Deep Dive Claude Code

English | 中文

Production-grade Claude Code has 960+ files, 50+ integrated tools, and 380K+ lines of code. These 13 chapters take you from the core loop to the full engineering picture, layer by layer.

👉 Live Demo

📚 13-Chapter Learning Path

Phase 1: Core Loop                  Phase 2: Security
========================          ========================
Ch01  Agent Loop          ★★★    Ch04  Shell Security      ★★★
      The essence of all Agents         300KB+ security code
      |                                 |
Ch02  Tool System         ★★☆    Ch05  Permission Engine   ★★☆
      50+ tool registration             Every op is checked
      |
Ch03  Prompt Engineering  ★★☆
      Dynamic assembly pipeline

Phase 3: Context & Extensions       Phase 4: Collaboration & Eng.
========================          ========================
Ch06  Context Management  ★★★    Ch09  Multi-Agent         ★★☆
      Infinite work in finite ctx       Agent/Team/Swarm
      |                                 |
Ch07  MCP Protocol        ★★☆    Ch10  CLI Transport       ★☆☆
      Unified tool-call standard        SSE/WS/Hybrid
      |                                 |
Ch08  Plugin Ecosystem    ★☆☆    Ch11  Bootstrap Optim.    ★☆☆
      Extensible capabilities           Fast path + prefetch
                                        |
                                  Ch12  Production Patterns ★★★
                                        Demo → Production

Phase 5: Hidden Features
========================
Ch13  Hidden Features     ★★★
      Buddy · Kairos · Ultraplan
      Undercover · Daemon · UDS

📖 About

This project is based on the source code of Claude Code. Through 13 progressive chapters, it helps developers understand the internal architecture and engineering decisions of a production-grade AI coding assistant.

The project consists of three core parts:

Part	Description
📖 Deep-dive Docs (docs/)	13 source code analysis documents, each focusing on a core subsystem
💻 Runnable Demos (agents/)	12 TypeScript demo programs, each independently runnable
🌐 Interactive Platform (web/)	Next.js web app with visualizations, simulator, and source viewer

📋 Chapter Index

Ch	Title	Motto	Key Source Files
Ch01	Agent Loop	The essence of all Agents is a loop	QueryEngine.ts + query.ts
Ch02	Tool System	Register a handler, gain an ability	Tool.ts + tools.ts
Ch03	Prompt Engineering	System Prompt is a dynamically assembled pipeline	prompts.ts + claudemd.ts
Ch04	Shell Security	The most powerful tool needs the tightest defense	bashSecurity.ts + bashParser.ts
Ch05	Permission Engine	Permissions are the skeleton, not an afterthought	permissions.ts + filesystem.ts
Ch06	Context Management	Context always fills up — the key is how to compress	compact.ts + SessionMemory/
Ch07	MCP Protocol	MCP turns any service into an AI tool	mcp/client.ts + mcp/auth.ts
Ch08	Plugin Ecosystem	Plugins are capability multipliers	pluginLoader.ts
Ch09	Multi-Agent	Scale comes from division of labor, not bigger context	AgentTool.tsx + swarm/
Ch10	CLI Transport	The transport layer decides where an Agent can run	cli/transports/
Ch11	Bootstrap Optimization	Fast path defines experience, full path defines capability	dev-entry.ts → cli.tsx → main.tsx
Ch12	Production Patterns	Making an Agent reliable takes 10x the engineering	sessionStorage.ts + analytics/
Ch13	Hidden Features	Every feature('FLAG') line hides a product decision	buddy/ + ultraplan.tsx + undercover.ts

🚀 Getting Started

Web Platform (Recommended)

cd Deep-Dive-Claude-Code/web
npm install
npm run build    # Compile docs + source → build
npm run dev      # http://localhost:3200

Each chapter page has 4 tabs:

• Visualization — Interactive step-by-step animations (13 components)
• Simulator — Agent loop message replay (13 scenarios)
• Source — Key code snippets with TypeScript syntax highlighting
• Deep Dive — Full Markdown document rendering

Source file cards on the home page are clickable and jump to the source viewer with search highlighting.

CLI Demos

cd Deep-Dive-Claude-Code
npm install
npx tsx agents/s01_agent_loop.ts    # Requires API Key
npx tsx agents/s04_bash_security.ts # No API Key needed — try this!

📁 Project Structure

Deep-Dive-Claude-Code/
├── README.md                        # This file (English)
├── README.zh-CN.md                  # 中文版
├── imgs/                            # Screenshots
│
├── docs/                            # 📖 13 deep-dive documents
│   ├── ch01-agent-loop.md
│   ├── ch02-tool-system.md
│   ├── ch03-prompt-engineering.md
│   ├── ch04-bash-security.md
│   ├── ch05-permissions.md
│   ├── ch06-context-management.md
│   ├── ch07-mcp-protocol.md
│   ├── ch08-plugin-ecosystem.md
│   ├── ch09-multi-agent.md
│   ├── ch10-cli-transport.md
│   ├── ch11-bootstrap.md
│   ├── ch12-production-patterns.md
│   └── ch13-hidden-features.md
│
├── agents/                          # 💻 12 runnable demo programs
│   ├── s01_agent_loop.ts
│   ├── ...
│   └── s12_production.ts
│
├── source-code/                     # 📂 Core source files (from main repo)
│   ├── QueryEngine.ts
│   ├── query.ts
│   ├── Tool.ts
│   ├── constants/prompts.ts
│   ├── tools/BashTool/
│   ├── tools/AgentTool/
│   ├── utils/permissions/
│   ├── services/mcp/
│   └── services/compact/
│
├── web/                             # 🌐 Next.js interactive platform
│   ├── src/
│   │   ├── app/                     # Pages (home, chapters, architecture, source viewer)
│   │   ├── components/              # Visualizations, simulator, layout, docs renderer
│   │   ├── hooks/                   # useSteppedVisualization + useSimulator
│   │   ├── data/                    # Scenarios JSON + generated docs/sources
│   │   └── lib/                     # Constants + utilities
│   └── scripts/                     # Build scripts (docs→JSON, sources→JSON)
│
├── package.json                     # agents/ dependencies
└── .env.example                     # API Key template

🛠️ Tech Stack

Learning Platform (web/)

Technology	Purpose
Next.js 15	React framework, App Router
Tailwind CSS 4	Dark theme styling
Framer Motion	Interactive animations
Lucide React	Icon library
unified + remark + rehype	Markdown rendering pipeline

Analyzed Project (Claude Code)

Layer	Technology
Runtime	Bun 1.3.5+
Language	TypeScript (~960 .ts/.tsx files)
Terminal UI	React Ink
CLI Framework	Commander.js
Tool Protocol	MCP (Model Context Protocol)
A/B Testing	GrowthBook
Compile-time Elimination	feature() macro (bun:bundle)

🙏 Acknowledgments

This project would not exist without the following open-source projects:

• claude-code-rev — Claude Code source restoration project providing complete TypeScript source code with local build support. All source code analyzed in this project originates from here.
• claw-code — Pioneer in Claude Code source analysis, providing excellent analysis approaches and documentation references.
• claudecode-src Wiki — Comprehensive file-by-file Claude Code source analysis Wiki.
• learn-claude-code — Interactive Agent teaching project. The web platform's interaction patterns (stepped visualization + agent simulator + source viewer) were inspired by this project.

Thank you to all the authors and contributors!