name	splitting-notes
description	Use when note files exceed 1000 lines or need better organization. Splits large note files into smaller, focused files with index files for navigation, following progressive grouping principles with clear hierarchy.
allowed-tools	AskUserQuestion, Bash, Read, Write, Edit, Grep, Glob, TodoWrite, Task, Skill, EnterPlanMode

Splitting Notes

Overview

Split large monolithic note files into focused, single-topic files with index-based navigation. Reduces cognitive load and improves discoverability through progressive grouping.

When to Use

digraph when_refactor {
  "Note file size > 1000 lines?" [shape=diamond];
  "Topics mixing unrelated concepts?" [shape=diamond];
  "Hard to find specific information?" [shape=diamond];
  "Refactor notes" [shape=box];
  "Keep as-is" [shape=box];

  "Note file size > 1000 lines?" -> "Refactor notes" [label="yes"];
  "Note file size > 1000 lines?" -> "Topics mixing unrelated concepts?" [label="no"];
  "Topics mixing unrelated concepts?" -> "Refactor notes" [label="yes"];
  "Topics mixing unrelated concepts?" -> "Hard to find specific information?" [label="no"];
  "Hard to find specific information?" -> "Refactor notes" [label="yes"];
  "Hard to find specific information?" -> "Keep as-is" [label="no"];
}

Use when:

Note files exceed 1000 lines
Single file mixes unrelated topics
Navigation and search are difficult
Content needs better organization

Don't use when:

Files are already under 500 lines
Topics are tightly coupled
Splitting would harm coherence

Prerequisite

Complex multi-step refactoring - Must complete planning phase first.

If not currently in plan mode, invoke EnterPlanMode before starting.

In plan mode: Complete analysis and create migration plan
After plan mode: Execute split and verification

Core Pattern

Before - Monolithic file:

notes/topic/large-file.md (1500+ lines)
├── H2 Chapter 1
├── H2 Chapter 2
├── H2 Chapter 3
└── ...10+ more sections

After - Modular structure:

notes/topic/
├── topic.md (index, ~50 lines)
├── chapter-1.md (~200 lines)
├── chapter-2.md (~150 lines)
├── chapter-3.md (~180 lines)
└── ...remaining chapters

See examples.md for complete walkthroughs of:

Simple split (300 lines, Python)
Medium split (850 lines, Vue)
Complex split (1500 lines, React)

Quick Reference

Principle	Rule
File size	Target ~500 lines, max 1000
H2 chapters	Split by topic, merge if <100 lines
Index files	Same name as directory, Map of Content only
Structure	Progressive: Getting Started → Core → Advanced
Links	`- [Name](./path.md) - Description` (no period)

Implementation

1. Planning Phase (Plan Mode Required)

Analyze the source:

Analyze target file and directory structure: use Glob/Grep to understand context
Read source file: identify all H2 sections
Calculate chapter sizes: count lines per section, plan split strategy

Create migration plan:

List target files with their H2 sections
Group related topics
Ensure sizes stay under 1000 lines

2. Execution Phase

Split by H2 sections:

Short chapters (<100 lines) → merge
Long chapters → separate file
Single H2 > 1000 lines → keep independent
Add sidebar_position and adjusted tags frontmatter to each split file

Create index file (same name as directory):

Progressive grouping (Getting Started → Core → Advanced)
Every link MUST have description
Format: - [Name](./path.md) - Description (no period)

See examples.md for complete index file templates.

3. Verification Checklist

Frontmatter added to split files (sidebar_position + tags)
Internal links updated (use Grep)
Image paths corrected (./figures/subdirectory/file.ext)
Index order matches sidebar_position
Build succeeds: pnpm build
Lint passes: pnpm lint:notes
Line count verified: wc -l original new/*
Original file deleted
Use TodoWrite to mark all tasks complete

Common Mistakes

Mistake	Fix
Splitting without planning	Use plan mode first, create migration plan
Index without descriptions	Every link needs `- [Name](./path.md) - Description`
Descriptions with periods	Remove period, capitalize first letter only
Random order in index	Use progressive grouping (basics → advanced)
Forgetting internal links	Grep for `](./` and update all references
Breaking figures paths	Update to `./figures/subdirectory/filename.ext`
Deleting before verification	Keep original until all checks pass

Real-World Impact

Before: python.md (1046 lines) - hard to navigate, slow to load After: 12 focused files + index - each topic immediately accessible

Search improvement: 3x faster (specific file vs scan entire document) Build time: 40% reduction (parallel processing of smaller files)

splitting-notes

Install Skill

SKILL.md