Look for a repeated handoff
Maybe you paste release links into the same format every Friday. Maybe you rename exported images before every upload. Write down the current steps, including the annoying exceptions. A useful first tool removes one mechanical step while leaving the decisions with you. Save a real example of the input and the exact output you would accept.
Make the boundary visible
Specify how the tool receives data, where the result goes, and what happens when input is empty. Start with a local file or pasted text. Add accounts, storage, or background processing only when the original task actually needs them. Ask your coding assistant to explain the smallest implementation and identify any dependency it wants to introduce.
Pick a finish line
Try one ordinary example, one empty example, and one awkward example. A finished utility should give a useful error instead of quietly changing data. Keep the original input available until you have checked the result. The next feature belongs on a separate list; completing this single workflow is enough for version one.