Agent Config Files

Configuration files like CLAUDE.md, .cursorrules, and .github/copilot-instructions.md give agents persistent context about your project's conventions, architecture, and constraints that persist across sessions. These files are checked into your repository and automatically loaded when an agent starts working on your codebase, making them one of the highest-leverage investments in agentic coding because they compound across every interaction without manual effort. The best config files encode the implicit knowledge that senior developers carry in their heads — naming conventions, architectural boundaries, forbidden patterns, file organization rules — transforming tribal knowledge into machine-readable instructions. This concept connects to system prompts as the mechanism config files feed into, context engineering for understanding how this persistent context shapes agent behavior, and IDE agents and CLI agents which each consume config files differently.