# Integration: Seriatim

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

## Adapter Boundary
Interface:
- `seriatim.Runner`
- methods:
  - `Run(ctx, MergeRequest)`
  - `Normalize(ctx, NormalizeRequest)`
  - `Trim(ctx, TrimRequest)`

Primary implementation:
- `internal/adapters/seriatim/SubprocessRunner`

Execution modes:
- `seriatim merge`
- `seriatim normalize`
- `seriatim trim`

## 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.

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;
- subprocess failure;
- invalid JSON outputs;
- missing `segments` array for normalize/trim transcript outputs.

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.

## Config Mapping
Config fields consumed through runner/stage wiring are under `pipeline.seriatim.*`.

Maintained examples with Seriatim config:
- `examples/pipeline.full.annotated.yml`
- `examples/pipeline.production.yml`