Notes on building — Austin Kim https://austinjuliuskim.com/blog Working notes on AI-native tooling — what I built, what it measured, and what broke. en The 80% I couldn't cut https://austinjuliuskim.com/blog/context-engineering-claude-5 https://austinjuliuskim.com/blog/context-engineering-claude-5 Sun, 26 Jul 2026 00:00:00 GMT Anthropic deleted 80% of Claude Code's system prompt with no measured performance loss. I counted mine: 1,984 lines across four locations, several of them unsatisfiable.