void-service-package

Create a directory under packages/ with package.json, tsconfig.json extending tsconfig.strict.json, and a src/ folder containing five source files (service, repository, helper, types, index) each paired with a test file. Write the Zod-based types first, then TDD the service, and run turbo typecheck and test before committing.

The 5+5 layout is five source files paired one-to-one with five test files: <name>.service.ts, <name>.repository.ts, <name>.helper.ts, <name>.types.ts, and index.ts, each with a matching .test.ts. No utils/, lib/, or common/ directories are allowed; each file does one thing.

The concrete adapter lives in the consuming app under apps/<app>/src/adapters/<name>/, not in the shared package. The package's repository.ts defines only the port interface plus an optional in-memory implementation for tests, and the app wires the production adapter.

No, a service package may only import @repo/core for the logger, env, errors, and Result/Option/pipe utilities. If another @repo/* import seems necessary, either move the shared concept into @repo/core or reshape the boundary so the consumer composes both packages.

Do not create a package if you cannot state in one line what it owns, exposes, and who consumes it, or if the code is internal to a single app under apps/<app>/. A sixth source file that fits nowhere signals the boundary is wrong and the package should be split or reshaped instead.