Architecture
Most architecture diagrams mix levels and hide what the arrows mean. C4 gives agent projects four zoom levels. Use the tabs to walk from the whole system down to the code.
Nov 6, 2026 · 6 min read
Agent projects change shape quickly: a tool gateway appears, memory moves to its own store, a second model provider is added. The diagram on the wiki usually stops matching the system within weeks, and it often never answered the first question a new teammate asks: what are the parts, and who talks to whom?
The C4 model, created by Simon Brown, describes software at four levels of zoom: software system, container, component and code. The C4 site is explicit that you do not have to use every level, and that system context and container diagrams are enough for most teams.
Use the tabs above to move between the levels. They show the same sample agent platform, each one zoomed in a step further.
A container is something that has to be running for the system to work: a web app, an agent service, a tool gateway, a database. The model provider and the business systems are not ours, so they are drawn as external systems outside the boundary.
Store the diagram source in the repository and review it in the same pull request as the change it describes. A diagram that is edited with the code stays honest. One that lives only in a slide deck does not.
Tell us about one process. We will show how an agent could handle it, and what to measure to know it works.