Breaking Change Migration AI Prompt

Design a safe migration process for this breaking schema change.

Breaking change: {{change_description}} (e.g. renaming column customer_id to account_id, or changing the grain from order to order_line)
Affected table: {{table_name}}
Known consumers: {{consumer_list}}

1. Impact assessment:
   - Query the data lineage graph to find ALL consumers of the affected table and column
   - For each consumer: team, table/report name, how the breaking column is used, migration effort (Low/Medium/High)
   - Identify any external consumers (APIs, applications) that cannot be migrated centrally

2. Migration strategy: Expand and Contract (strangler fig pattern):
   Phase 1 — Expand (add, don't remove):
   - Add the new column/structure alongside the existing one
   - Populate both: old column = old value, new column = new value
   - Publish schema with both old and new columns
   - Notify all consumers: 'New column available, please migrate. Old column will be removed on {{sunset_date}}'

   Phase 2 — Migrate:
   - Support consumer teams in migrating their pipelines/reports to the new column
   - Track migration progress per consumer team
   - Provide a migration deadline: {{deadline}}

   Phase 3 — Contract (remove the old):
   - Verify all consumers have migrated (query lineage + direct confirmation)
   - Remove the old column
   - Publish final schema version

3. Rollback plan:
   - At each phase: what is the rollback procedure if a critical consumer cannot migrate in time?
   - Rollback requires reverting only Phase 1 changes — no data is lost

4. Communication plan:
   - Initial announcement: {{notice_period}} before Phase 1
   - Weekly migration status updates to all consumers
   - Final warning: 1 week before Phase 3

Return: impact assessment table, phase-by-phase implementation plan, consumer communication templates, and rollback procedure.