What is shared state between agents?

Shared state between agents is a concept in personal epistemology: When agents need to share information define clearly how that information flows.

Example: You run a morning system with three agents: a planning agent that sets your daily priorities, a calendar agent that blocks time for deep work, and an energy-tracking agent that logs how you felt after each work block. Each agent does its job. But none of them can see what the others produced. The planning agent sets priorities without knowing your energy patterns. The calendar agent blocks time without knowing today's priorities. The energy tracker logs data that never reaches the planner. You have three competent agents operating on three private realities. Compare this to a version where all three agents read from and write to a shared daily state — a single document containing today's priorities, the current calendar, and yesterday's energy data. Now the planner accounts for energy patterns. The calendar respects priority order. The energy tracker's output feeds tomorrow's planning. Same agents, same capabilities. The difference is shared state.

This concept is part of Phase 26 (Multi-Agent Coordination) in the How to Think curriculum, which builds the epistemic infrastructure for multi-agent coordination.