Design around the work
Start with the responsibilities the system needs to fulfil. Which information belongs together? Which decisions change for different reasons? A useful boundary makes these responsibilities clear to the people building and operating the software. It should be understandable before it becomes a deployment diagram.
Choose complexity deliberately
Splitting an application into services can create independent deployment boundaries, but it also introduces network communication and operational work. A modular application can be a sensible starting point when the team and problem do not yet require that separation. Record the reasons for the choice and the conditions that would justify revisiting it.
Treat interfaces as agreements
Document the inputs, outputs, failure behaviour, and ownership of each interface. Consider how an existing consumer will behave when a field or rule changes. A small explicit contract is often easier to maintain than an assumption scattered across several codebases.
Leave a trail of decisions
Keep short architecture decision records that explain the problem, the options considered, and the trade-off accepted. Include the context that might change. The aim is to make future decisions easier, not to defend an old diagram indefinitely.
Questions for the next review
Ask what the team can change independently, where knowledge is concentrated, and which failures are difficult to diagnose. These questions make architecture a practical part of delivery. This note sets out design considerations; it does not describe a measured Vadersoft client outcome.