About half the internet experts claim that front sway bar links should be replaced in pairs. Does anyone know what Toyota says?

no real reason to replace them in pairs other than they would both have the same amount of miles on them. you can just replace one if needed

Anything suspension should be replaced in pairs. I don't think Toyota would bother documenting something like this when there are so many variables. You are just wasting labor money and creating the next failure point by replacing one.

When I break them I tend to only break one at a time, so I replace one at a time. However, I recently broke a link for the third time and removed the bar altogether. No major complaints. Can't drive it like a Supra anymore though...

If old and worn out, Replace in pairs.

Also, you don’t want one breaking off and damaging the CV boots. Front sway bar links are way cheaper then replacing a CV boot.

You can replace just the bad one and be fine.
There's no compelling reason to do both, but if one's bad the other could be close. At least check it.

I've found that most things wear out in pairs anyway. And if you're going through the trouble of doing one it does make sense to do the other... however, this rule only applies, for me, when doing something that's just "had it's day and needs replaced"

Things that I broke... because of some change I made or just me hammering on it too hard, I would likely only replace the failed part.

For endlinks, it would depend on why it failed. End of life, replace both. If broke due to abuse, just replace the one that broke.

If broken several... may want to re-access the bigger picture.

I removed my front sway bar and the links. Nothing to worry about in the future.

Keros spelled out a reasonable approach. The swaybar is a spring, similar in function to a torsion bar. It's purpose is to transfer force from one wheel to its companion on the other side of the vehicle. This means that as one endlink has upward force applied to it during cornering, the opposite side has downward (opposite) force applied to it. The endlinks work as a team.

So, as Keros described, for normal wear I replace both endlinks. If one side is failing for some other reason e.g. being struck by a rock during off-roading, the broken one gets replaced...and I'd investigate armor options to protect it.

If the swaybar is bent, it will preload both endlinks (in opposite directions) and accelerate wear. It may be necessary to remove the swaybar and check it for straightness on a level surface.