MoSCoW method
Feature creep is a real thing.  It’s pretty hard to present any technology proposal
to a group of engaged engineers without large “blue sky” converstations starting.
The MoSCoW method gives you four one word classifications that will make your intentions clear.
MUST- we will build this nowSHOULD- not committed toCOULD- not planning on itWON'T- not doing
The wiki page is so good that I’m just going to link to the MoSCoW method.