Generate timestamped B-roll image prompts

Part of the AI character reel system. An Airtable button on a script record calls the webhook. The workflow reads the script, B-roll style prompt, theme angle, setting and chunk length in seconds, and asks the AI model set on the theme to split the script into chunks of about that length.

For each chunk the model writes one B-roll image prompt with no faces and no on-screen text. A Code step turns the reply into rows, and each row is saved as a B-roll record with the script excerpt, start and end timecodes, the image prompt and a chapter label, ready for the B-roll image step. The script's status moves to AI Complete and token usage is logged.