ChatGPT Projects, Claude Projects or NotebookLM: which should hold your documents?

All three tools let you upload a set of documents once and then work with them over many conversations, instead of pasting the same files into every new chat. That shared idea hides real differences. Each was designed around a different job, and the right home for your documents depends on which job you do most.

A quick note on terms. A project in ChatGPT or Claude is a workspace that groups chats, uploaded files and standing instructions. A notebook in Google's NotebookLM is a similar container, but everything in it revolves around the sources you add, and answers are tied back to them. Both approaches rely on the model reading your files when it answers, so the quality of what you upload matters as much as the tool.

What each one is built for

ChatGPT Projects started as folders for related chats, files and custom instructions. An update announced on June 12, 2025 made them more of a workspace: you can now run deep research inside a project, which combines your files and instructions with results from the public web, use voice mode, upload files from the mobile app, and, on Plus and Pro, let memory draw on earlier chats in the same project. Tools such as Canvas, a side-by-side editor, also work there.

Claude Projects hold a curated set of "project knowledge" plus the chats about it. Anthropic gives each project a 200,000-token context window, which it compares to a 500-page book, so a large amount of material can be in view at once. Custom instructions set the tone or role, for example "answer as our grant writer."

NotebookLM is built around grounded answers. When you ask a question, it replies from your uploaded sources and shows citations with the relevant quotes, so you can check each claim. It can also produce an Audio Overview, a spoken discussion of your sources by two AI hosts.

A worked comparison on one set of documents

Imagine a community theater with an illustrative set of nine files: the bylaws, three years of board minutes, a grant report, a volunteer handbook, a season budget spreadsheet and two press releases. Here is how the same three tasks might go in each tool.

The pattern is clear enough to act on. When accuracy against the documents matters most, NotebookLM's citations make checking fast. When you are producing a long piece of writing from a big body of material, Claude's project knowledge is the natural fit. When the work is ongoing and mixes your files with fresh information from the web, ChatGPT Projects bring the most tools together.

Practical limits to keep in mind

All three read what you give them and nothing else from your files, so outdated or contradictory documents produce outdated or contradictory answers. Remove old drafts before uploading. Spreadsheets and scanned PDFs can be harder for a model to read than clean text, so test one before you rely on it. Usage limits differ by plan and change often, so check each service's current help pages for the number of files and their size. Finally, sharing works differently in each: Team users of Claude can share conversation snapshots into a project's activity feed, and ChatGPT lets you share a single conversation from a project by link without exposing the project's other files or instructions.

How do you keep sensitive files out?

Start before uploading. Ask of each file: would I be comfortable if a colleague outside my organization read it? Personnel records, medical details, donor or client lists, contracts under confidentiality, and anything with account numbers or passwords fail that test. Leave them out, or make a cleaned copy with names and identifiers removed. Often a summary you write yourself gives the AI all it needs.

Then check how each service treats your data. Anthropic says material shared in Projects is not used to train its models without your explicit consent. Google says personal data in NotebookLM is not used to train NotebookLM. OpenAI says projects follow your existing ChatGPT privacy settings, so if you have turned off the setting that allows your content to improve its models, project content is not used for training. Look at that setting before you upload anything.

Finally, match the plan to the material. Work documents that belong to an employer or clients should go only into the business or education versions your organization has approved, which come with their own data agreements. When in doubt, ask the person responsible for data in your organization first; deleting a file later does not undo the fact that it was shared.