Enrico Pezzano enriicola

Inside the Claude Code source

Anthropic's Claude Code CLI source code leaked onto GitHub recently. All of it. About 1,900 files and a lot of TypeScript.

I read through the key modules. What follows is a breakdown of the surprising parts: how the system actually works, where Anthropic made clever engineering choices, and where their approach diverges from OpenAI's Codex in ways you wouldn't guess from using either tool.

Lifecycle of a request

Here's what happens when you type a message into Claude Code:

	# ===========================================
	# ZSH Hacks - Dreams of Code
	# ===========================================
	# Add these to your .zshrc file
	# ===========================================

	# -------------------------------------------
	# 1. Edit Command Buffer
	# -------------------------------------------
	# Open the current command in your $EDITOR (e.g., neovim)