How to write test cases someone else can run

Most test cases are written by the person who built the feature, in a hurry, for themselves. They read fine to the author and fall apart in anyone else's hands: a step that assumes you know where the button is, an expected result that says "works correctly", a check that only passes if you ran the one before it. This post is about writing them so somebody else can run them and reach the same answer you would. That matters more now than it used to, because "somebody else" is increasingly a teammate on a different phone, a client doing acceptance testing, or an AI assistant working through your