AIChat is a command-line tool that aggregates access to over 20 LLM providers including OpenAI, Claude, Gemini, and Ollama. It offers multiple interaction modes: CMD mode for shell-like command execution, REPL mode with tab autocompletion and history, and a Shell Assistant that converts natural language into shell commands. The tool includes RAG capabilities for knowledge retrieval and built-in AI tools and agents for task automation.