prd-to-issues

name	prd-to-issues
description	Break a PRD into independently-workable issues and write each as a local markdown file in issues/. Use when the user wants to turn a PRD into a list of concrete tasks.

PRD to Issues

Break a PRD into independently-grabbable issues using vertical slices (tracer bullets), written as local markdown files under issues/.

Project context

In this codebase a "vertical slice" usually cuts across the C# stage and the Python stage:

• C# side: a new/changed command handler under RaceDataDownloader/Commands/<Verb>/, possibly new domain types in RacePredictor.Core, paired tests in RaceDataDownloader.Tests / RacePredictor.Core.Tests (xUnit + Verify snapshots).
• CSV schema: any new columns in Results_YYYYMM.csv, Race_Features.csv, Horse_Stats.csv, etc.
• Python side: matching changes to the relevant script under Data/ (FeatureAnalysis, HorseStatsBuilder, JockeyStatsBuilder, LinearRegressionPredictor).
• Pipeline glue: run.ps1 wiring if a new verb or step is introduced.

A complete slice is verifiable by running .\run.ps1 (or a focused subset of it) and seeing the new behavior produce the expected file output.

Process

1. Locate the PRD

Ask the user for the PRD file path (e.g. issues/prd.md).

If the PRD is not already in your context window, read it from the file.

2. Explore the codebase (optional)

If you have not already explored the codebase, do so to understand the current state of the code — especially the existing verbs in RaceDataDownloader/Commands/, the CSV schemas they produce, and which Data/*.py scripts consume those CSVs.

3. Draft vertical slices

Break the PRD into tracer bullet issues. Each issue is a thin vertical slice that cuts through ALL integration layers end-to-end, NOT a horizontal slice of one layer.

Slices may be 'HITL' or 'AFK'. HITL slices require human interaction, such as an architectural decision or a design review. AFK slices can be implemented and merged without human interaction. Prefer AFK over HITL where possible.

- Each slice delivers a narrow but COMPLETE path through every relevant layer (C# handler + tests, CSV schema, Python consumer if any, `run.ps1` wiring) - A completed slice is demoable on its own — running the affected verb or `.\run.ps1` produces a visibly different file - Prefer many thin slices over few thick ones (e.g. "add JockeyId to RaceCardRecord" before "use JockeyId in LinearRegressionPredictor")

4. Quiz the user

Present the proposed breakdown as a numbered list. For each slice, show:

• Title: short descriptive name
• Type: HITL / AFK
• Blocked by: which other slices (if any) must complete first
• User stories covered: which user stories from the PRD this addresses

Ask the user:

• Does the granularity feel right? (too coarse / too fine)
• Are the dependency relationships correct? (e.g. does the Python feature change actually need the C# schema change to land first?)
• Should any slices be merged or split further?
• Are the correct slices marked as HITL and AFK?

Iterate until the user approves the breakdown.

5. Create the issue files

For each approved slice, write a markdown file in issues/ using the naming pattern issues/NNN-short-title.md (e.g. issues/004-add-jockey-id-to-racecard-record.md).

Number issues starting from the next available number (check what files already exist in issues/).

Create files in dependency order (blockers first) so you can reference real filenames in the "Blocked by" field.

Do NOT use gh issue create or any GitHub CLI commands. Do NOT reference GitHub issue numbers. Use local filenames for all cross-references.

## Parent PRD

issues/prd.md (or whichever PRD file was used)

What to build

A concise description of this vertical slice. Describe the end-to-end behavior, not layer-by-layer implementation. Reference specific sections of the parent PRD rather than duplicating content. If the slice touches both the C# and Python halves, name the verb / script affected.

Acceptance criteria

• Criterion 1 (e.g. RaceDataDownloader.exe <verb> --output Data produces a CSV with column X)
• Criterion 2 (e.g. the matching *.Tests project has a new Should test asserting on the Verify snapshot)
• Criterion 3 (e.g. Data/<Script>.py reads/writes the new column without erroring on existing fixture data)

Blocked by

• Blocked by issues/NNN-title.md (if any)

Or "None - can start immediately" if no blockers.

User stories addressed

Reference by number from the parent PRD:

• User story 3
• User story 7

Do NOT close or modify the parent PRD file.