notebook.split_header_cells

notebook.split_header_cells is a skill for Claude Code, Codex from causify-ai/helpers. It costs 15 tokens per session (408 once invoked), scanned A, original, Apache-2.0.

A notebook-formatting guide that puts each heading and its accompanying text in a separate Jupyter notebook cell. Jupyter notebooks use cells to organize code and written explanations.

In plain words
What is it for?
Splitting Markdown header cells, removing extra blank lines, and synchronizing the paired Python file without changing code cells.
Why use it?
It makes the notebook structure easier to scan and prevents several levels of headings from being mixed in one cell.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/causify-ai/helpers/notebook.split_header_cells
Any agent
npx skills add causify-ai/helpers --skill notebook.split_header_cells
Clone the repo
git clone --depth 1 https://github.com/causify-ai/helpers

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for notebook.split_header_cells

README.md
[![agentmods](https://agentmods.dev/badge/skills/causify-ai/helpers/notebook.split_header_cells.svg)](https://agentmods.dev/skills/causify-ai/helpers/notebook.split_header_cells)
Your own site
<a href="https://agentmods.dev/skills/causify-ai/helpers/notebook.split_header_cells"><img src="https://agentmods.dev/badge/skills/causify-ai/helpers/notebook.split_header_cells.svg" alt="Measured on agentmods" height="20"></a>
Per session 15 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 408 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00015 $0.00408
Opus 5 $0.00008 $0.00204
Sonnet 5 $0.00003 $0.00082
Haiku 4.5 $0.00002 $0.00041

Measured 2d ago against content hash 43c2bd4f8247, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade A, and why

notebook.split_header_cells scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.claude/skills/notebook.split_header_cells/SKILL.md · 63 lines

What it actually says

Goal

  • Format the markdown cells to match

Workflow

Split Markdown Cells

  • Make sure that each markdown cell in a Jupyter notebook contains at most one header and some text, but not more than one header
    • Bad (there are 3 headers in the same cell: one H1, one H2, one H3)
      # %% [markdown]
      # Part 3: Composition Examples
      
      ## Example 1: Minimal End-to-End Workflow
      
      Rain → Sprinkler → Grass Wet
      
      ### Mental Model
      
    • Good (each header is in a different cell)
      # %% [markdown]
      # Part 3: Composition Examples
      
      # %% [markdown]
      ## Example 1: Minimal End-to-End Workflow
      
      Rain → Sprinkler → Grass Wet
      
      # %% [markdown]
      ### Mental Model
      
    • Do not change the content of the markdown text besides splitting cells into multiple ones

Remove Empty Lines

  • Remove empty lines at the beginning or end of a markdown cell
    • Bad (there are two headers in the same cell, one H1 and one H2)
      
      # %% [markdown]
      # Part 3: Composition Examples
      
      
      
    • Good (each header is in a different cell)
      # %% [markdown]
      # Part 3: Composition Examples
      

Important

  • Do not change or remove any Python code cell
  • At the end of the transformation, run jupytext --sync to update the Python paired notebook, following the conventions in # Setup and Initialization## Utilities vs. Notebook Responsibilities in .claude/skills/notebook.rules.md
Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 63 lines · 15 tokens per session scan A 43c2bd4f8247

Subscribe to this mod's changes

notebook.split_header_cells is a skill published in the GitHub repository causify-ai/helpers (145 stars, last pushed today), licensed Apache-2.0. It adds 15 tokens to every session and 408 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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