Ship it path Change safely Free module

Change one thing without breaking the rest

Add one feature to a working app and keep every older feature working.

Example brief

A household task list already works. A housemate wants a button that clears every finished task in one go. The danger is that the AI changes more than that.

An example. Use your own idea next.

Steps

Use the starting project on the right: add a task, mark one done, delete one. Write down what works.
Describe the one change and list what must stay exactly the same.
Generate, then run the behaviour tests. Do the old features still work?

What you will learn

Regression: When a change breaks something that used to work. AI edits cause them often because the model rewrites more than you asked for.
Scoped change: A request that names one change and says what must stay the same, so the AI has less room to break other things.

A sample prompt

Add a Clear completed button that removes every finished task. Keep the add form, the Done and Delete buttons and the counter exactly as they are.

Write yours first, then compare.

To complete it

Pass all 9 checks and 4 behaviour tests on one version, then accept. You start from a working project and change it.