OpenAI Codex CLI
OpenAI Codex CLI is an open-source terminal agent that applies natural language instructions to your local codebase. Running in your terminal, it reads files, writes code, runs tests, and iterates until the task is complete — powered by OpenAI's o4-mini model.
Claude Code
Terminal-first agentic coding assistant from Anthropic. Full MCP client support, codebase-aware, runs multi-step tasks autonomously.