Is it a “gentleman’s agreement”?
Yep. Was talked about earlier in the summer, the details given and the source made it more than believable to me then, and it explains why Chelsea - and City - didn't pursue things.
As regard whether it's a real agreement, Mino and Perez would be unlikely to fuck about with each other, could cost either big time in the future.
However, I get the feeling the agreement is going to be ripped up by mutual agreement, with Real taking Mbappe and Haaland opting for Bayern. Hence Lewa's announcement today. He's got wind, for sure.
There's always a risk these agreements are broken, but it usually ends a relationship for good (unless, like Real and Mino, both are OK with ripping up the agreement). And the party breaking it will not be trusted in the future.
Take a Spurs player now, say, Son. He gets offers elsewhere, Barca is his dream and they offer him a contract. Levy says, ok, sign again now, you can go next year, you have my word.
If Levy forced Kane to stay this year, would Son's agent trust him? No. Not a chance. No agent would. It would hurt Levy's ability to convince players to join and extend contracts for a long time.