penmentor
AI mentor that marks handwritten math with hints
EducationOpen sourceOpen source · verified#math#ai-mentor#linux
Listed by the ProductPerch team from Hacker News · not launched here yet
What is penmentor?
penmentor is a local tool that acts as a visual math mentor for students using a pen tablet. It integrates with Xournal++ to capture your handwritten work and sends it to AI models running on your machine. When you press a bound key, the system overlays colored marks directly onto your digital paper, circling mistakes, ticking correct steps, and underlining inherited errors. Instead of giving direct answers, it provides a ladder of hints to guide your thinking.
The tool supports whole-page context sharing, so the AI sees your complete workspace rather than a cropped screenshot. It can also generate interactive animations using the manim library to visualize complex concepts like Riemann sums. Users configure which AI agent to use, such as Claude Code, Codex, or Antigravity, and run the software entirely on their own subscriptions without sending data to third-party servers.
penmentor features
- Marks handwritten math directly on screen
- Provides hints instead of direct answers
- Generates interactive manim animations
- Shares full page context for accurate feedback
- Integrates with Claude, Codex, and Antigravity CLI agents
- Circles mistakes and ticks correct steps visually
Who uses penmentor and for what
- Students practicing calculus with a pen tablet
- Self-taught learners reviewing handwritten notes
- Tutors providing visual feedback on student work
- Developers using CLI tools to automate study workflows
penmentor FAQ
Is penmentor free?
Yes, it is released under an MIT license and runs locally. You need your own subscription for the AI models it connects to.
Does penmentor work on Mac?
The website does not say. It currently requires Linux on X11 with specific tools like rofi, slop, and xdotool.
What AI models does penmentor support?
It works with Claude, Gemini, and GPT through local CLI agents like Claude Code, Codex, and Antigravity. You select the model in settings.
Is penmentor open source?
Yes, the repository is public and licensed under the MIT license.
How does penmentor give feedback?
It circles the first real mistake, ticks correct lines, underlines inherited errors, and provides hints rather than direct answers.
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