I've tried it out a bit - it does look solid and it has a good team behind it.

It's a subset of Python though (much more so than MicroPython), which is fine for LLMs since they can easily work around any limitations but does mean you can't use a lot of existing Python code with it.

I'm also a little bit nervous about the safety. It's a fresh implementation in Rust, which means plenty of possibilities for edge case security bugs. The thing I like about WebAssembly is that there's a robust, well tested sandbox already - better for defense in depth.

I certainly wouldn't bet against Monty though! It may well prove itself to be a great solution for this.

That one looks pretty good - it's been around since 2016, I'm surprise I haven't encountered it before.

It's not quite right for what I'm after because you can't just "pip install" it on multiple platforms.

I'm using judge0 for a Leetcode-clone I'm working on. Never thought of using it in the context of LLMs, though.

Yeah I'm very loose with my prompting now - I can usually tell from the reasoning traces if it correctly interpreted any typos.

If it looks like it didn't I hit "stop" and then edit and resubmit my prompt.

I've had lots of fun with WASM Python in the browser - a few of my experiments with that are:

- https://lite.datasette.io - my Datasette app in a browser

- https://simonw.github.io/research/pyodide-asgi-browser/datas... is a new, improved version of that using Service Workers that's still a little experimental - notes here: https://simonwillison.net/2026/May/30/pyodide-asgi-browser/

- https://tools.simonwillison.net/micropython runs a MicroPython playground in the browser via WebAssembly

Running arbitrary untrusted code safely is pretty easy nowadays, so long as the code is written in Javascript and you want to run it in a browser. It's only a little harder if the code is written in another language but targets WASM and browser APIs, or if you want to run your WASM inside of NodeJS, and there's even good support for running Python in a browser or Node.

Once you get away from running in a JS environment or away from code that's written with the intention of running in a WASM sandbox, if you don't want to have to modify the code for your environment then you're going to start having problems. This looks like a good step for anyone wanting to run arbitrary Python outside of a browser environment.

For me it is a tool I avail to an LLM so that it can provide correct answers to a certain category of questions, instead of hallucinating nonsense.

The idea is to expose it as a tool to your LLM agent so it can run calculations on its own initiative.