Sanders and his supporters have complained for months that the Democratic Party was tilted against his insurgent bid and are worried that should he lose to Hillary Clinton -- as he is expected to do -- the issues that have animated his bid will not find a place at July's Democratic National Convention.
The agreement struck by both campaigns this month looks to ensure that doesn't happen. Sanders' five slots include several bold face names in progressive politics, including Rep. Keith Ellison of Minnesota and environmental activist Bill McKibben.
Clinton will appoint six members to the powerful platform committee, according to the agreement. Rep. Debbie Wasserman Schultz of Florida, the chairwoman of the Democratic Party, will name four members.
The agreement is unusual, in part because DNC rules allow the chair of the party to pick every member of the platform committee, a group that will hammer out, write and present the Democratic Party's platform at this year's convention.
Sanders responded to the announcement Monday in a statement.
"We believe that we will have the representation on the platform drafting committee to create a Democratic platform that reflects the views of millions of our supporters who want the party to address the needs of working families in this country and not just Wall Street, the drug companies, the fossil fuel industry and other powerful special interests," Sanders said.
Clinton's campaign said they were pleased with the decision as well.
"We're pleased that the upcoming Democratic Convention will ensure supporters of Senator Sanders are well represented in the drafting of the party's platform," Clinton campaign spokesman Brian Fallon said. "The Democratic Party historically has been a big tent, representing a diverse coalition, and Hillary Clinton is committed to continue welcoming different perspectives and ideas."
Sanders has grown more contentious with Democratic Party officials as the primary season has dragged on. After losing the Kentucky primary last week, Sanders blasted the Democratic Party as a body that currently has "limited participation and limited energy."
"I say to the leadership of the Democratic Party: Open the doors, let the people in," he said at a large rally in California.
Sanders also announced this weekend that he is endorsing Tim Canova
, the congressional candidate challenging Schultz in Florida. Sanders sent a fundraising for the congressional hopeful on Saturday and the Canova campaign announced Monday that the email raised $250,000.