alejandrobalderas/claude-code-from-source

Architecture, patterns & internals of Anthropic's AI coding agent — reverse-engineered from source maps

# Claude Code from Source **Architecture, Patterns & Internals of Anthropic's AI Coding Agent** Read online at claude-code-from-source.com --- > **This repository is purely educational.** It contains no source code from Claude Code — not a single line. Every code block is original pseudocode written to illustrate architectural patterns. The goal is to help engineers understand how production AI agents are built, not to reproduce or redistribute proprietary software. --- When Anthropic shipped Claude Code on npm, the `.js.map` source maps contained a `sourcesContent` field with the full original TypeScript. This book is the result of studying that architecture and distilling the patterns, trade-offs, and design decisions into a technical narrative that any engineer can learn from. **18 chapters across 7 parts.** ~400 pages in print equivalent. Every chapter has layered depth: a narrative flow for technical leaders, deep-dive sections for implementers, and an **"Apply This"** closing that extracts transferable patterns you can steal for your own systems. Diagrams use [Mermaid](https://mermaid.js.org/) and render natively on GitHub. --- ## Who This Is For - **Senior engineers building agentic systems** — steal the patterns, understand the trade-offs, implement in your own stack - **Technical leaders evaluating architectures** — follow the narrative without reading every code block - **Anyone curious about how production AI tools actually work** under the hood --- ## Table of Contents ### Part I: Foundations *Before the agent can think, the process must exist.* | # | Chapter | What You'll Learn | |---|---------|-------------------| | 1 | [The Architecture of an AI Agent](./book/ch01-architecture.md) | The 6 key abstractions, data flow, permission syste