source-lm
Bulk-add JSON exports, YouTube and links to NotebookLM
About source-lm
Source LM is a Chrome and Edge extension for people who need to load large batches of material into a NotebookLM or Gemini Notebook. It takes a JSON export such as a Telegram chat, a support-ticket dump or any file of records, and packs the records into Markdown files that stay under the per-source word cap without splitting a record across files.
It also adds YouTube videos, playlists and channels from buttons placed inside YouTube, pasted lists of links, Notion pages and selected text. Re-running an export uploads only new records, with progress read back from the notebook's own source names. Files are built in memory and pushed into the open notebook, so nothing is written to disk.
The extension has no backend and no account. Single sources are free, and bulk actions have a monthly allowance, with a one-time Pro licence for unlimited use. The code is published unminified under a noncommercial source-available licence.
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