"I think that most boys and girls don't have a lot of opportunities to play games at home or after school, when they leave here," Brooks said. "Many of them think when there is a problem you hit, you fight, you push, you defend yourself."
"There's ... not a lot of organization," he observed. "Not a lot of good positive social interaction going on."
To help nurture that interaction, Cooper split the playground into different play spaces. Class by class, he introduced simple games for the kids to choose from, from 10-second tag to ultimate football to hula-hooping.
A set of basic rules applies to all activities: Respect the game, play fairly and respect your teammates. To quickly settle differences, students are taught the old-school hand game of rock, paper, scissors.
While many educators support Playworks' initiatives, some experts are skeptical.
"We want children to be able to have a time during the day where they can take a complete break from rules, where they can make up their own games and where they can think for themselves," said Robyn Silverman, a childhood and teen development expert. "When you have a school that is thinking about using a recess coach, my hope is that they use that coach wisely, but don't use that coach as a crutch."
Vialet insists coaching wisely is exactly what Playworks is doing.
"Our capacity is to build a structure with an eye toward the kids ultimately taking responsibility," she said. "I think that's the best hope we've got towards building an environment where kids can be at school and to use their imaginations."
Teachers at Stephens said a fifth-grader who goes by the name Rico, a good student, had posed one of the biggest challenges for teachers on the playground. Now Rico was leading the games.
"He is one of the big men on campus," Cooper said. "For him to realize that he could use positive energy and still get that same respect, I'm sure is just a relief for him and you could see his eyes just glow."
Rico himself offered a rave review.
"Coach Coop makes everything organized now," Rico said. "When I wake up, I'm thinking, I don't want to go to school, but I'm thinking Coach Coop is at school. Since Coach Coop came and started everything, nobody has gotten into trouble. We all respect him very much."
During Cooper's week-long stint at Stephens, there were no suspensions on the playground and kids genuinely seemed engaged.
"We're like WD-40 for enhancing school climate," said Vialet. "We come in, we make things go a little easier, and it makes it that much easier for teachers to be really good at their jobs."
"I have to hold back my tears with that young man," Cooper said of Rico. "You know, I witness young kids get devoured by these streets every day."
Cooper said the most difficult part of his job is saying goodbye.
"The toughest part of my job by far is coming in here and building relationships, real, genuine relationships with these kids, and then having to disappear," he said. "But the beautiful thing is we're leaving all these tools and games and experiences that they can hold onto and just keep evolving."