What is trigger condition action?

Trigger condition action is a concept in personal epistemology: Every agent has a trigger that activates it, a condition that validates it, and an action it takes.

Example: You design an agent for email triage: trigger — a new message lands in your inbox. Condition — the sender is not in your contacts and the subject contains a request. Action — move it to a 'Review Friday' folder. Without the condition, every email gets deferred. Without the trigger, the rule never fires. Without the action, you've built a sensor that watches but never responds. All three components must be present for the agent to function.

This concept is part of Phase 21 (Agent Fundamentals) in the How to Think curriculum, which builds the epistemic infrastructure for agent fundamentals.