Subagents are amazing tools for managing context, among other things. But Codex CLI doesn't have them. Let's change that!

Brian John is a Principal Full Stack Engineer with over a decade of experience in technology. He is currently working on using AI to help his R&D team members ship faster and with higher quality.

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AI Engineer

A technical walkthrough of implementing sub-agents in Codex CLI to enable multi-agent workflows similar to Claude Code. The implementation uses a wrapper script architecture where a parent Codex session spawns child Codex instances as sub-agents, managing context windows and permissions. Key challenges include navigating Codex's sandbox permissions, handling OpenAI credentials, and ensuring the command structure remains consistent to avoid repeated permission prompts. The solution includes a 72-line wrapper script and agent executor class that manages reasoning effort levels and file-based communication between agents.

Hacking Subagents Into Codex CLI — Brian John, Betterup