What does it mean that internal agents versus external agents?

Internal agents run in your mind while external agents are embedded in tools and systems.

Example: You have an internal agent that fires when a colleague says 'this should be quick' in a meeting — it triggers suspicion and prompts you to ask for a time estimate. You also have an external agent: a calendar reminder every Friday at 4pm that triggers a weekly review. Both are agents. One runs on neurons, the other runs on software. Both reliably produce action from a trigger without requiring you to remember or decide in the moment.

Try this: List five agents currently operating in your life. For each one, label it internal (runs in your head) or external (embedded in a tool, environment, or system). Then ask: which internal agents are unreliable enough that they should be externalized? Which external agents have you internalized so deeply that the tool is now redundant? This audit reveals where your cognitive architecture is fragile and where it is robust.