migration-architect

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---
name: "migration-architect"
description: "Zero-downtime migration planning, compatibility validation, and rollback strategy generation. Tools for system, database, and infrastructure migrations with minimal business impact. Use when planning a database migration, infrastructure cutover, system replacement, or any high-risk transition that needs explicit rollback paths."
---

# Migration Architect

**Tier:** POWERFUL  
**Category:** Engineering - Migration Strategy  
**Purpose:** Zero-downtime migration planning, compatibility validation, and rollback strategy generation

## Overview

The Migration Architect skill provides comprehensive tools and methodologies for planning, executing, and validating complex system migrations with minimal business impact. This skill combines proven migration patterns with automated planning tools to ensure successful transitions between systems, databases, and infrastructure.

## Core Capabilities

### 1. Migration Strategy Planning
- **Phased Migration Planning:** Break complex migrations into manageable phases with clear validation gates
- **Risk Assessment:** Identify potential failure points and mitigation strategies before execution
- **Timeline Estimation:** Generate realistic timelines based on migration complexity and resource constraints
- **Stakeholder Communication:** Create communication templates and progress dashboards

### 2. Compatibility Analysis
- **Schema Evolution:** Analyze database schema changes for backward compatibility issues
- **API Versioning:** Detect breaking changes in REST/GraphQL APIs and microservice interfaces
- **Data Type Validation:** Identify data format mismatches and conversion requirements
- **Constraint Analysis:** Validate referential integrity and business rule changes

### 3. Rollback Strategy Generation
- **Automated Rollback Plans:** Generate comprehensive rollback procedures for each migration phase
- **Data Recovery Scripts:** Create point-in-time data restoration procedures
- **Service Rollback:** Plan service version rollbacks with traffic management
- **Validation Checkpoints:** Define success criteria and rollback triggers

## Quick Start — plan → check compatibility → generate rollback

All paths relative to this skill folder; sample inputs in `assets/`, expected shapes in `expected_outputs/`.

```bash
# 1. Generate the migration plan from a spec (copy assets/sample_database_migration.json)
python3 scripts/migration_planner.py --input migration_spec.json --format json -o migration_plan.json

# 2. Check schema/API compatibility — exits non-zero unless fully compatible (CI gate)
python3 scripts/compatibility_checker.py --before assets/database_schema_before.json --after assets/database_schema_after.json --type database --format json -o compatibility.json

# 3. Generate the rollback runbook from the plan
python3 scripts/rollback_generator.py --input migration_plan.json --format both -o rollback_runbook
```

Outputs chain: `migration_plan.json` (`phases`, `risks`, `estimated_duration_hours`) feeds step 3; `compatibility.json` reports `overall_compatibility` plus `breaking_changes_count` / `potentially_breaking_count`.

**Gate:** the migration is not approved until (a) `compatibility_checker` exits 0 (`overall_compatibility: compatible`) or every breaking/potentially-breaking item is explicitly accepted by the owner in writing, and (b) a rollback runbook exists for every phase in the plan. Re-run both checks after any schema revision.

## Migration Patterns

### Database Migrations

#### Schema Evolution Patterns
1. **Expand-Contract Pattern**
   - **Expand:** Add new columns/tables alongside existing schema
   - **Dual Write:** Application writes to both old and new schema
   - **Migration:** Backfill historical data to new schema
   - **Contract:** Remove old columns/tables after validation

2. **Parallel Schema Pattern**
   - Run new schema in parallel with existing schema
   - Use feature flags to route traffic between schemas
   - Valida