OpenAI

Codex

OpenAI's coding agent across CLI, IDE, ChatGPT and cloud. One of the originators of AGENTS.md, with Skills, MCP and a plugin marketplace.

Apache-2.0TerminalIDEDesktopWeb

Standards support

MCP: supported
MCP

Supported

Source
Agent Skills: supported
Agent Skills

Supported

Source
AGENTS.md: supported
AGENTS.md

Supported

Source
ACP: supported
ACP

Supported

Source

Links

Websitegithub.com/openai/codexMCP setup docsSkills docs

Compare with

Claude CodeGemini CLIOpenCodeCursorGitHub CopilotgooseOpenHandsAmp

Reviewed Oct 5, 2026.