A league source confirmed the report to ESPN The Magazine's Ric Bucher.
The people spoke to the AP on condition of anonymity Tuesday because the deal was yet to be finalized or formally announced by Golden State. The Bay Area News Group first reported the pending signing of Robinson, who will join a small backcourt also featuring Monta Ellis and Stephen Curry.
The Warriors are 2-3 under new coach Mark Jackson heading into Wednesday's game at San Antonio.
Thunder general manager Sam Presti announced Robinson's release Dec. 24.
A midseason acquisition last season from the Celtics, Robinson appeared in four games for the Thunder. He averaged 3.3 points and 1.5 assists in 7.5 minutes per game.
Information from The Associated Press was used in this report.