James, 43, steps into the role following Jones’ accidental collision in a live session that resulted in damage to both knees and required surgery.
The setback came on the eve of Wales’ campaign and has sidelined the 47-year-old for the rest of the tournament, which began with a 48-7 loss to England.
For Tandy, the appointment is about familiarity and swift action.
Preparing his side for defending champions France in Cardiff on Sunday, the head coach underlined why James was the right fit at short notice.
“It’s great to add Paul to the coaching team and my thanks to the Ospreys for enabling this opportunity at short notice,” he said.
“We’re all extremely disappointed for Duncan with his injury. He’s been a huge part of the environment and I want to thank him for all that he’s put into the campaign so far.
“He will be really missed around the group and we wish him all the best with his recovery.”
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James brings continuity as well as pedigree.
A former international prop with 66 caps, he has been part of the Ospreys’ coaching set-up since December 2018 and previously led scrum and set-piece work for Wales Under-20s in 2021.
His immediate brief is to guide the pack for the remainder of the Six Nations, slotting into a staff already featuring permanent assistants Matt Sherratt and Danny Wilson, alongside the returning Dragons duo Dan Lydiate and Rhys Patchell, who assisted with defence and kicking during the autumn.
The new scrum coach is eager to make an impact.
“I’m excited for the opportunity to come in and coach with Wales. I’m looking forward to doing all I can to help the boys,” James said.
Jones, meanwhile, has been forced to watch from the sidelines after his season-ending injury.
Reflecting on his situation, he said: “I'm absolutely gutted a freak injury means I'm unable to continue in camp with Wales this Six Nations.
“I've enjoyed the opportunity to coach international rugby and being able to work with this great group of players and staff.”
