The agreement aims to close the rift between Saudi Arabia and the United Arab Emirates, nominal allies in a war against Yemens Iran-backed Houthi rebels.
Nizar Haitham, a spokesman for the STC, welcomed the coalitions calls for a cease-fire and de-escalation across Yemens southern governorates.
In a statement, he emphasized the urgent need to implement the Riyadh deal and thanked Saudi Arabia for its diplomatic role.
This spring, Saudi Arabia declared a unilateral cease-fire, which quickly collapsed.
The government has rapidly lost credibility, she said, leaving Saudi Arabia in an embarrassing position, caught between Hadi and the separatists even as the Houthis escalate their attacks.