Project Instructions Development

Manages the complete lifecycle of project instructions: creating initial documentation, syncing with codebase patterns, and organizing modular rules.

When to Use This Skill

Use when:

• "Create CLAUDE.md for this project"
• "Initialize CLAUDE.md" or "generate CLAUDE.md"
• "Sync CLAUDE.md with my code"
• "Update documentation from codebase"
• "Extract patterns from code"
• "Create .claude/rules/ structure"
• "Split large CLAUDE.md"
• "Manage modular documentation"

What This Skill Does

Provides 4 main operations:

• ✅ Initialize: Create new CLAUDE.md with opinionated baseline standards
• ✅ Sync: Analyze codebase and update documentation with detected patterns
• ✅ Organize: Create or manage .claude/rules/ modular structure
• ✅ Split: Break large CLAUDE.md into focused rule files

Note: .claude/rules/ only works in project directories, not in global ~/.claude/

CRITICAL RULES

Language

• CLAUDE.md MUST be 100% in English (industry standard)
• Never mix languages in documentation
• Code, comments, and docs all in English

No Dynamic Data

• NEVER include: line counts, file counts, commit statistics, dates, timestamps
• NEVER write: "Analyzed X files", "Y lines of code", "Created on..."
• Only include: stable patterns, timeless structures, architectural principles

User Confirmation

• ALWAYS ask questions to understand context and preferences
• ALWAYS show preview before writing any files
• ALWAYS get explicit confirmation before creating/modifying files

Instructions

Step 0: Check Global Configuration (CRITICAL)

Before creating any project-level documentation, ALWAYS read the user's global CLAUDE.md:

# Check if global CLAUDE.md exists
~/.claude/CLAUDE.md

If it exists:

• Read and analyze what rules are already defined globally
• DO NOT duplicate global rules in project CLAUDE.md
• Only add project-specific patterns that differ from or extend global rules
• Mention to user: "I found your global CLAUDE.md - I'll only add project-specific rules"

If it doesn't exist:

• Proceed normally with project documentation

Step 1: Determine Operation and Complexity

Use AskUserQuestion tool with THREE questions:

{
  "questions": [
    {
      "question": "What do you need help with?",
      "header": "Operation",
      "multiSelect": false,
      "options": [
        {
          "label": "Create new CLAUDE.md",
          "description": "Start from scratch with opinionated baseline"
        },
        {
          "label": "Sync CLAUDE.md with existing code",
          "description": "Analyze codebase to detect patterns and update docs"
        },
        {
          "label": "Split large CLAUDE.md into rules/",
          "description": "Break CLAUDE.md (>500 lines) into focused files"
        }
      ]
    },
    {
      "question": "What complexity level?",
      "header": "Structure",
      "multiSelect": false,
      "options": [
        {
          "label": "Simple (just CLAUDE.md)",
          "description": "Single file, good for small/medium projects"
        },
        {
          "label": "Modular (CLAUDE.md + .claude/rules/)",
          "description": "Multiple files with path patterns, for large projects"
        }
      ]
    },
    {
      "question": "Should this be shared with your team or kept local?",
      "header": "Sharing",
      "multiSelect": false,
      "options": [
        {
          "label": "Shared (CLAUDE.md)",
          "description": "Committed to git, shared across team and sessions"
        },
        {
          "label": "Local only (CLAUDE.local.md)",
          "description": "Git-ignored, personal workspace rules only"
        }
      ]
    }
  ]
}

Route to workflow:

• Create new + Simple + Shared → Initialize Workflow (Step 2) - CLAUDE.md
• Create new + Simple + Local → Initialize Workflow (Step 2) - CLAUDE.local.md + add to .gitignore
• Create new + Modular + Shared → Initialize Workflow (Step 2) + Organize Workflow (Step 4) - CLAUDE.md
• Create new + Modular + Local → Initialize Workflow (Step 2) + Organize Workflow (Step 4) - CLAUDE.local.md + add to .gitignore
• Sync + Simple + Shared → Sync Workflow (Step 3) - update CLAUDE.md
• Sync + Simple + Local → Sync Workflow (Step 3) - update CLAUDE.local.md
• Sync + Modular → Sync Workflow (Step 3) + Organize Workflow (Step 4)
• Split → Split Workflow (Step 5)

---

Step 2: Initialize Workflow (Create New CLAUDE.md)

Create opinionated baseline CLAUDE.md for new projects.

