The lessons so far in this Part have been about Copilot reaching further: grounding automatically (4.1) and an agent you built (4.2). A Notebook is the one tool in this Part that deliberately does the opposite: it narrows what Copilot can see, on purpose.
What a Notebook actually is
Microsoft describes a Notebook as an intelligent, scoped workspace: you create one, add the Microsoft 365 files, Copilot pages, and other references relevant to a task, then ask questions and get answers grounded only in what you added. The basic shape, a persistent home for one piece of ongoing work, isn't far from a Claude Project. What's genuinely different is what "scoped" means in practice.
The real divergence: grounding turns off
You already know from lesson 4.1 that standard Copilot Chat grounds every prompt automatically against your mail, files, chats, and whatever connectors reach, whether you asked it to or not. A Notebook switches that off. Inside one, Copilot draws only on the references you explicitly added, not your broader OneDrive, not your inbox, not Teams chats, not the open web, even though all of those are normally fair game the moment you step outside the notebook.
A Claude Project doesn't work this way at all: it adds a curated knowledge base on top of Claude's existing behaviour, it doesn't remove anything. A Notebook actively restricts Copilot to less than it would normally see. That makes a Notebook the right tool for exactly the situations where you want a guarantee that nothing outside a specific set of documents influenced the answer, a due-diligence review, a compliance read-through, a contract comparison, where "it might have also glanced at something else in my mailbox" is actually a problem, not a convenience.
Picture the practical difference. Ask standard Copilot Chat "what does our vendor agreement say about termination," and grounding might pull in the actual contract, but it might also surface an old email thread where someone paraphrased the clause incorrectly, and you'd have no easy way to tell which shaped the answer. Ask the same question inside a notebook that contains only the signed contract, and there's exactly one place the answer could have come from.
What counts as a source
Sources can be Word, PowerPoint, Excel, or PDF files, Copilot pages, Loop components, OneNote pages and notebooks, and specific web URLs you add directly, which Copilot then grounds on just like any other reference. A notebook draws on up to 300 files to generate an answer; point it at a shared folder or site and Copilot considers everything you can access there and selects up to 300 of the most relevant. To guarantee one particular file actually gets used, add it to the notebook directly rather than relying on a shared location to surface it.
Getting started
Creating a notebook needs a SharePoint or OneDrive licence alongside your Copilot or Copilot Chat licence; Microsoft 365 Personal, Family, and Premium subscribers have access too. Once it exists, references can be swapped or updated as the work evolves, and changes take effect immediately, no rebuild required.
What you can generate that a plain chat can't
Beyond grounded answers to direct questions, a notebook can produce summaries and thematic analysis across everything you've added, draft emails, plans, and reports built from your selected material, and apply custom instructions that set the tone or format every answer should follow. One feature has no real Claude Project equivalent at all: audio overviews, a spoken summary of your notebook's material you can listen to instead of reading, currently available in eight languages for both input and output.
That last one is worth picturing concretely: load a notebook with the quarter's three biggest reports, ask for an audio overview, and get back something closer to a short briefing you can play on a commute than a document you have to sit down and read. It's a genuinely different way to consume the same material, not just another output format.
What it can't do yet
Image generation and charts, graphs, or other data visualisations aren't supported inside a notebook. And one limitation worth knowing before you lean on a notebook for anything you can't afford to lose: deleting a notebook, or a Copilot page inside one, is currently permanent. There's no recycle bin yet, though Microsoft has one in development for notebooks and expects one sooner for Copilot pages. Until then, treat deletion the way you'd treat deleting a file with no backup.
Where it earns its keep against a Project
Reach for a Notebook when the whole point is a hard boundary: you need an answer that's provably grounded in exactly these documents and nothing else, plus the option to generate a polished summary or even an audio briefing from them. Reach for a Claude Project instead when you want an ongoing body of work to carry context forward while Claude still behaves normally otherwise, brainstorming, iterating, drawing on its general knowledge alongside your files. Neither is strictly better: a Notebook trades flexibility for a guarantee, a Project keeps the flexibility and adds persistent memory on top of it.
Worth noting plainly rather than glossing over: Microsoft's own documentation says less about sharing a notebook with colleagues than Claude says about sharing a Project, where view-only versus full-edit roles on Team and Enterprise plans are spelled out clearly. If collaborating on the same ongoing workspace with a team is the main thing you need, that's one more point worth weighing before picking which tool fits the job.
Where this goes next
You can now manage the context Copilot builds automatically, package a repeatable job into an agent, and lock Copilot to exactly the material a piece of work actually needs. The next lesson, Researcher and Analyst, introduces Copilot's own specialist agents for when a question needs real depth. After that, Connectors closes out Part 4 by showing how outside systems join the mix.
Try it
Pick a real piece of work where you'd want a guaranteed answer from a fixed set of documents, a contract review, a policy comparison, a report built from three specific files. Create a notebook, add exactly those files and nothing else, and ask your real question. Then ask yourself: would you have trusted a plain Copilot Chat answer to the same question as much, knowing it might have quietly drawn on something else in your mailbox too?