# Internal: Adapters

## Purpose

Explain the adapter interfaces and production composition used by application
and stage orchestration. Externally observable protocols and formats belong in
the [integration contracts](../integrations/).

## Adapter Boundaries

Narratio stage logic depends on adapter interfaces, not transport-specific details.

Primary adapters:

- `whisperx.Client`
- `seriatim.Runner`
- `audita.Runner`
- `scriptorium.Runner`
- `notarius.Runner`
- `storage.ObjectStore`
- `notify.Sender`

## Ownership

Adapters own:

- HTTP/subprocess/SDK argument and transport details.
- Backend-specific request/response mapping.

Adapters do not own:

- stage ordering/skip/force logic;
- manifest transitions;
- canonical path policy.

## Default Wiring

`internal/app/runner.go` initializes default adapters when not injected:

- WhisperX HTTP client from pipeline config.
- Seriatim subprocess runner.
- Audita subprocess runner.
- Scriptorium subprocess runner.
- Noop notifier (`notify.NoopSender`).
- Object store only when required by selected stages/config.

The Notarius subprocess adapter is implemented independently of stage policy;
application composition and extract-stage wiring are not yet implemented.

Object-store construction goes through `newCommandObjectStore`, which loads
configured filesystem secrets before adapter initialization.

## Failure Semantics

- Constructor errors fail stage execution setup early.
- Runtime adapter errors propagate to stage code and then manifest failure handling.
- Subprocess adapters persist stage logs/generated configs through stage-managed paths.

## Implementation And Tests

- Composition: `internal/app/runner.go`, `internal/app/object_store.go`
- Shared subprocess mechanics: `internal/adapters/subprocess`
- Focused adapters: `internal/adapters/{whisperx,seriatim,audita,scriptorium,notarius,storage,notify}`
- `internal/adapters/whisperx/http_test.go`
- `internal/adapters/seriatim/subprocess_test.go`
- `internal/adapters/audita/subprocess_test.go`
- `internal/adapters/scriptorium/subprocess_test.go`
- `internal/adapters/notarius/subprocess_test.go`
- `internal/adapters/storage/*_test.go`
- `internal/app/runner_test.go`

See the [WhisperX](../integrations/whisperx.md),
[Seriatim](../integrations/seriatim.md), [Audita](../integrations/audita.md),
[Scriptorium](../integrations/scriptorium.md), and
[Notarius](../integrations/notarius.md) contracts before changing an
externally visible boundary. Operator-selected values belong in
[Configuration](../config.md).