Anatomy of Claude Code: File and Folder Sizes

Overview

The Claude Code source distribution (claude-code-source) contains 3 folders and 7 files at its top level. Here’s what’s inside and how much space each item takes up.

Size Breakdown

Total: ~163M

Where the Weight Lives

pie title Space Distribution
    "cli.js.map" : 57
    "src/" : 35
    "node_modules/" : 29
    "vendor/" : 29
    "cli.js" : 13
    "Other" : 0.12

📦 The Bundle: cli.js + cli.js.map (70M combined)

The single bundled entry point cli.js weighs 13M — the entire application compiled into one JavaScript file. Its companion source map cli.js.map is the largest item at 57M, roughly 4.4× the bundle itself. This is typical for source maps, which store full mapping data back to the original TypeScript sources.

🗂️ Source Code: src/ (35M)

The src/ directory holds the original TypeScript source, organized into modules:

• Core — Tool.ts, Task.ts, QueryEngine.ts, context.ts
• UI — components/, screens/, ink/ (Ink-based terminal UI)
• CLI — cli/, commands/, entrypoints/, main.tsx
• Features — skills/, hooks/, keybindings/, voice/, vim/
• Infrastructure — services/, server/, remote/, state/, migrations/
• Agent/AI — assistant/, coordinator/, query/, bridge/, buddy/
• Memory — memdir/

📚 Dependencies: node_modules/ + vendor/ (58M combined)

The two dependency directories account for about 36% of total size. node_modules/ holds npm packages while vendor/ contains vendored third-party code.

📄 Small Files (< 1M)

The remaining files — LICENSE.md, README.md, bun.lock, package.json, and sdk-tools.d.ts — are all under 120K. The sdk-tools.d.ts type definition file at 116K is the notable one, providing TypeScript type definitions for SDK tooling.

Key Takeaways

• ✅ The source map alone (cli.js.map) accounts for 35% of total size — it’s a development/debugging artifact, not needed at runtime
• ✅ Without the source map, the distribution drops to ~106M
• ✅ The actual application bundle (cli.js) is a single 13M file — relatively lean for a full-featured CLI agent
• ✅ Source code (src/) is larger than the bundle, suggesting significant tree-shaking or dead code elimination during build