Source LM

Source LM is a Chrome extension that gets material into a NotebookLM or Gemini Notebook notebook in bulk, without downloading anything to disk. Three inputs: (1) a JSON dataset (e.g. a Telegram chat export) is split into Markdown files word-budgeted under NotebookLM's 500,000-word per-source cap, records never split across files, and re-running uploads only the new records; (2) YouTube — "Add to notebook" buttons injected into YouTube's own UI add the current video, a playlist, or a channel's latest N videos as one source per video, with optional top comment threads; (3) links and pages — a pasted URL list, the current page, or a right-click on selected text. Extras: batch source deletion, duplicate-source finder, broken-source listing with manual replace, source filter box. No backend: the extension talks only to the notebook page's own origin. No account, no telemetry. Source-available under the PolyForm Noncommercial License 1.0.0, shipped unminified. Free plan: 5 bulk actions per month, single sources always free. Pro: $29 one-time, no subscription.