jupyter-live-kernel✓ Pass

SKILL.md Content

---
name: jupyter-live-kernel
description: "Iterative Python via live Jupyter kernel (hamelnb)."
version: 1.0.0
author: Hermes Agent
license: MIT
platforms: [linux, macos, windows]
metadata:
  hermes:
    tags: [jupyter, notebook, repl, data-science, exploration, iterative]
    category: data-science
---

# Jupyter Live Kernel (hamelnb)

Gives you a **stateful Python REPL** via a live Jupyter kernel. Variables persist
across executions. Use this instead of `execute_code` when you need to build up
state incrementally, explore APIs, inspect DataFrames, or iterate on complex code.

## When to Use This vs Other Tools

| Tool | Use When |
|------|----------|
| **This skill** | Iterative exploration, state across steps, data science, ML, "let me try this and check" |
| `execute_code` | One-shot scripts needing hermes tool access (web_search, file ops). Stateless. |
| `terminal` | Shell commands, builds, installs, git, process management |

**Rule of thumb:** If you'd want a Jupyter notebook for the task, use this skill.

## Prerequisites

1. **uv** must be installed (check: `which uv`)
2. **JupyterLab** must be installed: `uv tool install jupyterlab`
3. A Jupyter server must be running (see Setup below)

## Setup

The hamelnb script location:
```
SCRIPT="$HOME/.agent-skills/hamelnb/skills/jupyter-live-kernel/scripts/jupyter_live_kernel.py"
```

If not cloned yet:
```
git clone https://github.com/hamelsmu/hamelnb.git ~/.agent-skills/hamelnb
```

### Starting JupyterLab

Check if a server is already running:
```
uv run "$SCRIPT" servers
```

If no servers found, start one:
```
jupyter-lab --no-browser --port=8888 --notebook-dir=$HOME/notebooks \
  --IdentityProvider.token='' --ServerApp.password='' > /tmp/jupyter.log 2>&1 &
sleep 3
```

Note: Token/password disabled for local agent access. The server runs headless.

### Creating a Notebook for REPL Use

If you just need a REPL (no existing notebook), create a minimal notebook file:
```
mkdir -p ~/notebooks
```
Write a minimal .ipynb JSON file with one empty code cell, then start a kernel
session via the Jupyter REST API:
```
curl -s -X POST http://127.0.0.1:8888/api/sessions \
  -H "Content-Type: application/json" \
  -d '{"path":"scratch.ipynb","type":"notebook","name":"scratch.ipynb","kernel":{"name":"python3"}}'
```

## Core Workflow

All commands return structured JSON. Always use `--compact` to save tokens.

### 1. Discover servers and notebooks

```
uv run "$SCRIPT" servers --compact
uv run "$SCRIPT" notebooks --compact
```

### 2. Execute code (primary operation)

```
uv run "$SCRIPT" execute --path <notebook.ipynb> --code '<python code>' --compact
```

State persists across execute calls. Variables, imports, objects all survive.

Multi-line code works with $'...' quoting:
```
uv run "$SCRIPT" execute --path scratch.ipynb --code $'import os\nfiles = os.listdir(".")\nprint(f"Found {len(files)} files")' --compact
```

### 3. Inspect live variables

```
uv run "$SCRIPT" variables --path <notebook.ipynb> list --compact
uv run "$SCRIPT" variables --path <notebook.ipynb> preview --name <varname> --compact
```

### 4. Edit notebook cells

```
# View current cells
uv run "$SCRIPT" contents --path <notebook.ipynb> --compact

# Insert a new cell
uv run "$SCRIPT" edit --path <notebook.ipynb> insert \
  --at-index <N> --cell-type code --source '<code>' --compact

# Replace cell source (use cell-id from contents output)
uv run "$SCRIPT" edit --path <notebook.ipynb> replace-source \
  --cell-id <id> --source '<new code>' --compact

# Delete a cell
uv run "$SCRIPT" edit --path <notebook.ipynb> delete --cell-id <id> --compact
```

### 5. Verification (restart + run all)

Only use when the user asks for a clean verification or you need to confirm
the notebook runs top-to-bottom:

```
uv run "$SCRIPT" restart-run-all --path <notebook.ipynb> --save-outputs --compact
```

## Practical Tips from Experience

1. **First execution after server start may timeout** — the kernel needs a moment
   to initialize. If you get a timeout, just retry.

2. **The kernel Python is JupyterLab's Python** — packages must be installed in
   that environment. If you need additional packages, install them into the
   JupyterLab tool environment first.

3. **--compact flag saves significant tokens** — always use it. JSON output can
   be very verbose without it.

4. **For pure REPL use**, create a scratch.ipynb and don't bother with cell editing.
   Just use `execute` repeatedly.

5. **Argument order matters** — subcommand flags like `--path` go BEFORE the
   sub-subcommand. E.g.: `variables --path nb.ipynb list` not `variables list --path nb.ipynb`.

6. **If a session doesn't exist yet**, you need to start one via the REST API
   (see Setup section). The tool can't execute without a live kernel session.

7. **Errors are returned as JSON** with traceback — read the `ename` and `evalue`
   fields to understand what went wrong.

8. **Occasional websocket timeouts** — some operations may timeout on first try,
   especially after a kernel restart. Retry once before escalating.

## Timeout Defaults

The script has a 30-second default timeout per execution. For long-running
operations, pass `--timeout 120`. Use generous timeouts (60+) for initial
setup or heavy computation.

License

Declared license: MIT

MIT License

Copyright (c) 2025 Hermes Agent

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

View the license in the source repository — the version published there is authoritative.