Liu's 4 Lines Are the Floor. Build the Ceiling.

Yanli Liu's " The 4 Lines Every CLAUDE.md Needs " makes a real point. The 4 lines, derived from Andrej Karpathy's January 2026 thread on agent failure modes, all express the same insight: behavioral rules outperform feature rules. Don't assume. Surface tradeoffs. Minimum code that solves the problem. Touch only what you must. Define success criteria. Loop until verified. Each one is portable across stacks and tasks, where prescriptive rules go stale the moment your codebase shifts. The 4 lines a