I am currently working on a few high profile projects which are highly interesting for the company. I am observing lots of interest from my colleagues, and as projects start getting steam and first results come in there is more and more people who want to be in the loop, participate in meetings and contribute.
I can see at least two types of self-invited contributors:
peers: other developers or commercial staff, who have a minimum technical background and want to contribute a little to put their name on the project. In the most extreme case, these people expect me to develop software which will let them get some fancy tables to present as their own contribution;
managers: in the best case they recognise the benefit and they want to be involved, in the worst case they add themselves to the project to create more "discussions" contributing nothing but delaying things.
In both cases my work is delayed in exchange for almost no contribution, and my own boss is already aligning this project with the company's interests.
My question is: how can I defend myself from all these self-invited contributors, in a professional way which will protect my best interests without damaging my career?