I've had a LOT of success keeping a "working memory" file for CLI agents. Currently testing out Codex now, and what I'll do is spend ~10mins hashing out the spec and splitting it into a list of changes, then telling the agent to save those changes to a file and keep that file updated as it works through them. The crucial part here is to tell it to review the plan and modify it if needed after every change. This keeps the LLM doing what it does best (short term goals with limited context) while removing the need to constantly prompt it. Essentially I feel like it's an alternative to having subagents for the same or a similar result