Barcelona captain Messi is in his 16th season as a first-team player at Camp Nou, having made his LaLiga debut in October 2004.
The 32-year-old signed a fresh four-year contract in 2017 but the agreement has been revealed to include a clause which gives him the option of leaving on a free transfer at the end of each campaign.
Messi, who denied being in talks over a new deal, does not intend to leave, although his commitment comes with one key condition.
"What I can say is that I want to be at Barcelona as long as possible," Messi said in an interview with SPORT.
"I've said throughout my career that this is my home. But I also don't want to have a long-term contract and only be here because of it. I want to be here because physically I'm fine to play and be an important member of the squad.
"And as I said before, I need to see there's a winning team because I want to keep winning things at this club.
"For me, money or a clause don't mean anything. Other things motivate me and the most important thing is having a winning team."
He added: "Obviously, I want to win and I want to win at this club. This is my home. I don't have any intention of going anywhere but I want to keep competing and winning."
At the top of his wish list is a fifth Champions League crown.
Messi and Barca looked set to end a four-year European drought upon reaching the semi-finals last season, only to give up a three-goal first-leg advantage as they crumbled to defeat against Liverpool at Anfield.
Ernesto Valverde's job was called into question but star forward Messi, while adamant the club "must" win the Champions League, absolved the Blaugrana boss of blame.
"When these things happen, everyone thinks the worst because we didn’t complete our objectives," the 10-time LaLiga winner said.
"Something similar happened in the previous year too, although I believe it was worse on this occasion.
"As I said in the moment, we [the players] are to blame. The coaching staff had nothing to do with the performance we put in.
"Until that moment we had a great season, dominating the league from the first moment, making the final of the Copa del Rey.
"It was more an issue with us than with the coaching team."