Codex
OpenAI
Codex CLI is OpenAI's Apache-2.0 licensed terminal coding agent. It reads your local codebase, edits files, runs sandboxed shell commands, and iterates via natural language. Tuned for GPT-5.x models and available free to ChatGPT Free/Go subscribers. Supports MCP and integrates with the Agent Client Protocol (ACP).
Free for ChatGPT Free/Go subscribers (for a limited time). API billing applies for direct API key usage.
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