# Internal Component Overview

ConfigKit exposes one supported root `configkit` package. The root owns public
named types, declaration comments, constructors, and explicit conversion/wrapper
code. It delegates loading and frozen inspection to `internal/engine` through
private state; public signatures and fields do not expose engine types.

Implemented component owners:

- `internal/engine` owns host and native-filesystem source acquisition,
  grouped strict composition and recursive precedence assembly, schema
  inspection, decoding, lifecycle coordination, callback auditing,
  provenance/history, passive source-context retention, secret resolution and
  bootstrap, and safe inspection rendering. It never imports the root package.
- Root `Source`, `Filesystem`, `Input`, `Underlay`, `Path`, `Secret`, records,
  lifecycle callbacks, results, and bootstrap reports are root-defined wrappers
  or records. Callback wrappers pass only live engine context during a callback;
  `Result.Config` is detached and its private inspection remains frozen
  independently.
- Root conversion files explicitly cross the path, record, callback, secret, and
  error boundaries. There are no public aliases, anonymous engine embeddings, or
  public engine bridge methods.
- `internal/document` owns the parser-independent ordered tree and cloning.
  `internal/yaml` is the sole upstream YAML adapter and parser/dumper boundary.
- Engine mechanism tests own source, composition, decoding, callback, provenance,
  source-context, secret, history, rendering, and bootstrap behavior. Root tests
  own public API compatibility, facade integration, documentation links, and
  dependency/public boundary checks. Consumer examples remain under
  `examples/consumers`.

Dependency direction is root to engine to document/YAML support. The root may
import only `internal/engine` among project internal production packages; engine
and its supporting packages do not import root. The root boundary test enforces
these constraints and rejects exported aliases, fields, or signatures involving
internal types.

The [configuration contract](../config.md) owns implemented YAML and lifecycle
semantics. The [consumer adoption guide](../consumers/README.md) owns application
guidance. The [architecture policy](../policy/architecture.md) owns contributor
boundaries, and [ADR 0006](../adr/0006-public-facade.md) records the facade
decision. See the [development guide](../development.md) for validation commands
and [release procedure](../release.md) for source-candidate gates.