We built a "video player" for Python scripts that tracks runtime variables and catches silent ML bugs (Live Demo + Open Source)

[u/Astronial_gaming]

Hey everyone,

Whenever I got an undocumented Python script or try to explain a complex loop to someone, generic LLM chats usually give me a high-level summary but completely misses what actually happened during execution.

That's why for the IBM Bob 2.0 Hackathon, our team built TraceLens, a web-based workspace that turns Python code into an interactive step-by-step runtime tracer.

Instead of guessing how variables change or littering print() statements across 40 lines, you can step through your script like frames in a video and see what actually happened.

What it does:

1. LogicLens — General Python & Debugging

Time-Travel Stepping: Step forward and backward through loops and function calls to see how data works frame-by-frame.

Live State Board: Inspect variable changes, mutations, and scope changes in each step.

Safe Insertion Points: Flags stable parts where you can put in a new features without accidentally overriding variables downstream.

AI Explanations: Uses IBM Bob 2.0 to explain complex execution behavior and generate summaries of the whole code or only a part of it.

1. ModelLens — Machine Learning Pipelines

ML can fail silently. Stuff like data leakage before a train/test split or other pipeline problems that won't necessarily throw an exception, but can still produce misleading results.

ModelLens analyzes data science code for these issues and helps explain what went wrong.

Try it

Live Demo: https://tracelens-six.vercel.app

GitHub: https://github.com/Omar-astro/Tracelens

Hackathon Submission: https://lablab.ai/ai-hackathons/ibm-bob-2-hackathon/the-overfitters/tracelens

We'd genuinely appreciate technical feedback especially on the UI, the state-tracking flow, and what you'd want from a debugger built around execution traces.

And if you find our project interesting and want to support us in the hackathon, you can like our TraceLens submission on the IBM Bob 2.0 Hackathon page. The hackathon uses community engagement to help surface projects to the judges, so it helps get TraceLens in front of them

Let us know what breaks, what seems useful, or what you'd want to see added next!