Plaid Cymru membership have voted overwhelmingly in favour of the Co-Operation Agreement with Welsh Labour in the Senedd.
There was 94% support for the deal in a vote, which followed a debate at Plaid Cymru's virtual conference.
The agreement is a joint policy programme covering 46 areas, ranging from the delivery of free school meals to all primary school pupils; a commitment to take immediate and radical action to address the second homes crisis, to long-term reform of the Senedd.
The deal has been described as a "new form of political working arrangement". The two partners –the Plaid Cymru Senedd Group and the Welsh Government– will work together to jointly develop and oversee the delivery of the policies covered by the agreement over the coming three years.
Announcing the Arrangement earlier in the week, Adam Price, Leader of Plaid Cymru said: “Almost a quarter of a century ago, people in Wales voted for self-government for Wales, with a promise of a new type of politics.
“They placed their trust in a new democracy with an instruction to work differently – inclusively and co-operatively.
“The challenges we face require real ambition to deliver radical ideas. The fallout from leaving the European Union, the legacy of the pandemic, and the UK Government’s determination to erode the Senedd’s powers all increase the need for transformational change.
“Taken together, the bold policy pledges will unite Wales and benefit every generation, from all primary school pupils receiving free school meals to a national care service, free at the point of need.
“I am pleased this pioneering Co-operation Agreement is founded on common ground on a range of issues that will make a long-lasting difference to people’s lives.”
First Minister Mark Drakeford said: “The Welsh Government has an ambitious Programme for Government, which it will deliver over this Senedd term. But we do not have a monopoly on good ideas and we will work with progressive parties where we have shared and common interests to benefit people in Wales.
“This Co-operation Agreement brings the Welsh Government and Plaid Cymru together to respond to some of the most pressing issues facing Wales today, such as climate change and the energy and cost-of-living crisis.
“We can achieve more for people in Wales by working together and the Co-operation Agreement is both a response to the external challenges we face and a chance to build on the opportunities in our future. It will also help us secure a stable Senedd over the next three years, capable of delivering radical change and reform.
“These commitments build on our shared values of social solidarity, a sustainable planet and a vibrant democracy.”