Describe Expected Behavior

Where you'll practice this

2 Promptles scenarios teach this principle directly. Each one drops you into a real engineering ticket and asks you to write the prompt you'd send to Claude Code.

• Test the Validator

  You have a function `validateEmail` in `validation.js` that checks if a string is a valid email address. It returns `true` for valid emails and `false` for invalid ones. You want Claude Code to write unit tests for it using Jest.

• The Test Suite

  You're writing Postman tests for `GET /api/users/:id` on your internal user service. A successful response is `200 OK` with a JSON body containing `id` (UUID string), `email` (string, RFC 5322), `displayName` (non-empty string), `createdAt` (ISO 8601 timestamp), and `role` (one…

Other principles in Clarity

• Be Specific

• Describe the Visual Target

• Describe What, Not How

  Tell Claude what the function should do, not how to write it.

• Invoke the Right Skill

  Match your task to an existing skill or slash command and call it by name.

• Master the Art

• Name the Services

  Name the service, the version, and the endpoint.