j-cli — Jupyter CLI for LLM Agents

Overview

j-cli is a CLI tool that lets you operate Jupyter Lab servers. Use it to execute code in kernels, manage sessions, and write outputs back to notebooks. Always use --json (-j) flag when you need to parse the output programmatically.

One-time Claude Code hook install

Run this once per project to prevent Claude from falling back to jupyter nbconvert --execute (or papermill / runipy) instead of j-cli:

j-cli setup claude --local    # writes .claude/settings.local.json (gitignored, this machine only)
# or:
j-cli setup claude --project  # writes .claude/settings.json       (committed, team-shared)
# or:
j-cli setup claude --user     # writes ~/.claude/settings.json     (global, all projects)

The command is idempotent — re-running updates the hook in place without duplicating it.