When an agent says they want a brief synopsis, what does that mean? I know you can't read the minds of other agents but would you assumethat means one page? two pages? six pages?
We really do love to torment you writers with our vagaries don't we?
My best guess, based solely on my ability to read minds of course, is that brief means one page. 250 words. 1" margins. 12 point font. In other words, don't cram 500 words on to one page with formatting shenanigans.
Brief means you're going to answer these questions:
Who is the main character?
What does he want?
Who/what is preventing him from getting it?
How does he prevail?
What does he lose/gain by prevailing?
Notice I've left out secondary characters, themes, sub-plots, backstory, prolouges, world building, and all the other things that will make your novel gorgeous, brilliant and enticing. A synopsis' job isn't to show any of those things. A synopsis is written to show me that you've got a complete plot, and that (in the words of the inimitable Lucienne Diver) "aliens don't arrive in Chapter 14."
If you've got more room (ie two pages) you can add sub plots and a secondary character.
If you can't write a 250 word synopsis to your book, you haven't learned how to revise well enough. Synopsis writing is largely a matter of spewing everything on to the page, and then taking things out, and then making every word count.
Example: Harry Potter is a 13 year old boy whose parents were killed and now lives with his wretched cousins. (19 words)
Revised: Harry Potter is a
we don't need to know his age in the synopsis. "Boy" conveys that he's not an adult.
Revised 2: After his parents were killed, Harry Potter
Moving things around in a sentence can help. Don't worry about style here, the novel is where your style shows.
Revised 3: His parents were killed so Harry Potter was sent to live with his wretched cousins. (15 words)
Sometimes you go in the wrong direction. This is when you really get down to "do you need this"
Remember, no backstory, no world building? This is where you revise that out of the synopsis.
Revised 5: Harry Potter lives with his wretched cousins. (7 words)
19 words down to 7 but it took five revisions, one of which was going backward in word count.
Now, this example is probably not how I'd start with a synopsis of any of the Harry Potter books, I used it because most of us are familiar with the story.
Revising is a learned art. If you hate it, you're not doing it right. Revising is what makes your writing shine. Revising is what makes your voice clear. Revising is what makes you a writer.
**please notice I managed to go the entire blog post without mentioning underpants, which is one of my all time favorite words (Yes I am eight years old).