Process:

1. Determine filename (from Step 1 answer):

   • Shared → CLAUDE.md
   • Local only → CLAUDE.local.md

2. Detect project type

   • Check if it's a code project (package.json, requirements.txt, go.mod, etc.)
   • Or non-code (docs, notes, research, etc.)
   • Ask user if unclear

3. Think through design:

   • Minimum viable CLAUDE.md?
   • Similar projects/patterns?
   • Architectural trade-offs?
   • Common pitfalls in this stack?

4. Show preview with:

   • Structure outline
   • Key sections
   • Estimated line count
   • Architecture reasoning
   • Filename that will be created

5. Generate and write (after confirmation):

   • Single file: ~150-250 lines
   • Modular: ~100-150 lines with references to rules/
   • Use determined filename from step 1

6. If local only (CLAUDE.local.md):

   • Add CLAUDE.local.md to .gitignore
   • Create .gitignore if it doesn't exist
   • Inform user it's git-ignored

7. Inform user with next steps

See references/initialize-workflow.md for complete details

---

Step 3: Sync Workflow (Analyze Code and Update Docs)

Analyze codebase to extract patterns and update documentation.

Process:

1. Detect current setup:

   • Check if CLAUDE.md exists
   • Check if .claude/rules/ exists
   • Determine mode: CREATE, UPDATE Single, UPDATE Modular

2. Analyze codebase (use Task tool with Explore agent):

   • Main source directory
   • Tech stack
   • Folder organization
   • Test patterns

3. Extract patterns:

   • Naming conventions (files, functions, variables)
   • Architectural pattern (FSD, Feature-First, etc.)
   • Import patterns
   • Testing conventions
   • Component/API patterns

4. Think through findings:

   • Stable (>80%) vs emerging patterns
   • What to document vs leave implicit
   • Single file or modular approach

5. Show findings to user:

   • Detected patterns
   • Mismatches with documented patterns
   • Recommendations

6. Ask approach (AskUserQuestion):

   • Update CLAUDE.md (single file)
   • Create .claude/rules/ (modular)
   • Show both options

7. Generate updates and write (after confirmation)

8. Inform user with summary of changes

See references/sync-workflow.md for complete details

---

Step 4: Organize Workflow (Create .claude/rules/ Structure)

Set up modular documentation with focused rule files.

Process:

1. Detect stack (same as initialize)

2. Ask which rules to create (AskUserQuestion):

   • coding-standards.md (recommended)
   • architecture.md (recommended)
   • testing.md
   • api.md

3. Think through design:

   • What in each file vs CLAUDE.md
   • Path patterns for each file
   • Keep each file <200 lines

4. Show preview:

   • File structure
   • Estimated line counts
   • Path patterns
   • CLAUDE.md updates

5. Create files (after confirmation):

   • Create .claude/rules/ directory
   • Create each rule file with YAML frontmatter
   • Update CLAUDE.md to reference rules

6. Inform user with structure overview

See references/organize-and-split-workflows.md for templates and details

---

Step 5: Split Workflow (Break Large CLAUDE.md)

Break CLAUDE.md (>500 lines) into focused modular files.

Process:

1. Read and analyze CLAUDE.md:

   • Identify sections
   • Core vs detailed content
   • Line counts per section

2. Think through split strategy:

   • What stays in CLAUDE.md (core standards)
   • What moves to rules/ (detailed guidelines)
   • Organize by topic
   • Path patterns

3. Show split preview:

   • Current vs after structure
   • What moves where
   • Line count reduction

4. Execute split (after confirmation):

   • Create .claude/rules/
   • Create rule files with moved content
   • Update CLAUDE.md (remove moved, add references)

5. Inform user with results

See references/organize-and-split-workflows.md for complete details

---

Architecture Pattern Selection

Quick reference:

Stack	Recommended Pattern
React/Vue SPA	Feature-Sliced Design (FSD)
Next.js	FSD or Feature-First
Express/Fastify	Feature-First
NestJS	Feature-First
Django/Flask	MVC
Rails	MVC
Spring Boot	Package by Feature
Go API	Package by Feature

See references/architecture-patterns.md for complete guide

Path Pattern Examples

# Coding standards for TypeScript
---
paths: src/**/*.{ts,tsx}
---

# Testing conventions
---
paths: **/*.{test,spec}.*
---

# API-specific rules
---
paths: src/{api,routes}/**/*
---

Related Settings Configuration

respectGitignore

Control whether @-mention file picker respects .gitignore:

{
  "respectGitignore": true
}

Add to .claude/settings.json (project-specific) or ~/.claude/settings.json (global).

