The question is in the title: If I was to use the API to make a request for downloading the results of a query would that be a breach of this line in the ToS?
- You will not use any automated process to retrieve or index any portion of the site or site contents, with the exception of public search engines.

And if so, is it possible to apply for a exception? I'm assuming it is a breach and didn't want to be a dick and just start parsing things willy nilly.

Lozer has already allowed small batch downloading of our site content for end users. Just don't go crazy with it.

The main thing we wanted to stop were other servers scraping our site for profit or killing our bandwidth. Only public search engines are allowed to do that.

I don't speak for the site, but I consider that it would be fine only if you play fair and take care not to lag the site for everybody. This means requesting, say, only one image per a respectable amount of 2 seconds or something.

This was discussed a relatively short time ago in this thread and it was decided that downloaders are OK but "don't overdo it (jedi1357)"
gelbooru.com/index.php?page=forum&s=view&id=4163

Just don't make multi-threaded HTTP requests with no delay that would download thousands of images in under a minute. Use your common sense and imagine what you would allow if you were a webmaster and just do that.

We are actually pretty strong in this regard. He could max it at 15 simultaneous downloads and have 100 posts per request and this site wouldn't even flinch. Any more than that and I'm not sure.

Sweet my dude! I'm doing any mutli-threading as fo yet, but I was planning something of maybe 4-5 concurrent just to make sure everyone stayed sane. Thanks for the reply!