What is agent communication protocols?

Agent communication protocols is a concept in personal epistemology: Define how the output of one agent becomes the input of another.

Example: You have a morning routine with three agents: a planning agent that decides what to work on, an execution agent that does the work, and a review agent that evaluates the output. Each agent does its job well in isolation. But the planning agent produces a vague intention ('work on the project'), the execution agent interprets it differently than intended, and the review agent evaluates against criteria the planner never specified. Three capable agents, zero coordination — because nobody defined the protocol. The output of one agent does not cleanly become the input of the next. Compare this to a system where the planning agent outputs a structured brief (task, success criteria, time constraint, context from yesterday), the execution agent receives that brief and produces a deliverable tagged with which criteria it addressed, and the review agent scores the deliverable against the original criteria and passes a structured assessment back to the planner. Same three agents. But now they speak a shared protocol, and the system actually works.

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.