Grok Video Edit

Grok Video Edit is the node you reach for when you want to change what's happening inside a clip - "make it snow", "turn day into night", "have the car turn left" - without touching a frame or re-rendering from scratch. You hand it an existing video and a text description of the desired result, and xAI's Grok model re-renders the clip to match. It's one of ComfyUI's built-in partner nodes, so it's a cloud call: your clip gets uploaded to Comfy's API, proxied to Grok, and a new VIDEO comes back. Your GPU is a bystander.

The mental model matters here. This is editing by re-description, not by compositing. The prompt isn't a diff ("keep everything, only remove the sign") - it's a description of the video you want, and the model rebuilds toward it. Small, well-scoped changes land best; asking for a subtle tweak on a busy clip is where it gets sloppy, because the whole frame can drift. If you need surgical, pixel-exact edits, this isn't the tool - that's what local inpainting-style nodes are for.

The inputs

• video - the clip to edit. The hard limits are in the tooltip: max 8.7 seconds and 50MB. Anything longer or heavier gets rejected before you're billed, so pre-trim with a video tool first.
• prompt - the text description of the desired video. This is the whole game; be specific about what changes and what must stay the same.
• model - the Grok video model to use.
• seed - as with all these API nodes, it only decides whether the node re-runs. Results are nondeterministic regardless of seed, so don't expect reproducibility.

What comes out

A single VIDEO output with the edited clip. Wire it to a Save WEBM / save-video node or a preview; you can also chain it into Grok Video Extend if you want to keep the shot going afterward.

Gotchas

• Duration and size limits are the #1 rejection. People feed in a 20-second clip and wonder why it errors. Trim first - the node will tell you the limit.
• "Edit" is a full re-render. It costs like a fresh generation and takes about as long. Don't use it when you only need to trim or crop; that's free and instant locally.
• Seed doesn't give you a do-over. Because output is nondeterministic, changing the seed is just "run it again and hope" - which is actually the right way to fish for a better take on the same prompt.

If you're new to the partner-node family: this ships with ComfyUI core, needs a logged-in Comfy account (no vendor key to paste), and billing runs through your account credits per call. Read the error message when a run fails - Comfy validates before it charges, so a rejected request shouldn't hit your wallet.