The 23-year-old midfielder was excellent last season and now gets his League Two chance.
It came after Aldershot swooped to sign Fleet’s Dean Rance on Monday.
Rovers manager Mark Cooper said: “He’s another good young prospect and the kind of box-to-box midfielder we haven’t got, that pure legs and destructiveness.
“He has quality on the ball, something we are going to work with, and he is highly thought of.
“It was only due to the fact that Ebbsfleet have got well documented issues that we’ve managed to get him for a nominal fee and a big thank you to Gary Hill there for making it run smoothly.”
Adams said on Rovers’ website: “I watched the play-offs and the team that caught my eye were Forest Green.
“The way they played their football, they looked like a good club. I never thought, at the time, I would come and join them.
“I was on international duty and I got a call saying that Forest Green were interested and I couldn’t say no, it’s a great club.
“I will give 110%, no matter what. I’m known as a box-to-box midfielder, I love defending, love attacking and love being involved in the game.
“I will give my all for the team and I’m looking forward to showing what I can do here.”