There can be a fine line between precocious and pretentious, but the aspiring poet Max Ritvo who emerges from Sarah Ruhl’s new play “Letters From Max” barges right into the latter territory almost from the start.

Seldom has such a tedious show been borne from such noble intentions, in this case for Ruhl to honor her one-time ace student whose life was claimed at age 25 by a cancer he had been battling since his teenage years. Their correspondence over the last four years of his life was marked by a gentle literary back-and-forth, some grappling for apt metaphors for death, and a whole lot of mutual congratulation.

Like much poetry, this all plays out much better on the page, and Ruhl published their correspondence five years ago. But on stage, the dynamic between teacher and student feels forced and artificial. Jessica Hecht appears withdrawn as Ruhl, hesitant to challenge Max in any possible way as if an out-of-place comma might exacerbate his fragile physical condition. Meanwhile, Max continues to be deferential to his former professor long after he leaves her classroom, seemingly grateful that she has remained in his life at all. He’s played with a cancer-defying verve by Zane Pais, who projects an inner light and keen intellect that goes a long way to explain why Ruhl was drawn to him in the first place (Ben Edelman, who alternates in the role, appears on stage as a silent extra and occasionally adds an underscore on piano).

But a mutual admiration society is, by its nature, a self-contained bubble that has little need for outsiders. And therein lies the problem. Director Kate Whoriskey’s show, which opened Monday at Signature Theatre and runs two hours with an intermission, could use more of the distillation, and condensation, that benefits all great poetry. In fact, the snatches of poetry that we do get — particularly in the over-long first act — are often underwhelming, offering few clues of Ritvo’s hyperbolically praised gifts.