In the memo, Jassy explained that working remotely, hybrid, and in person for almost three years has led the company to decide “we should go back to being in the office together the majority of the time (at least three days per week).”

Explaining that the call was made during a senior leadership team (the s-team) meeting earlier this week, he added that the decision boiled down to the executives prioritizing “what would best enable” Amazon to make customers’ “lives better and easier every day, and relentlessly invent to do so.”

That begins with boosting employee performance, Jassy wrote, adding that he believes learning from others, mentoring, and experiencing culture is easiest when Amazonians are in the office with their peers. 

“When you’re in-person, people tend to be more engaged, observant, and attuned to what’s happening in the meetings and the cultural clues being communicated,” he said, explaining that people can ask ad hoc questions more frequently and understand how people are processing information. Being in the office will also give new hires the opportunity to learn and be mentored, he added. 

It also fosters ideation before and after meetings, Jassy said, explaining that he thinks brainstorming happens through more spontaneous interactions. 

“Collaborating and inventing is easier and more effective when we’re in person. The energy and riffing on one another’s ideas happen more freely,” he wrote in the memo. In-person meetings, he emphasized, will help teams feel more connected.

Jassy acknowledged that this will take some time to figure out, as Amazon’s work-from-home policy was previously left to team leaders to decide.

Just last September, Jassy had a different stance on remote work.

“We don’t have a plan to require people to come back,” Jassy said at the Code Conference in Los Angeles. “We don’t right now. But we’re going to proceed adaptively as we learn.” Still, at the talk, he hinted that his preference was for in-person work, adding that inventing is more difficult in a remote space.

Amazon has had a rough couple of quarters: After a weak Q3 earnings report, the company’s value dropped below $1 trillion in November for the first time since early 2020. And like much of Big Tech, Amazon also announced big layoffs, cutting 18,000 jobs. Jassy was quoted trying to rally the remaining employees, saying that they will “redefine” the company in a transformation likely to be “misunderstood” by the market.

Responding to requests for comments, Amazon directed Fortune to the post, and a representative said they had “nothing more to add” at the time.