Claude Code

TL;DR

Anthropic's production AI coding agent — 510K lines of TypeScript on Bun, 40+ tools as pure functions, one 1,729-line query.ts running the whole show. The 4-layer context cascade (lossless deletion → cache hiding → structured archival → full compression) is the most sophisticated context management in a shipping agent.

Key Finding: 4-layer context cascade, hidden pet system (18 species)