Aider is an AI-powered command-line tool that facilitates pair programming by integrating large language models (LLMs) directly into your terminal. It allows developers to collaboratively edit code within their local git repositories, supports multiple programming languages, and offers seamless integration with various editors and IDEs. Aider automates git commits with descriptive messages, assists in adding new features, debugging, refactoring code, and updating documentation, thereby streamlining the development workflow.