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Closer to production quality Python notebooks with `marimo check`

31 pointsposted 8 days ago

by dmadisetti

(marimo.io)

14 Comments

wodenokoto

3 hours ago

I’m very interested in moving beyond Jupyter notebooks so I have my eye on marimo.

My understanding is it’s just python code with a bit of notebook hints and an idea that gives the notebook experience.

So I didn’t quite catch from the article why ruff and pylons aren’t enough.

Hi! Thanks for your interest. marimo is much more than that — unlike traditional notebooks, marimo is "reactive", meaning it models notebooks as dataflow graphs and keeps code an outputs in sync. Moreover, marimo notebooks are not "just notebooks". They can be seamlessly run as interactive web apps or as Python scripts.

Here is our original ShowHN post that explains what marimo is all about: https://news.ycombinator.com/item?id=38971966

Blog that goes deeper: https://marimo.io/blog/lessons-learned

daxfohl

2 hours ago

I was just thinking about something like this a couple hours ago.

Jeremy Howard (fast.ai, etc) posted a few weeks ago about his new AI class [1] and I was pumped. I went through the fast.ai course a couple years ago and had been wondering if another would ever come out, and the overview of this sounded really interesting. But the first thing the announcement went into was Jupyter Notebooks, and it kept on and on about them and I rolled my eyes. I remember they were my least favorite part of the fast.ai class. They've always felt awkward to me, being used to a code editor and all the functionality it provides, and I'm sure I'm not alone.

I'm sure Jupyter is great for fast iteration if that's what you do all day, but if you spend most of your life in a standard code editor, you really want something that starts from there and adds a bit of interactivity on top, rather than jumping to a completely different concept. I haven't tried marimo yet, but I might give it a shot for my next project.

[1] https://news.ycombinator.com/item?id=45455810

dmadisetti

8 days ago

marimo notebooks double as python Python programs, which means they can be lint-ed like any other code. `marimo check` catches notebook-specific issues (variable redefinition across cells, circular dependencies) with Rust-inspired (and uv; uv is amazing) error messages. It outputs JSON for AI agents to self-correct, integrates into CI pipelines, and includes `--fix` flags for automatic repairs. The team is already using it in their own CI and seeing Claude Code iterate on notebooks without human intervention.

sixo

2 hours ago

Unfortunately the code in Marimo notebooks implements cross-variable references as untyped function arguments, meaning that nothing passed between cells can be type-safe. This makes it very hard to use tooling directly on the Python representation of notebooks.

dmadisetti

2 hours ago

Arguments are typed if explicitly specified in definition, e.g.

    ```python
    @app.cell
    def my_cell():
        x : int = 1
        return (x,)

    @app.cell
    def consumer(x : int):
        y = x
        return
    ```

We've talked about building out implicit typing into our serialization- but that may be a larger can of worms.

aitchnyu

2 hours ago

IME Agents work fine on human readable error messages.

ZeroCool2u

2 hours ago

Any updates on the revamped VS Code extension? That's kind of a deal breaker for me.

dmadisetti

2 hours ago

Soft launched in pre-release, but a full version is coming!

loveparade

3 hours ago

I wish this didn't have AI in it. I've been looking for a Jupyter alternative that is pure python and can be modified from a regular text editor. Jupytext works okay, but I miss the advanced Jupyter features. But I really don't want to deal with yet another AI assistant, especially not a custom one when I'm already using Claude/etc from the CLI and I want those agents to help me edit the notebooks.

Take out all the AI stuff and I'd give it a try. I use AI coding agents as my daily driver, but I really don't need this AI enshittification in every tool/library I'm using.

daxfohl

2 hours ago

Reading the article, I don't think it has AI. They've just made the tools in a way that AI assistants can also use them, and so fix linting errors without anyone needing to fine-tune the LLM on the syntax.

That's actually pretty slick. I've been wondering how we could avoid blocking innovation in programming languages because of the death cycle of "no training data on language -> LLM can't learn language -> Assistant can't code language -> nobody uses language -> no training data on language".

dmadisetti

2 hours ago

> But I really don't want to deal with yet another AI assistant, especially not a custom one when I'm already using Claude/etc from the CLI and I want those agents to help me edit the notebooks.

So funny story- you can use exactly the same CLI tools in your notebook. Zed built out the ACP spec [1] which lets Claude Code go anywhere that implements it (as of Oct 2nd; emacs, vim, zed and marimo [2])

[1]: https://github.com/agentclientprotocol/agent-client-protocol

[2]: https://zed.dev/blog/acp-progress-report

3eb7988a1663

3 hours ago

I hate how much I lean into VSCode, but the Python interactive mode gets you a really good live coding environment. Instead of Jupyter cells, you have a regular .py file with chunks of code prefixed with a `# %%`. VSCode gives you a similar experience to a notebook, with the same controls (Run Above Cells, Restart and Run All, etc). So something like

  # %%
  import polars as pl

  # %%
  df = pl.DataFrame()
  df.shape

  # %%
  def foobar():
    return 1

Since it is a regular .py file all of your existing tooling will work with it. The one thing you lose vs a Jupyter notebook is saved output. I mostly use these .py files, but have a few .ipynb notebook files for when I want to commit the output from some important task.

akshayka

2 hours ago

You can not use the AI features, nothing is enabled by default (you have to bring your own keys)