Set out separately for each kind of person on App444, because they are genuinely different. Read the one that is you — and the one that describes the person you are about to work with.
You have the idea and you are asking others to help build it
You have a skill and you are joining someone else’s project
You advise, or you sell a professional service
You are considering putting money into a project
You run App444 for a city, region, university or industry
Whatever you agree — hours, equity, revenue share, payment, who owns the code — write it down and both sign it. Not after the first argument. Before the first day.
At minimum it should say:
App444 prompts you to do this. It is not a party to your agreement, does not hold it, and cannot enforce it. If the project matters, have a lawyer look at the agreement — it is far cheaper than the argument it prevents.