Shared substrates

A shared substrate is the medium a group of agents reads from and writes to in order to coordinate without talking directly. Pheromone for ants. Price for markets. A task board for a swarm of coding agents.

I’ve become convinced the substrate is where most of the design leverage lives. Given a good substrate, mediocre agents coordinate well. Given a bad one, excellent agents thrash. The substrate sets the channel: what can be said, how long it persists, how it decays, who can see it.

Two parameters do most of the work — persistence (how long a trace lasts) and reinforcement (whether good traces get amplified). Tune those and emergence is mostly a consequence.

The practical upshot for software: stop optimizing the agents first. Optimize the artifact they share.