Predict Double Hand

Switches to a hotbar totem when a hit that could kill you is coming.

Keeps a second totem ready in your hand for when the offhand one pops. It checks the nearest enemy within 10 blocks every tick.

End crystals nearby that would kill you if they went off.

Charged respawn anchors nearby that would kill you.

Obsidian and bedrock the enemy can reach, with room on top for a crystal that would kill you.

An enemy above you falling with a mace, judged from how fast they're dropping.

An enemy holding a sword or axe while you're on less than half a heart.

Switch to the totem straight after you throw a pearl.

Do nothing while Auto Crystal or Crystal Aura is on.

Do nothing while you're blocking with a shield.

How long to wait after switching before it can switch again.

Damage guesses are multiplied by this before they're compared with your health, so higher switches earlier. From 0.5 to 2.