Describe the Bug
I used Claude 4 Sonnet this morning to create a Jupyter Notebook and everything was working as expected: the LLM could see my notebook, edit it, etc. when coming back from lunch this afternoon nothing works anymore. The agent just tells me that the reading / editing tools are not working and tries to grep / sed everything from the shell, making an atrocious mess (not-mentioning the awful lot of tokens it uses by doing so).
I’m on a pro plan and we basically use notebooks everyday with the other scientists of my R&D company. Notebook support is crucial. And it is inconsistent, that’s what kills me with Cursor, it works like a charm one day, and all hell breaks lose the day after.
It’s been months since the “Jupyter Notebook Support” has been officially announced and it’s still completely broken. Please fix this.
Steps to Reproduce
Ask the LLM to edit an existing Jupyter Notebook and observe answers like:
Let me add the necessary imports and PPG plotting functionality. I'll need to add matplotlib and scipy imports, and create the PPG plotting code:
⚠ The string to replace was not found in file
Let me try a different approach. Since the file reading seems to have issues,
Operating System
MacOS
Current Cursor Version (Menu → About Cursor → Copy)
Version: 1.3.9 (Universal)
VSCode Version: 1.99.3
Commit: 54c27320fab08c9f5dd5873f07fca101f7a3e070
Date: 2025-08-01T20:27:38.378Z
Electron: 34.5.1
Chromium: 132.0.6834.210
Node.js: 20.19.0
V8: 13.2.152.41-electron.0
OS: Darwin arm64 24.5.0
Does this stop you from using Cursor
Yes - Cursor is unusable
