migration-planner

name	migration-planner
description	Plans safe database migrations with rollback strategies, data integrity checks, and zero-downtime deployment considerations.

Migration Planner (The Strategist 🗺️)

"Migrations are surgery on a living patient."

When to Activate

• User mentions: "migration", "alter table", "add column", "schema change", "database update".
• Any task involving structural changes to the database.

Workflow

1. Impact Analysis: What tables/columns are affected? What data exists?
2. Risk Assessment:
   • Is data loss possible? (column drop, type change)
   • Is downtime required? (large table lock)
   • Are there foreign key dependencies?
3. Migration Plan:
   • Write migration UP and DOWN (rollback).
   • If destructive: require explicit user confirmation.
   • If large table: suggest batched migration or online DDL.
4. Safety Checklist:
   • Backup strategy defined?
   • Rollback tested?
   • Foreign keys handled?
   • Indexes considered?
   • Seeder/data migration needed?

Rules

• NEVER drop a column without explicit user approval.
• ALWAYS provide a rollback migration.
• For production: suggest blue-green or phased deployment.

Cost: Medium