# Architecture overview

```mermaid
flowchart LR
  Bootstrap[bootstrap / composition root] --> Presentation[presentation]
  Bootstrap --> Adapters[adapters]
  Presentation --> Application[application]
  Adapters --> Application
  Application --> Domain[domain]
  Contracts[contract registries] --> Bootstrap
  Contracts --> Adapters
  Contracts --> Presentation
```

Dependencies point inward. Presentation calls application use cases, adapters
implement application ports, and only the composition root selects concrete
adapters. Contract registries are the single named source for routes, API
operations, environment values, storage keys, errors, queries, telemetry, and
release tokens.