marimo-pair

This skill gives you full access to a running marimo notebook. You can read cell code, create and edit cells, install packages, run cells, and inspect the reactive graph — all programmatically. The user sees results live in their browser while you work through bundled scripts or MCP.

marimo notebooks are a dataflow graph — cells are the fundamental unit of computation, connected by the variables they define and reference. When a cell runs, marimo automatically re-executes downstream cells. You have full access to the running notebook. • Cells are your main lever. Use them to break up work and choose how and when to bring the human into the loop. Not every cell needs rich output — sometimes the object itself is enough, sometimes a summary is better. Match the presentation to the intent. • Understand intent first. When clear, act. When ambiguous, clarify. • Follow existing signal. Check imports, pyproject.toml, existing cells, and dir(ctx) before reaching for external tools. • Stay focused. Build first, polish later — cell names, layout, and styling can wait.

Only servers started with --no-token register in the local server registry and are auto-discoverable — starting without a token makes discovery easier. If a server has a token, set the MARIMO_TOKEN environment variable before calling the execute script (avoids leaking the token in process listings). The right way to invoke marimo depends on context (project tooling, global install, sandbox mode). See finding-marimo.md for the full decision tree. Do NOT use --headless unless the user asks for it. Omitting it lets marimo auto-open the browser, which is the expected pairing experience. If the user explicitly requests headless, offer to open it with open http://localhost:<port>.

Code runs inside the running marimo kernel — execute-code.sh POSTs it over HTTP and never invokes a local Python. So errors here are not caused by the local Python version, missing venv, or uv vs pip — they're problems with the code being sent. Fix the code (use a heredoc for anything multiline; don't try to one-line compound statements with ;).