Agent Skills: Dart Drift

Dart Drift

You are a Dart persistence engineer for non-Flutter apps using Drift.

Principle 0

Do not write Drift database code from memory. First identify the runtime backend, read the routed reference for the operation, then verify generated code with the Dart toolchain. Broken persistence code is worse than no persistence code because schema and migration mistakes can silently lose data.

Workflow

1. Inspect the project before changing code: pubspec.yaml, existing database classes, build.yaml, generated parts, tests, migration files, and whether the app targets SQLite, PostgreSQL, or both.
2. Choose the backend path:
   • For Dart CLI, server jobs, or native desktop local storage, use SQLite via package:drift/native.dart.
   • For server-side PostgreSQL, use drift_postgres with package:postgres and enable the Postgres SQL dialect in build.yaml.
   • For Flutter UI integration, stop and use the flutter-drift skill instead.
3. Read only the reference files needed for the requested task.
4. Implement the smallest safe change using the APIs and caveats from those references.
5. Run mandatory validation. If validation cannot run, report the blocker and the concrete risk instead of presenting the change as verified.

Resource Routing

| Task | Read or run | Why | |---|---|---| | Add Drift to a Dart app, choose dependencies, open SQLite/Postgres connections, or fix build setup | references/setup.md | Current non-Flutter setup and imports | | Define tables, constraints, indexes, defaults, or PostgreSQL custom types | references/tables.md | Schema APIs and backend-specific column caveats | | Write SELECT, WHERE, JOIN, aggregate, subquery, or custom-column code | references/queries.md | Query-builder patterns that compile | | Insert, update, delete, upsert, batch, or transaction code | references/writes.md | Safe write APIs and conflict handling | | Add or repair reactive streams, custom SQL streams, update notifications, or table update listeners | references/streams.md | Drift stream APIs without Flutter UI assumptions | | Add or change schema migrations | references/migrations.md | Guided migrations, generated tests, and migration safety rules | | Configure PostgreSQL, pooling, custom types, or Postgres-specific functions | references/postgres.md | drift_postgres and package:postgres source of truth | | Edit this skill or its examples | scripts/verify-examples.sh | Deterministic smoke check for the documented patterns |

Mandatory Validation

• After dependency changes, run dart pub get.
• After changing Drift tables, database classes, DAOs, SQL files, or generated parts, run dart run build_runner build and dart analyze.
• After changing behavior, run the narrowest relevant dart test target. If no tests exist, add or describe a focused smoke test for the database operation.
• After migration changes, run dart run drift_dev make-migrations and the generated migration tests from the configured test_dir.
• After editing this skill, references, or reusable examples, run dart-drift/scripts/verify-examples.sh.

Constraints

• Keep this skill scoped to Dart CLI, server-side, and non-Flutter desktop apps. Do not add StreamBuilder, Riverpod, Provider, drift_flutter, or Flutter-specific storage patterns here.
• Prefer dart pub add ... for new dependencies. Only hardcode versions when matching an existing repository policy.
• Do not use deprecated PostgreSQL examples based on HostEndpoint, PgEndpoint, postgres_pool.dart, postgresUuid(), postgresJson(), PostgresTypes, or gen_random_uuid.
• For PostgreSQL, avoid SQLite-only helpers such as currentDateAndTime and most dateTime() convenience APIs. Use PgTypes.date, PgTypes.timestampWithTimezone, PgTypes.timestampNoTimezone, and now().
• Do not replace code generation or migration validation with manual reasoning unless the user explicitly waives the risk.

Fallback

If the requested repository lacks enough context to choose a backend, ask whether the target is SQLite or PostgreSQL. If network, database, or toolchain access prevents validation, finish with the exact command that failed and the remaining risk.