Kelly Macdonald (last blogged for Goodbye Christopher Robin) adopts a vaguely New York accent to play Connecticut resident Agnes (Jack didn't buy her accent at all) with subtlety and grace. Irrfan Khan (most recently in Jurassic World) is delightful as Robert, the jaded millionaire in the spectacular Manhattan digs who appreciates Agnes' skill. Agnes' mechanic husband Louie, who does not appreciate her, is played with range by David Denman (best known to me for 31 episodes of The Office and eleven of Parenthood, as well as small parts in Men, Women & Children and Logan Lucky). Their sons Ziggy (Bubba Weiler, who is new to me) and Gabe (Austin Abrams, who co-starred in Brad's Status), are more sensitive than their dad, especially Ziggy.
This is the second time directing for Marc Turtletaub (he produced Everything Is Illuminated (2005), Little Miss Sunshine (2006), Sherrybaby (2006), Sunshine Cleaning, Jack Goes Boating, Safety Not Guaranteed, Loving, and more--I didn't see his other directing gig). Oren Moverman (last blogged for The Dinner) and Polly Mann (her debut) adapted the script from a 2009 Argentinian movie called Rompecabezas (it means puzzle in Spanish) written and directed by Natalia Smirnoff. One spoiler-prone Village Voice reviewer wondered how Agnes can be so sheltered. I didn't, really. It's just the style of the story, and probably comes from the source material.