Codex autonomously multiplied work across worktrees/subagents, exhausted weekly quota, then aborted the active turn

Summary

Codex exhausted almost an entire freshly reset weekly usage allowance in roughly two hours while executing a development workflow across three parallel worktrees. Post-incident analysis showed that each worktree also used its own subagents.

I requested that the implementation be performed in small, controlled pieces. I did not request an especially expensive multi-agent strategy, nor did I explicitly ask Codex to multiply each worktree into