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# Challenge 00: Prepare Your Application and Challenge

**Estimated Time:** 30 minutes

## Introduction

Prepare an application your team owns for a complete rebuild. The target
language, framework, or stack may change after discovery.

## Prerequisites

- An application your team or organization owns, with source access and permission to rebuild it.
- A business/product stakeholder and someone who understands the application.
- The tools and profile selections in the [setup guide](setup.md).

## Description

Choose an application small enough to rebuild and validate within the event.
Rebuild all required functionality. If the app is too large, choose a smaller
one rather than dropping required workflows.

Work in the application repository. Use this prompt to write the rebuild brief:

```text
Help me prepare a complete-app rebuild brief for [application]. Use the source
and evidence I provide to summarize its users, workflows, integrations, data, required
functionality, desired changes, constraints, and decision-makers.
Ask about missing business context and record build/run gaps.
Keep stack preferences as inputs to planning, not target decisions.
Do not edit application code or begin implementation.
```

For a runtime-only change, use the
[upgrade route](../customer/Challenge-00.md).

Follow the [setup guide](setup.md) to install
the plugin and relevant [supporting skills](supporting-skills.md).
Supply source, run notes, contracts, and sanitized database/UI evidence;
record anything unavailable.

Confirm **Claude Opus 5.5** access for implementation and non-production Azure
access for deployment. After target selection, the coach provides matching
infrastructure and a runbook for Challenge 08; the upgrade samples may not fit.

This route does not require the Modernization CLI, Java, or .NET.

## Success Criteria

- [ ] The team owns the application and can access its source and explain its behavior.
- [ ] The brief defines the complete app to rebuild, required functionality, desired changes, constraints, and decision-makers.
- [ ] The app is small enough for the event; any stack preferences are inputs to planning, not assumed decisions.
- [ ] The host finds `azure-app-modernization`, `azure-app-rebuild`, `cloud-architecture-diagram`, and selected supporting skills.
- [ ] Evidence and build/run gaps are noted; inputs contain no secrets or production rows.

## Learning Resources

- [Copilot CLI plugins](https://docs.github.com/en/copilot/reference/copilot-cli-reference/cli-plugin-reference)
- [VS Code agent plugins](https://code.visualstudio.com/docs/agent-customization/agent-plugins)

## Advanced Challenge (Optional)

Identify the business rule or integration most likely to be lost in a rewrite
and how you will verify it in the rebuilt app.