven-Labs-backed TTS/STS/dubbing. Activate when the user configures any `runway-*` node or asks about Runway's API. Sourced from the official Stainless-generated Python SDK (github.com/runwayml/sdk-python) on 2026-04-17.
Installation
Install with Codex or Claude Copy this prompt, paste it into Codex, Claude, or another assistant, and let it review the skill page and install it for you.
Runway API — Gen-4, Gen-4 Image, Gen-4 Aleph, Act-Two character performance, Veo 3/3.1 pass-through, Seedance 2, Eleven-Labs-backed TTS/STS/dubbing. Activate when the user configures any `runway-*` node or asks about Runway's API. Sourced from the official Stainless-generated Python SDK (github.com/runwayml/sdk-python) on 2026-04-17.
Runway Skill
When to use
User configures any runway-* node (runway-video, runway-aleph, runway-image, runway-act-two, runway-tts, runway-sts, runway-dubbing)
User asks about Runway pricing, ratios, durations, voice presets, or dubbing target languages
Universal rules (all Runway endpoints)
Every task is async. Submit returns {"id": "<task_id>"}. Poll GET /v1/tasks/{id} until status is SUCCEEDED or FAILED. Our backend uses AsyncPollConfig with 2s interval, 300 poll cap.
Base URL:https://api.dev.runwayml.com/v1 (yes — dev.runwayml.com, the API gateway).
Input URIs must be HTTPS. Data URIs work for images (_resolve_image in handler converts local paths). No raw file uploads in the submit body — use POST /v1/uploads first if you need to host a local file.
camelCase over the wire. The SDK uses snake_case (prompt_text), but the HTTP API uses camelCase (promptText, videoUri, promptImage, referenceImages, contentModeration, bodyControl, expressionIntensity, publicFigureThreshold, outputCount, audioUri, targetLang, disableVoiceCloning, dropBackgroundAudio, numSpeakers, referenceVideos, removeBackgroundNoise, presetId). The Runway handler already sends camelCase — don't re-translate.
Content moderation knob:contentModeration.publicFigureThreshold — "auto" (default) or "low" (less strict on recognizable faces). Available on Gen-4.5, Gen-4 Turbo, Gen-3a Turbo, Gen-4 Image (Turbo + base), Gen-4 Aleph, Act-Two.
Cancel/delete:DELETE /v1/tasks/{id} cancels a running task or deletes a completed one.
Every non-audio endpoint returns a task with output: [{"url": "..."}] once SUCCEEDED. Video endpoints return one MP4 URL per output (outputCount default 1). Image endpoints return one or more image URLs. TTS/STS/dubbing return audio URLs.
Auth failure playbook
401: RUNWAY_API_KEY env var missing or invalid. The key must come from dev.runwayml.com dashboard.
403: API is in limited preview — some accounts lack access to specific models. Confirm the user's plan tier.
400 on a ratio: model-specific. See per-endpoint tables; Gen-4.5 accepts different ratios than Veo 3.1 etc.