Testing OpenAI Codex and Comparing It to Claude Code

OpenAI Codex is a command-line AI coding assistant that focuses on experienced developers rather than beginners. The tool requires API key setup and works through terminal interactions, asking for permission before making destructive changes. In a practical test involving JSON file merging with specific requirements about preserving image references, Codex successfully completed the task using sed commands, though it provided less transparent planning compared to competitors like Claude Code. The tool shows promise for experienced developers who understand the underlying commands it executes.