Prompt recipes

You're new to a payments service or picking up someone else's code.

Explain what [file name] does in the checkout flow. List the external calls it makes, where card data is handled, and anything that looks risky for PCI scope.

You want numbers for the pilot readout.

Look at [repo] and suggest where Copilot could shorten PR cycle time most: tests, review comments, or boilerplate. Give three concrete examples from the code.

Starting a new mobile screen.

Using our existing [Kotlin/Swift] patterns in [folder], scaffold a screen for [feature] with a view model, loading and error states, and one unit test.

Before you merge a change to payment logic.

Write unit tests for [function] covering declined cards, duplicate submissions, currency rounding, and network timeouts. Use our existing test framework and mock [payment client].

A fraud or risk rule has grown hard to read.

Refactor [function] into smaller named steps without changing behavior. Keep every existing branch, and list any case where the old and new versions could differ.

A pull request touches cardholder or customer data.

Review this diff for data handling issues: logging of sensitive fields, data sent to new services, and missing input validation. Point to exact lines.