Secret: "compile" that orchestration prompt. Determinism is solved by turning prompts into code that can in turn run agents or run code or both.
Everyone misses this pattern with skills: you can just drop code alongside a SKILL.md to guarantee certain behaviors, but for some reason everyone's addicted to writing prompts. You don't even need to build a CLI. A simple skill.py with tasks does it. You can even have helpers that call `claude -p`!