OpenAI Codex CLI

OpenAI's lightweight open-source coding agent that runs in your terminal.

Guides & comparisons

Connect an agent to a remote MCP server (Guide): How remote MCP works over Streamable HTTP in the 2026-07-28 spec, how OAuth sign-in is discovered, and copy-paste configs for Claude Code, Codex, Cursor, Gemini CLI, VS Code and Claude connectors.
Terminal coding agents compared (Comparison): Claude Code, Codex CLI, Gemini CLI, GitHub Copilot CLI, OpenCode, Cline, goose and Aider compared on license, model access, instruction files, sandboxing, headless mode, MCP and Agent Skills support.
Coding agent starter stack (Stack): A terminal coding agent plus current library docs, GitHub access, a real browser and a sandbox, connected over MCP, with the configuration choices that keep it safe.
Connect a remote MCP server (Skill): Configure, verify and troubleshoot a remote Streamable HTTP MCP server in the major agent clients, including OAuth discovery and protocol-version checks.
Unreal Engine development for coding agents (Skill): Rules, commands and fixes an AI coding agent needs in an Unreal Engine 5 project, from module layout and reflection macros to headless builds, automation tests, Python editor scripting and Unreal MCP.