feat: Add option to create notebook from file tree

[daizutabi]

📝 Summary

This pull request addresses issue #5220 by introducing a streamlined way to create new marimo notebooks directly from the file explorer. Previously, users could only create generic files or folders, making the process of starting a new notebook less intuitive.

Closes #5220

🔍 Description of Changes

1. Frontend Enhancements:

   • A dedicated "Add notebook" button, featuring the marimo icon, has been integrated into the file explorer's toolbar for quick access.
   • An equivalent "Create notebook" option is now available within the dropdown menu for directories, allowing for notebook creation within specific folders.

2. Backend Logic for Notebook Creation:

   • The RequestingTree.createFile method in the frontend now accepts an optional type parameter, which can be "notebook".
   • On the backend, marimo/_server/files/os_file_system.py has been updated to handle the new "notebook" file type. When a notebook is requested, it initializes the new file with the standard marimo notebook boilerplate by utilizing AppFileManager. This ensures newly created notebooks are immediately functional.

📋 Checklist

• I have read the contributor guidelines.
• For large changes, or changes that affect the public API: this change was discussed or approved through an issue, on Discord, or the community discussions (Please provide a link if applicable).
• Tests have been added for the changes made.
• Documentation has been updated where applicable, including docstrings for API changes.
• Pull request title is a good summary of the changes - it will be used in the release notes.

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Project	Deployment	Actions	Updated (UTC)
marimo-docs	Ready	Preview, Comment	Feb 23, 2026 4:45am

[Light2Dark]

code looks good otherwise :)

[Light2Dark]

Was trying out some designs, maybe this looks better?

          <span className="relative inline-flex">
            <img
              src={marimoIcon}
              className="w-4 h-4 shrink-0 filter grayscale"
              alt="Marimo"
            />
            <PlusIcon
              className="w-2 h-2 absolute -bottom-0.5 -right-1 bg-background text-muted-foreground rounded-full"
              strokeWidth={3}
            />
          </span>

[daizutabi]

Thanks for sharing your design idea. I've actually just finished implementing a similar approach. If you see any areas for improvement or modifications, please let me know or feel free to suggest them.

[Light2Dark]

nice, thanks!

[Yasin197]

looking forward to this quality of life improvement!