What is a motion for particulars and when would I bring one in Ontario?

A motion for particulars asks the court to order the other side to provide more specific detail about allegations in their pleading before you have to respond to them. Ontario's pleading rules require a party to plead material facts, not just broad conclusions, but pleadings sometimes arrive vague enough that it's genuinely unclear what case you're being asked to meet — for instance, a claim alleging "fraud" or "negligence" without saying what was actually done, when, or by whom. Before bringing the motion, the usual practice is to request the missing detail directly in a letter; the motion is really a backstop for when that request is ignored or refused.

A judge hearing this motion isn't deciding whether the allegations are true, only whether enough detail has been given to let you meaningfully respond and know the case you have to defend. If ordered, the other party must file particulars, which then become part of the pleadings. This motion is usually brought early, since you typically aren't required to file your own defence until proper particulars are provided, and getting the details clarified early can also reveal that a claim is weaker, or stronger, than it first appeared.