“Are you British? Are you knight-ed? If not, shut up.”

Diane, the barracuda of an agent looming over Douglas Carter Beane’s intermittently insightful Hollywood comedy “The Little Dog Laughed,” has plenty of career advice for her risingstar client, and that’s pretty much the only tidbit that can be published in a daily newspaper. Vulgarity, guile, and absolute insincerity are clearly prerequisites to making it in Tinseltown, but Mr. Beane suggests one deal-breaker, at least among male stars – being gay.

As a man who wrote a screenplay about three drag queens, only to see it cast with Patrick Swayze, Wesley Snipes,and John Leguizamo,Mr.Beane has plenty to say about the rigid rules of masculinity and sexuality among Hollywood’s golden boys. Neither he nor director Scott Ellis succeeds in meshing this theme with the tepid love story at the play’s center, but they regroup in time for a bravura ending as Diane (the heaven-sent Julie White) offers a scandalously simple answer to everyone’s prayers.

“One of those borderline aging pretty boys,” as he’s described, Mitchell Green (Neal Huff) isn’t a Hollywood megastar, but he’ll get there soon if Diane has her way. She covets the rights to a gay play that could launch Mitch into Hollywood’s upper stratosphere, but there’s a catch. Despite thinking of himself as “not a sex-with-guys kind of person,” Mitchell finds himself drawn to Alex (Johnny Galecki), a hustler with a heart of gold who threatens to lure Mitch away from the fast track and toward personal satisfaction. And before you can say “I wish I knew how to quit ya,” Diane shifts her attentions from sealing the movie deal to shoving our hero back into the closet.

For all of Mr. Beane’s well-documented frustration with Hollywood – his 1997 off-Broadway hit “As Bees in Honey Drown” has been in development limbo virtually since the night it opened – his depiction of the industry can be awfully naive. For one thing, we’re asked to believe that an adaptation of a gay off-Broadway play would be Mitch’s ticket to stardom. Indie prestige? Sure. But as Peter Sarsgaard (“The Dying Gaul”) or Steven Weber (“Jeffrey”) would likely tell you, that’s not really where the money is.

In fact, the “insider” intrigues of Act I could have been written by anyone with a few chapters of William Goldman and a few viewings of “The Player” under his or her belt. Or, more to the point, an episode or two of HBO’s “Entourage,” which has made an art of showing a himbo buffeted by the edicts of a conniving agent.

As in that show, the villain gets all the best material: Ms. White, who has made a career out of playing wounded birds (“Dinner With Friends,” “Fiction,” “Bad Dates”), makes her Diane a thing of grotesque wonder. She shares with fellow off-Broadway stalwart Kristine Nielsen a gift for ratcheting her physicality and emotions from 1 to 10 and back again, but Ms. White provides just the slightest hint of a wounded, resentful psyche armored with Diane’s gutter-mouthed brio and take-no-prisoners intelligence.

At the end, Diane actually becomes a sort of Mephistophelian dea ex machina,restoring order to each character’s troubles with remarkable symmetry. Mr. Beane’s real gift is to make this finale as emotionally complicated as it is structurally airtight: Mitch, Alex, and his long-suffering girlfriend Ellen (Zoe Lister-Jones) each need to make enormous moral sacrifices to re alize their self-proclaimed dreams.

The ending goes a long way toward excusing Mr. Beane’s earlier gaffes, but not all the way. His clearly autobiographical conception of the playwright in question, referred to throughout as “He Meaning Him,” is too clever by half, transforming the unseen character into both a lone voice of integrity and a neurotic mess. (One of Ms. White’s many superb comic moments comes when He Meaning Him suggests that Mitch appear in – shudder – the play instead of the film.)

Far too much of the Mitch-Alex romance covers predictable ground, and even worse is Mr. Beane’s seeming indifference to Ellen. She exists purely for plot-furthering reasons – playing a pivotal role in Act II’s central complication as well as its resolution – and Ms. Lister-Jones never has a chance with her tired quips. (“Save me from the remains of what was no doubt once a decent club.”) Messrs. Huff and Galecki are more successful at navigating the ceaselessly clever banter, particularly as Mr. Ellis coaxes the action into a near-screwball tempo, even if neither actor wears the role of lust object particularly comfortably.

During that impressive finale, Diane enumerates each character’s wishes and hopes, with an especially brutal gloss on her client. “Mitch’s dream is to be everyone else’s dreams,” she explains. “And the thing about dreams is, is that dreams aren’t always healthy, but nevertheless everyone has them.” Mr. Beane clearly includes he – meaning himself among that starry-eyed crowd, and he has written Ms.White a theatrical dream come true. Still, one wishes that he had woken up, rubbed the sleep out of his eyes, risen above the bemused generalities of “The Little Dog Laughed” and provided the unsparing insight he is so well suited to deliver.

Until January 29 (307 W. 43rd Street, between Eighth and Ninth Avenues, 212-246-4422).