Add a YouTube playlist
Notebook Clipper adds every video in a YouTube playlist to a notebook in Gemini Notebook (formerly NotebookLM), one source per video, transcript included. Videos already in the notebook are skipped, so adding the same playlist to the same notebook again never creates duplicates. The playlist must be public or unlisted.
Add the playlist
There are three ways to add a playlist to Gemini Notebook.
Click Add to Gemini Notebook in the playlist header
The button sits next to Play all, Save and Share. The extension first fetches every video in the playlist; a notification shows the progress, and long playlists take a while. The Add to Notebook dialog opens when it is done.

Select a notebook
Choose a notebook in the Add to Notebook dialog, or click New notebook to create one. If every new video fits, they are added right away and the dialog closes.

Select the videos, if asked
If the playlist has more new videos than the notebook has room for, the dialog asks you to choose. Select the videos you want.

Click Add to notebook
The button is at the bottom of the dialog. If everything fitted at step 2, the videos are already in and there is nothing to click.