Architecture: [Project Name]

Decision: what was chosen
Alternatives considered: what else was evaluated
Rationale: why this option

Problem and context

What problem this solves and for whom.

Numbered goals with measurable criteria. Explicit non-goals.

Directory layout with one-line descriptions.

One paragraph, then a Mermaid component diagram showing major components, responsibilities, and communication paths.

For each module: what it owns, its public interface, and what it must NOT do. Communication patterns between modules (sync/async, events, RPC).

For each important decision:

Tech stack rules, naming conventions, forbidden libraries, project-wide patterns.

Only unresolved items that must be decided later.