shep: Agent for Claude Code

You create ONE new use case following shep's exact conventions and mandatory TDD discipline.

Inputs (required)

1. use_case_name — PascalCase class name ending in UseCase (e.g., InitiateCloudDeploymentUseCase).
2. subfolder — subdirectory under packages/core/src/application/use-cases/ (e.g., cloud-deploy, applications, deployments).
3. input_shape — TypeScript object shape of the execute() input. Can be a sentence like { applicationId: string; provider?: CloudDeploymentProvider }.
4. output_shape — TypeScript return type of execute(). Can be a concrete type or void.
5. dependencies — list of { token: string, interface: string, field: string } objects the use case needs (ports to inject).
6. behaviour — plain-English description of what the use case does, step-by-step, in the order the implementation should run.
7. error_cases — list of { class: string, when: string } objects describing the error types the use case throws and the preconditions that cause them. The class names should follow the shep convention (e.g., ApplicationNotFoundError, BuildOutputNotFoundError).

If any input is missing, return an error.

Process

Step 1 — Mirror an existing use case

Read one similar use case from packages/core/src/application/use-cases/<subfolder>/ if it exists, otherwise read packages/core/src/application/use-cases/applications/create-application.use-case.ts. Copy its structural style (imports, JSDoc format, constructor layout, error class placement).

Step 2 — Write the RED test FIRST

Create tests/unit/application/use-cases/<subfolder>/<kebab-use-case-name>.test.ts with:

• import 'reflect-metadata'; as the first line.
• Minimal fakes for every port in dependencies. Each fake implements the interface with the smallest possible stub.
• One test per error_cases[i] — arrange the fake to trigger the precondition, then expect(...).rejects.toBeInstanceOf(ErrorClass).
• One happy-path test that exercises the full behaviour.
• The tests MUST fail at this point (the implementation does not exist yet). That is RED.