Hi NicolaThe short answer to that question is "Yes."
First I'd like to thank you very much for writing the super-fab 'Write To Be Published', exactly the book I've been looking for ever since I began writing ... hmm ... pre-children, so that would be well over 16 years ago!! [...]
I've always sweated buckets when it came to synopsis-writing but after reading your book, I actually found it fun, in a perverse sort of way. [NM: Now that is perverse!] Colour me oh-so-pleased when I managed to fit the synopsis of my YA fantasy onto 2 sides of an A4, and in a coherent manner! Then I came back to earth with a bump. The first agent on my list wants the query to be the equivalent of one page in length, to include a short synopsis and a few lines about me. So, my question is, should the synopsis in this case be more like an extended version of a pitch, focusing fully on the main character, and including the ending? Probably seems silly but I'm quite nervous about the sending the 'wrong' thing and inadvertently shooting myself in the foot.
The longer answer is still yes, but includes an explanation of what's going on with this specific request. (Always allow specific guidelines from an agent to over-ride any general advice.) What this agent is asking for is something much more like a US query letter. A US query does not include a sample of the book or a longer synopsis. It has to work even harder than a normal UK submission (which usually consists of a covering letter, synopsis and sample, and may also include a CV and proposal, for certain types of book.)
So, yes, the "synopsis" that this agent is asking for is a slightly extended version of a pitch. It's not really much different from our covering letter - though you don't say whether this agent is also asking for the first three chapters as a sample.
Yes, you should indicate how the book ends; make the main character feel very compelling; make the agent understand exactly what the MC's driving force is and what the stakes will be if he fails.
When you give a few lines about yourself, do try to make this either 100% relevant to your writing career potential or incredibly interesting in some other way. If you have reasonably strong publishing credits, mention them briefly (naming publications) but don't scrape the barrel for minor or unimpressive items or list everything. Whether you're talking about the book or yourself, pick only the most important and most compelling points.
Most of that applies to all submissions and to be honest the answer to your question is simply YES!
Any comments to add from anyone else? Other insights? Anything I've forgotten?