What Are Subagents? Comparing OpenAI Codex, Claude Code, and Gemini CLI
Key Takeaways - Subagents are smaller AI tools that each handle one part of a larger task. - OpenAI Codex is the clearest match for the term because OpenAI explicitly documents subagent workflows and says Codex is designed for multi-agent workflows. - Claude Code also supports agent teams, but Anthropic describes them as multiple Claude Code agents rather than subagents. - Gemini CLI is an open-source AI agent for the terminal that uses built-in tools and MCP servers for multi-step work. - Subagents are smaller AI tools that each handle one part of a larger task. That might mean one tool searches a codebase, another edits files, and another checks whether the changes worked. Instead of asking one AI system to manage everything at once, the work gets split into smaller parts. For people who do not know much about AI, that is the easiest way to think about subagents. OpenAI Codex, Claude Code, and Gemini CLI all help with coding work, but they do not present this idea in exactly the sa...