Claude Source Leaked

Claude Code Unveiled

The first architecture deep-dive, hidden feature catalog, and cost optimization guide for Claude Code — based on v2.1.88 source analysis (1,884 files, 132K lines of TypeScript).

中文版 | English

On March 31, 2026, Claude Code's TypeScript source (1,884 files, ~132K lines) was exposed through an unstripped .map file in the npm package. This repository includes the complete restored source code in src/ plus original analysis. This project extracts actionable insights — architecture patterns, hidden features, cost optimization, and best practices — all with source file references.

Table of Contents

- System Prompt (Complete Reconstruction)
- 87 Hidden Feature Flags
- 15 Hidden Slash Commands
- 25 Internal-Only Commands
- Undercover Mode (How Anthropic Hides AI Attribution)
- Cost Optimization (10 Tips from Source)
- Architecture Diagrams
- Claude Code vs Cursor vs Cline
- Telemetry & Privacy
- Remote Control & Killswitches
- Future Roadmap (Unreleased Features)
- CLAUDE.md Best Practices

System Prompt (Complete Reconstruction)
Full document | Source: src/constants/prompts.ts, src/utils/systemPrompt.ts

5-Layer Priority System

What the Default Prompt Actually Says

The system prompt is 9 major sections:

1. Identity — "You are an interactive agent that helps users with software engineering tasks"
2. System Rules — Tool execution, permission modes, prompt injection detection
3. Task Execution — The most detailed section:
   - Read code before modifying (mandatory)
   - Don't add unrequested features/refactoring
   - Don't create helpers for one-time operations
   - "Three similar lines of code is better than a premature abstraction"
   - Avoid OWASP Top 10 vulnerabilities
4. Careful Actions — Destructive operations need user confirmation (rm -rf,…