Claude Code's Dual Control System: When CLAUDE.md and settings.json Matter Most

Distinguishing between CLAUDE.md and settings.json is critical for Claude Code users seeking to configure their development environment effectively. CLAUDE.md functions as instructions to Claude's reasoning—style preferences, project context, and coding conventions—while settings.json enforces hard constraints on tool access and command execution. This fundamental difference means safety-critical rules must live in settings.json as unbreakable restrictions, not just suggestions, preventing dangerous configurations and ensuring both productivity and security.