# Integration: Seriatim

## Purpose
Define the Seriatim adapter contract used by `merge`, `normalize`, `trim`, and `render`.

## External Boundary

Narratio invokes Seriatim as a subprocess in these modes:

- `seriatim merge`
- `seriatim normalize`
- `seriatim trim`
- `seriatim render`

The configured timeout and parent cancellation bound each invocation. Internal
runner composition is documented in
[the adapter implementation guide](../internal/adapters.md).

## Request/Result Contracts
- `MergeRequest`/`MergeResult`: multi-input merge to base transcript, optional report.
- `NormalizeRequest`/`NormalizeResult`: transcript normalization with explicit schema.
- `TrimRequest`/`TrimResult`: transcript trimming with required keep selector.
- `RenderRequest`/`RenderResult`: transcript-to-markdown rendering with explicit format and render booleans.

Results include output/log/config paths, timing, exit code, and metadata.

## Validation and Failure Semantics
Runner construction validates:
- binary presence;
- timeout > 0;
- supported output schema (`seriatim-minimal|seriatim-intermediate|seriatim-full`);
- non-negative coalesce gap.

Invocation fails on:
- missing required request paths/inputs;
- invalid normalize schema override;
- unsupported render format;
- subprocess failure;
- invalid JSON outputs for merge/normalize/trim;
- missing `segments` array for normalize/trim transcript outputs;
- empty render output files.

When report paths are provided/enabled, report files must parse as JSON.

## Deterministic Behavior
- argument ordering is deterministic per command construction.
- merge env overrides are explicit (`SERIATIM_*`) and only emitted when configured.
- generated invocation YAML (`seriatim.generated.v1`) is emitted when requested.
- adapter does not write manifests or choose stage inputs.

## Configuration

Operator-selected values are defined under `pipeline.seriatim.*` and
`pipeline.render.*` in the
[configuration reference](../config.md#pipeline).

Maintained examples with Seriatim config:

- [Full annotated pipeline](../../examples/pipeline.full.annotated.yml)
- [Production-shaped pipeline](../../examples/pipeline.production.yml)