# Checkpoint 5: Seriatim Input Module

## Status

This document describes planned work, not implemented behavior.

## Goal

Add the first real input source while keeping transcript-specific behavior
isolated inside an input-stage module.

This checkpoint should allow Seriatim minimal transcript JSON to become a
generic `SourceDocument`.

## Scope

In scope:

- `internal/modules/input/seriatim`;
- parser for Seriatim minimal output JSON;
- mapping into `SourceDocument` and `SourceUnit`;
- source-document validation;
- input adapter registry wiring;
- module metadata/capabilities for pipeline validation;
- fixtures and tests;
- config compatibility through named pipeline profiles.

Out of scope:

- D&D extraction;
- LLM extraction calls;
- transcript-specific behavior in runner/core packages;
- support for every possible Seriatim schema variant.

## Target End State

The repository should contain a real Seriatim input-stage module that translates
Seriatim minimal transcript JSON into the generic source model.

The Seriatim module should be registered under the stable input adapter key
`seriatim`. It should be selectable through the existing input adapter registry
and through pipeline-profile resolution when a profile binds `input: seriatim`.

The module should accept the Seriatim minimal output shape:

- top-level `metadata`;
- top-level `segments`;
- segment `id`;
- segment `start`;
- segment `end`;
- segment `speaker`;
- segment `text`.

The module should map Seriatim data into generic source values:

- segment `id` becomes `SourceUnit.ID`;
- segment `text` becomes `SourceUnit.Text`;
- the document and unit kind strings identify transcript-like source material
  without adding transcript-specific fields or types to core packages;
- `speaker`, `start`, and `end` become source-unit metadata;
- top-level Seriatim metadata becomes source-document metadata;
- the resulting source document passes core source validation.

The module should reject invalid Seriatim input with clear module-specific
errors. Validation should cover:

- valid JSON;
- required top-level metadata and segments;
- required segment fields;
- unique segment IDs;
- non-empty segment text;
- valid start and end values.

The module should declare flat capabilities for pipeline validation. Initial
capabilities should describe transcript-oriented source properties preserved by
the adapter, including speaker and timestamp metadata.

Implementation staging belongs in
[`implementation.md`](implementation.md).

## Fixtures And Tests

The checkpoint should add synthetic fixtures and focused tests for:

- valid Seriatim minimal transcript;
- malformed JSON;
- missing metadata;
- missing or duplicate segment IDs;
- empty segment text;
- source-reference compatibility with generated unit IDs.

## Done Criteria

- `go test ./...` passes.
- Seriatim minimal transcript JSON maps into `SourceDocument`.
- Transcript fields do not appear in core runner contracts.
- The input module is selectable through the registry and pipeline-profile
  configuration when config support exists.
- The input module declares capabilities needed for pipeline validation.
- Tests prove transcript-specific assumptions are isolated to the input module.

## Review Questions

- Are segment, speaker, and timestamp assumptions contained inside the input module?
- Are unit IDs stable and suitable for source references?
- Does the input module preserve enough metadata for transcript-oriented output later?
- Should the input module accept only Seriatim minimal output for now?