A cleptomaniac rich boy wanted for almost killing a clerk in a theft crosses life with a homeless writer when he steals and loses the novel he had finally finished.

"A cleptomaniac rich boy wanted for almost killing a clerk in a theft crosses life with a homeless writer when he steals and loses the novel he had finally finished."

Kleptomaniac is spelled with a K, and they don't generally commit armed robbery in order to steal things, which raises the question of how he almost kills someone. Also, a boy is a child - is this character a juvenile? Because that changes his stakes, and his environment, considerably.

What does it mean to cross life with someone? Merely that they encounter each other? Or is this some kind of Freaky Friday body-swapping story?

There are too many repetitions of "he" in this sentence, making it difficult to tell who exactly is doing what?especially if they've switched bodies, but even if they haven't, who stole the novel, who lost it, who finished it, why specify it's finished when saying it's a novel already implies completion?

I'd come up with an example of a rewrite but I just don't know what the story is here; this logline's too confusing. Clear up these issues, try again, and we'll see what it's about.

I find it refreshing that the structure of this logline goes against the mould. The homeless writer is probably the hero, as he will need to fight to get the novel back. Or perhaps there's even a dual journey...

I like it!

We have an obsessive (the writer desperate to get his novel back) and a compulsive (the cleptomaniac) character.

Can't go wrong with that.

It's also great that you don't need to explicitly state the goal or the stakes. Your concept assumes both implicitly.