Pattern: Claude Code Built with Claude Code — Source Leak Confirms 49 Agent Persona Files and Recursive Bootstrapping Architecture

r/ClaudeAI / GitHub·high signal

The leaked source code confirms Anthropic builds Claude Code using Claude Code itself. The agents/ directory contains 49 markdown files — personality profiles for specialized AI personas including harness, plan, security, and explore agents. This is concrete evidence of recursive self-improvement in production at the tool level: the agents that power the coding tool are defined as markdown specs that Claude Code can read and iterate on. For builders: this validates the CLAUDE.md-as-architecture pattern and suggests markdown agent definitions will become the standard composition primitive.