21st Video

Create the video with the user's coding agent and the 21st video tools. Keep the real editor open so the user can see changes and edit the same project by hand. Use the available tool input schemas as the source of truth for fields, operation names, limits, and supported formats.

Start from the product

Read the project's README, relevant screens/components, brand assets, and release notes. Use real product copy and assets. Establish one message, an appropriate aspect ratio, and a short scene sequence from the user's request. Keep claims grounded in the product. Respect project instructions and any restriction on browser or computer use. Reuse the user's running app; start a server only when authorized.