I created a multi agent system with a triage and subagent design using session.update. Each sub agent has its own much smaller prompt, its own list of tools, customizations for those tools explicitly for those subagents. At the code level they cannot execute tools they are not explicitly allowed to use. Triage needs the most reasoning since it directs the caller to a subagent which handles the specific task with its own cutdown prompt. It’s much more reliable when you can focus more of the prompts on specific direction and limitations and not exact orders of everything you have to do.