Josh O’Connor in the movie “The Mastermind.”

(Festival de Cannes)

Leave it to Kelly Reichardt, who turned Michelle Williams into a seething sculptor with frenemy issues in “Showing Up,” to make the gentlest, most self-deprecating heist movie imaginable. As such, she’s invented a whole new genre. The year is 1970 but don’t expect anything Scorsesian to go down here. Rather, this one’s about a half-smart art thief (Josh O’Connor, leaning into loser vibes) who, after snatching canvases of a lesser-known modernist from an understaffed Massachusetts museum, suffers grievously as his plan unravels. Reichardt, herself the daughter of law enforcement, is more interested in the aftermath: hypnotically awkward kitchen conversations with disappointed family members who won’t lend him any more money and would rather he just clear out. (The exquisite period-perfect cast includes Alana Haim, Bill Camp, Hope Davis and John Magaro.) Danny Ocean types need not apply, but if you hear skittering jazz music as the soundtrack of desperation, your new favorite comedy is here. — JR