Google’s NotebookLM Adds 'Deep Research' Agent and New File Support, Becoming a True Intelligence Powerhouse

Google has just unveiled its most significant update yet for NotebookLM, the viral AI note-taking tool that took the tech world by storm earlier this year. Released today, November 13, 2025, the update fundamentally changes the platform’s capabilities by introducing "Deep Research"—an autonomous agent that can scour the web to build reports—alongside highly requested support for Google Sheets and Microsoft Word. This move effectively breaks down the tool's previous "walled garden," where answers were strictly limited to user-uploaded documents, transforming it into a proactive research partner.

The standout feature is the new Deep Research agent, which offers a massive leap over the existing "Fast Research" quick-scan option. When given a topic, this agent doesn't just search; it autonomously executes a sophisticated workflow: plan, read, compare, cite, and present. It acts like a dedicated researcher running in the background, navigating hundreds of websites to synthesize findings into a comprehensive report. Crucially, this generated report is saved directly into the user's notebook as a new source. This approach leverages "retrieval-augmented" workflows, a core principle Google is emphasizing to mitigate AI hallucinations by ensuring every claim is anchored to a verifiable reference.

Beyond the web capabilities, the update addresses the community’s biggest feature requests regarding file compatibility. NotebookLM now supports Google Sheets and Microsoft Word (.docx) files, a game-changer for data-heavy projects. Users can now upload a spreadsheet of financial quarters or survey results and ask the AI to cross-reference that structured data with text documents. The update also refines the daily workflow by allowing users to add Google Drive files, including PDFs, via a simple URL copy-paste or file picker, finally bypassing the tedious requirement of downloading and re-uploading documents.

This evolution signals a long journey for a tool that started as "Project Tailwind" at Google I/O in 2023. Running on the Gemini AI engine, NotebookLM has rapidly grown from a niche study aid into a robust intelligence instrument for academic and corporate use. These new features are rolling out immediately and will reach all users over the coming week, positioning the platform to compete directly with other autonomous research agents while maintaining Google’s signature focus on sourcing and data privacy.