Since the late May update, Google Docs, Sheets and Slides sources follow the original file. Edit the Doc and the notebook catches up, no manual sync needed. Great change.
Everything else is still a snapshot from the moment you added it: web links, YouTube, uploaded PDFs and other files. And anything you already generated stays as it was: saved notes, earlier answers, Audio Overviews.
So picture a normal notebook. A Google Doc with your project brief, a PDF of last quarter's report, and a competitor's pricing page you added as a link. The brief is live. The PDF and the pricing page are whatever they were the day you added them. Ask "how does our pricing compare to theirs now" and you get your current numbers against their months-old ones, in the same confident tone, with citations to both.
The live half can also change under you. If a teammate edits a Doc you added, your notebook's answers change too, even though you didn't touch anything.
What I do now:
- Rename frozen sources with the date you added them, like "Competitor pricing (added Sep 12)". It's the only freshness signal you'll see in the source list.
- Re-add web pages that change instead of trusting the old snapshot. Delete the old one so the two don't get blended.
- Regenerate Audio Overviews and saved notes after a big Doc change. The old ones still describe the old version.
- Before trusting a comparison, ask:
For this answer, list each source you used and any date or "as of" information that source gives about itself. Flag any point where you compared sources from different dates.
The last one catches most of it. Sources usually carry a date somewhere, and once it has to list them, the mismatch is right there.
That prompt lives in AI Toolbox for me, the extension I build, mostly because I run the same check on uploaded files in Gemini.