Use when: You want file suggestions to exclude gitignored files

fileSuggestion

Customize @ file search commands:

{
  "fileSuggestion": {
    "command": "rg --files",
    "timeout": 5000
  }
}

Use when:

• You want faster file search than default
• You need custom filtering logic
• You have specific tooling (e.g., fd, find with custom flags)

These settings affect how documentation discovery and file reference tools work.

Best Practices

1. ✅ Ask questions first - Understand user needs
2. ✅ Show previews - Confirm before writing
3. ✅ English only - 100% English content
4. ✅ No dynamic data - Only stable patterns
5. ✅ Opinionated defaults - But let user choose
6. ✅ Explain choices - Why this architecture?
7. ✅ Keep concise - CLAUDE.md 150-250 lines, rules <200 lines
8. ✅ Think step-by-step - Analyze before generating
9. ✅ Progressive disclosure - Core in CLAUDE.md, details in rules/

Anti-Patterns

• ❌ Generating without asking questions
• ❌ Writing files without preview/confirmation
• ❌ Including line counts, file counts, dates, statistics
• ❌ Mixed languages (English + other)
• ❌ "Analyzed X files" or dynamic statements
• ❌ Timestamps or "last updated"
• ❌ Overly long files (>500 lines CLAUDE.md, >200 lines rules)
• ❌ Not explaining architectural choices
• ❌ Duplicating content between CLAUDE.md and rules/

Additional Resources

Reference Files

Complete workflows and detailed guides:

• references/initialize-workflow.md - Creating new CLAUDE.md from scratch
• references/sync-workflow.md - Analyzing code and extracting patterns
• references/organize-and-split-workflows.md - Managing .claude/rules/ structure
• references/modular-organization.md - Modular documentation guide
• references/architecture-patterns.md - Complete architecture pattern guide

Examples

Study these as templates:

• examples/minimal-claude-md.md - Single file example (~200 lines)
• examples/modular-setup/ - Complete modular structure
  • CLAUDE.md (minimal core)
  • .claude/rules/coding-standards.md
  • .claude/rules/architecture.md

Quick Decision Trees

Which Approach?

Project size?
├─ <10k lines → Single file CLAUDE.md
└─ >10k lines → Modular with .claude/rules/

Different rules for different areas?
├─ Yes → Modular (use path patterns)
└─ No → Single file

Which Operation?

Have documentation?
├─ No → Initialize workflow
└─ Yes → Is it outdated?
    ├─ Yes → Sync workflow
    └─ No → Is it >500 lines?
        ├─ Yes → Split workflow
        └─ No → Organize workflow (if want modular)

Which Architecture?

Type of project?
├─ Frontend SPA (React/Vue)
│   ├─ Large (>50k lines) → FSD
│   └─ Medium → Feature-First
├─ Backend API
│   ├─ Go/Java/C# → Package by Feature
│   ├─ Express/Flask/FastAPI → Feature-First
│   └─ Django/Rails → MVC
└─ Unsure → Ask user preferences

Output Examples

Initialize (Single File):

• New CLAUDE.md: 150-250 lines
• English, opinionated baseline
• Core standards + Architecture + Git

Initialize (Modular):

• Minimal CLAUDE.md: 100-150 lines
• Note to run organize workflow next

Sync:

• Updated CLAUDE.md with detected patterns
• Or created/updated .claude/rules/ files
• Summary of changes

Organize:

• .claude/rules/ structure
• Focused files (<200 lines each)
• Updated CLAUDE.md with references

Split:

• Reduced CLAUDE.md (~100-150 lines)
• New .claude/rules/ files
• Better organization

---

All outputs: 100% English, no dynamic data, user-confirmed, ready to use