McLaren announced last week they had retained the services of the 2009 world champion after Button had indicated previously that he could call time on a 16-year career as a grand prix racer.
"I had thoughts about what direction I would take if I wasn’t here next year, what I could possibly do, but it wasn’t in my mind for very long," the Briton told reporters at the Russian Grand Prix.
"I had a really good week last week, very positive spending it with a lot of key individuals within the team, the heads of department that are really going to make a difference," added Button.
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"So I have real belief that it is going to be much better next year, both on the car and engine side, and that’s why I want to be racing here next year."
McLaren, who have won more championships than any team other than Ferrari, this year began a new partnership with Honda and have endured a nightmare on the track with just 17 points from 14 races.
The lack of performance, for a team that last won a race in 2012, had led to speculation that Button could walk away rather than endure another year of being lapped and starting at the back of the grid.
"The only reason you want to keep racing is to have a chance of being competitive, and obviously we’re not there yet, but it will be the case in the future," said Button.
"There are going to be lots of changes within the team, with the power unit. This is still a very young partnership and lots will change over the winter and we’ll be more competitive next year," he added.
Button, who is the most experienced driver on the current grid, said the sport was changing and the future looked bright.
"I don’t know if I’ll be racing in 2017 or 18, but it looks very exciting, which is something the sport and the fans should be excited about," he said.
"There’s definitely no fear of leaving F1. I’m here because I want to be here and this team is going to be competitive in the future, and that’s the reason why I want to stay."
(Reporting by Alan Baldwin, editing by Pritha Sarkar)
