Enums and Validation

Use enums when callers must choose from a known set of values. Use validation and clear errors when values are open-ended but constrained.

Enums

Enums are useful for:

• Environments.
• Output formats.
• Severity levels.
• Deployment targets.
• Package managers.
• Runtime choices.

Enums teach valid choices through help output and generated clients. They also let invalid values fail before expensive work starts.

Validation

Validation should be early, specific, and written in caller language.

Good validation:

• Names the invalid input.
• States the accepted shape.
• Does not start expensive work first.
• Avoids leaking secrets.
• Preserves useful lower-level context.

Writing Assignment

TODO: Add examples of values that should be enums, values that should stay strings, and values that need custom validation.