weatherreporter/docs/internal/prompt-input.md

# Prompt Input Internals

This document describes prompt input data package construction.

## Purpose

`internal/promptinput` converts a structured briefing package and optional
Recent Changes into the `data_package` JSON passed to Scriptorium prompts.

## Inputs And Outputs

Inputs:

- `briefing.Package`
- optional `[]changes.Change`

Outputs:

- `promptinput.Package` containing schema version, RunID, report metadata,
  briefing content, Recent Changes, and source warnings. Briefing content
  includes configured location context, current conditions when available,
  discussion key messages, and short/long-term AFD narratives when the Weather
  API provides them.
- report metadata includes `currentLocalDate`, the generation date formatted as
  `YYYY-MM-DD` in the effective report timezone.
- optional JSON file written by `promptinput.Save`

## Boundaries

- This package owns the prompt input schema and validation.
- It does not fetch weather data, derive forecast summaries, find prior
  snapshots, compare changes, or invoke Scriptorium.

## Config Fields Used

None directly. Config-derived values, including timezone and prompt location
context, are already present in briefing metadata before this package runs.

## External Adapters Used

None.

## State Or Manifest Behavior

`promptinput.Save` writes JSON atomically. Managed workspace paths are owned by
`internal/state`.

## Skip And Resume Behavior

None. Recent Changes is always present as an `items` list and may be empty.

## Failure Behavior

Validation fails before render preflight when required top-level or briefing
metadata fields are missing or inconsistent, or when no report content is
present. Save failures include filesystem operation and path context.

## Tests

Inspect:

- `internal/promptinput/package_test.go`
- `internal/app/app_test.go`

## Invariants

- Scriptorium receives structured `data_package` JSON.
- Briefing metadata and top-level report metadata must agree.
- Recent Changes are not inferred from rendered report text.