Claude Code's .claudeignore: The Overlooked Security Feature Every Developer Needs

Claude Code reads all project files by default, exposing sensitive credentials and wasting context window on massive vendor directories like node_modules, creating both security and performance problems. The .claudeignore file—using gitignore-style syntax—solves both issues by excluding unnecessary files and protecting secrets while allowing Claude to focus on your actual code. For any developer using Claude Code, implementing .claudeignore is a critical but often overlooked step that dramatically improves security posture and AI response quality.