> ## Documentation Index
> Fetch the complete documentation index at: https://akron-cdb9eaf4.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Public architecture

> Understand Akron's public architecture, runtime boundaries, settings flow, policy gates, and verification surfaces.

Akron is structured around several core public concepts: overlay UI, persisted settings, `.akr` packs, policy gates, runtime services, capture/proof output, and verification tests.

## System Shape

```mermaid theme={"theme":{"light":"github-light","dark":"github-dark"}}
flowchart TD
  overlay["Overlay UI"] --> settings["Settings"]
  settings --> policy["Policy"]
  policy --> runtime["Runtime"]
  settings --> packs[".akr packs"]
  runtime --> capture["Capture and proof"]
  runtime --> interop["Interop"]
  tests["Verification"] --> policy
  tests --> packs
  tests --> runtime
```

## Main Boundaries

| Boundary     | Responsibility                                                                                                                                                                                                                                    |
| ------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| Overlay      | Presents rows, actions, popups, search, policy badges, and feature-specific browsers. Large browser surfaces, complex popup editors, fallback rendering, search, action binding, and layout helpers live in focused overlay partials.             |
| Settings     | Stores user-configurable values and persisted setup state. Setup capture, setup application, HUD settings, defaults, clamps, display helpers, and recorder settings live in focused partials.                                                     |
| Policy       | Classifies features and records or blocks use under active policy.                                                                                                                                                                                |
| Runtime      | Applies gameplay, visual, capture, interop, proof behavior, and module lifecycle hooks. Feature-family runtime, command, HUD, save/load, recorder, and inspector logic should live beside that feature family instead of in the core module file. |
| `.akr` packs | Exports/imports scoped settings. Setup archive contracts and section copying live in the setup-pack service; OS-specific file picker process launching lives in a focused setup file-picker partial.                                              |
| Tests        | Enforce registry coverage, defaults, archive safety, and behavior contracts.                                                                                                                                                                      |

## Policy Calls

Use the policy system according to intent:

* Use `TryUse` when behavior should count as feature use.
* Use `CanUse` when code only needs to decide whether a surface should render or be available.
* Use registry lookups for tooltip badges and static policy display.

For detailed source ownership, see [Implementation boundaries](/contributing/implementation-boundaries).