Explain the Why Behind Constraints
Give the reason behind each rule. Claude applies the why to cases you never spelled out.
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.
Scaffold the Payments Collection
Lattice Pay is about to become Brightdesk's second payments provider, and Kenji Watanabe, the integrations engineer, wants to call every endpoint before he writes any code. Bea Kowalski, the QA lead, wants that as one Postman collection (a saved, shareable set of API requests)…
Set Up the First Test
tidepool has a skeleton now: `src/app.ts` builds the app with Fastify (the web framework the club chose) and `src/server.ts` starts it. The `test` script is still a placeholder. Selin and Felix, two new contributors, join in a few weeks and will copy whatever the first test…
Other principles in Constraints
Define Component Boundaries
When splitting a component, give the decisions already made and say nothing on screen should change.
Define Inputs and Outputs
Say what goes in, what comes out, and what happens with bad input. Leave the inside to Claude.
Define the Business Logic
Turn business words into exact rules: the fields, the thresholds, and how they combine.
Deprecate Before Removing
Keep the old name working for a release, point to the replacement, and announce when it goes away.
Describe Edge Cases
Name the unusual cases you know about and what should happen in each.
Describe Type Contracts
Tell Claude the rules the code doesn't show, like allowed values and optional fields. It can work out the rest.