Okay basically regarding self defense in Canada Acti you can't be carrying a tool or weapon on yourself for the premise of defending yourself.
If you have a tool on your and you defend yourself with it without going "on the attack", you're gonna be fine.
The risky thing is getting pocket checked or getting arrested while charged for something else unrelated without a good reason for having weapons or tools on you, it can add fines or prison time.
So let's say you have pepper spray on you and you get pocket checked by a police officer, if you tell them you're carrying pepper spray for self defense, that's a crime.
If you tell them instead that you're terrified of dogs and you've been chased before and therefore you're carrying pepper spray to defend yourself from dog attacks. Then you're likely to be fine.
Getting stopped while carrying a certain types of knives and saying it's for self defense=crime
The types of knives in question:
Prohibited knives: Any knife that has a blade that opens automatically by gravity, by centrifugal force, or by hand pressure applied to a button, spring or other device in or attached to the handle of the knife (butterfly knives, switchblades, etc.) is a prohibited item and is considered an illegal item under the Criminal Code of Canada.
Getting stopped while carrying a canif/utility knife and having a non outlandish purpose you're okay.
IE "I carry a canif because where I grew up it's normal to have one in the forest". And you'll be fine unless the police officer is trying to get you for another crime aswell.