Vellum Migration Checklist

When A Migration Is Required

Use a migration for shipped interfaces and persisted data:

• DB schema changes, indexes, backfills, or persisted row shape changes.
• Workspace file renames, moves, format changes, or namespace changes.
• Stored config or data that existing installs must keep reading.

Do not delete migration files. Migrations are append-only, even when their logic becomes obsolete.

DB Migrations

For DB migrations:

1. Add a new file under assistant/src/persistence/migrations/.
2. Make it idempotent and safe to retry after interruption.
3. Register it in the migrationSteps array in assistant/src/persistence/steps.ts.
4. Update schema modules if the runtime schema changed.
5. Add or update a focused db-*migration*.test.ts test.

Check for ordering drift and never reorder existing migrations.

Workspace Migrations

For workspace migrations:

1. Add a new numbered file under assistant/src/workspace/migrations/.
2. Append it to WORKSPACE_MIGRATIONS in assistant/src/workspace/migrations/registry.ts.
3. Make the migration idempotent.
4. Add or update a focused workspace-migration-*.test.ts test.

Never reuse or reorder existing migration IDs.

Release Notes Migrations

There is currently no release-note surfacing mechanism. The update-bulletin feature (workspace migrations appending to a workspace bulletin file, processed by a background conversation at daemon startup) was removed. Do not add new 0XX-release-notes-* workspace migrations — the historical set is frozen by workspace-release-notes-feature-flag-guard.test.ts. If a release needs user-facing notes, design an explicit on-demand surfacing mechanism first.

Verification

Run the focused migration test first. Add package typecheck when migration exports, schema types, or registry wiring changed:

bash
cd assistant && bun test src/__tests__/workspace-migration-example.test.ts
cd assistant && bun test src/__tests__/db-example-migrations.test.ts
cd assistant && bunx tsc --noEmit

Replace example paths with the actual test files related to the change.