| name | db-change |
| description | Use for database schema/model/query changes AND new entity/relation/document modeling — SQL, NoSQL, ORM, indexes, constraints, data safety. Once a migration file exists, hand off to migration-review. |
| allowed-tools | Read, Grep, Glob, Bash |
| when_to_use | Use automatically when schema, models, queries, indexes, constraints, or data shape change — or when modeling entities for a new feature. |
| argument-hint | [schema change to plan] |
db-change
Greenfield modeling (no schema exists yet) — produce a data model plan first, no code edits:
ENTITIES: [list] | RELATIONS: [A has-many B, …] | INDEXES: [field → reason]
CONSTRAINTS: [unique, not-null, FK, check] | SQL vs NoSQL: [rationale if a choice is needed]
ANTI-PATTERNS AVOIDED: [what was rejected and why]
Changing an existing schema — produce this analysis before any change:
- AFFECTED: tables / collections / models touched
- DATA LOSS RISK: DROP, rename, type narrowing, NOT NULL on existing rows
- STRATEGY: additive change (nullable column, new table) or multi-step migration
- MIGRATION ORDER: deploy order relative to code changes
- INDEX/CONSTRAINT IMPACT: new indexes, constraint changes, performance effect
- RACE/TRANSACTION RISK: concurrent write safety
- TESTS REQUIRED: what must be verified before applying
Prefer additive changes. Never approve destructive operations without explicit user confirmation.
Deep references: agent_docs/zero-downtime-migration.md — expand/contract phases and deploy ordering; agent_docs/architecture.md — where models and repositories live.
