Enable Claude Code to see cell outputs in Marimo VSCode extension?

[cyniphile]

CC can see outputs via MCP if I used the vanilla marimo server + browser UI, but doesn't seem to work with the VSCode extension?

I can use claude code + vscode + marimo by running a marimo server in the background, so claude points to that sever while the VSCode notebook points to its own extension server, but of course this doubles resource use.

[manzt]

Thanks for starting this discussion! Improving agent integration (in VS Code and beyond) is a goal for us this year.

We're actively thinking about how to make the marimo + agent experience better. Curious if you've tried Claude Code with Jupyter in VS Code? It seems to have similar challenges there - any progress they make we could likely build on.

[cyniphile]

So far I only use marimo, as jupyter json diffs are too much of a mess to look at. Plus I've used marimo enough that I really don't want to give up the other benefits (mostly UI, e.g. the interactive df tables).

So far I've still had ok success using agents with marimo via two workarounds:

1. they "copy/paste" cell(s) code into their internal shell and run the code there
2. periodically export notebooks to html so agents can see output

Both suffer from having to re-run expensive cells instead of re-using existing variables/state already in memory.

I don't know much about VSCode internals or extensions, but somehow exposing this (see image) via MCP would be a nice start and vaguely seems doable.

[cyniphile]

A little wary of PRing slop, so I'll just share I've been using this (nearly 100% vibe-coded) fork and it works well: https://github.com/cyniphile/marimo-lsp/tree/feature/mcp-server

Saw you're working on marimo-team/marimo-lsp#378 already anyway, so maybe not necessary.