Every system reduces to exactly two concept types — levels (accumulations/integrations) and rates (policies governing action) — which suggests splitting any agent runtime into an explicit state store (accumulated memory, backlog, context) and a stateless policy layer that reads state + goals and emits actions. This is a hard architectural boundary, not a metaphor.
Separating accumulators from policies makes agent behavior replayable, diffable, and diagnosable: level equations are audit trails (accounting statements), rate equations are the only place behavior logic lives. It also gives a place to apply consistency checks (the summary's 'dimensional consistency') to agent pipelines rather than treating context and decision-making as one opaque blob.
Any long-running agent or pipeline benefits from an explicit integrator layer (state/memory/queues) decoupled from the decision function, because it converts 'why did it do that' into 'what was the state and what policy read it'.
Every system has only two types of concepts: levels (accumulations) and rates (policies governing actions).
Level equations are integrations (accounting statements of backlog plus incoming orders minus production).