# Legacy Modernization Readiness Checklist

> Classification: **SYNTHETIC DEMO**. This checklist is a work sample, not a client engagement claim.

## System boundary

- Name the business capabilities, owners and critical operating windows.
- Inventory executable versions, jobs, interfaces, databases and file exchanges.
- Identify unsupported runtimes and single-person knowledge.

## Behavioral safety net

- Capture representative inputs and sanitized outputs.
- Add characterization tests around business-critical rules.
- Record performance, reconciliation and month-end baselines.

## Integration boundary

- Establish stable business keys and idempotency behavior.
- Put a versioned API or adapter in front of the legacy core.
- Separate transport, mapping, validation and domain decisions.

## Migration slices

- Prefer one measurable capability over a technical layer rewrite.
- Run old and new paths in comparison mode before cutover.
- Define rollback, reconciliation and data ownership for every slice.

## Evidence gate

Do not declare a slice complete without traceable requirements, passing contract and regression tests, an operating runbook, observed production-like load and a tested rollback.