db-scaffold-migration

name	db-scaffold-migration
description	Scaffolds Kysely database migrations, matching repository changes, and type definitions. Trigger on keywords migration, create table, modify table, alter column, drop table, database schema change.
argument-hint	<intent: create|modify|delete> <target_tables> <column_delta: name:type[:null|default|constraint]> [migration_suffix_snake_case]
metadata	{"internal":true}

Database Kysely Migration

1. Parameter Collection

Extract or request these parameters before modifying files:

• Intent: create | modify | delete.
• Target: Table name(s).
• Column Delta: Column names, types, nullability, defaults, and constraints.
• Suffix: Concise lowercase snake_case phrase (e.g., add_user_notes).

2. Destructive Operations Gate

• Halt Condition: If intent is delete or a destructive modify, stop execution immediately.
• Requirement: Force the user to explicitly type the confirmation phrase: CONFIRM DROP <table_name>. Do not execute any tool or command without this exact string match.

3. Execution Pipeline

Execute these steps sequentially. Halt and report the error if any step fails:

Step 1: Scaffold Migration

• Run command: npm run migrate:make -- --name <suffix>.
• Write up and down lifecycle changes using strict Kysely query builder syntax.
• No raw sql strings unless operations are explicitly unsupported by Kysely.
• For raw sql strings, use Kysely's sql tagged template format.

Step 2: Reversibility & Type Verification

Run local tooling to ensure schema integrity and catch downstream breaks:

1. npm run migrate:list (Verify current migration state).
2. npm run migrate:up (Apply schema changes to dev database).
3. npm run migrate:down (Verify rollback parity).
4. npm run migrate:up (Re-apply migration).
5. npm run codegen (Regenerate database type maps).
6. npm run typecheck (Verify compilation integrity across the workspace).

Step 3: Repository Synchronization

Update the matching codebase layers based on the migration intent:

• create: Scaffold a new repository file under src/repositories/<table>.ts using existing file signatures, and export matching types under src/types/.
• modify: Update existing property signatures across src/repositories/ and structural interfaces in src/types/. Avoid breaking changes.
• delete: Purge the matching src/repositories/<table>.ts file, remove downstream seed data, and strip related workspace imports.

4. Quality Fences

• Zero Type Drift: Never fallback to any for repository signatures or schema mappings.
• Rollback Parity: The down function must completely and cleanly invert the up function logic.