To Be or Not To Be a Thought Partner?

A "thought partner" has no title. It's a role you can be written out of, and conversations can happen when you're not in the room. Someone floats a problem your way, watches what you do with it, and learns two things at once: whether your thinking is good, and whether you're a team player. If the ideas are strong, they get absorbed into the project with no attribution required, because "thought partner" was never a role that came with ownership.

How do you make this work for you?

Don't agree immediately. This is a negotiation. They came to you. Ask for credit, ask for a title on the project, ask for a literal seat at the table in the highest level of decision making appropriate to your abilities. Ask and you'll know exactly what this is - you'll find out fast whether the invitation was ever about your value, or about access to your ideas.

It's testing the waters because nothing was promised. And that's the point.