Getting Vanille AI to cast Death

I've recently gotten the spell Death for Vanille in Final Fantasy 13. In general I have the AI control Vanille and it's done quite well in controlling her. However I've noticed ever since getting Death she's failed to cast in once. Even after completely debuffing all enemies she prefers to sit idle and do nothing rather then cast Death. I tried taking control of her to make sure she indeed has it and there wasn't some funky bug but I was able to cast it while I was in control. Is there something I'm missing on why the AI won't cast death?

Solution 1:

Each character has one unique ability that none of the others have. The AI will never use them, so they're only available if you're controlling the character and you use them manually.

• Vanille: Death
• Fang: Highwind
• Snow: Sovereign Fist
• Lightning: Army Of One
• Sazh: Cold Blood
• Hope: Last Resort

This is kind of unfortunate for Vanille, since if you like to use her as a medic the AI does a much better job and you're rarely in control of her.

(source)

Solution 2:

Death is a Full ATB Skill. The AI will not use a Full ATB Skill; you must select this action manually:

In order to perform these moves player must manually select them during the battle, meaning the A.I.-controlled battle members will never use them and auto-battle will not select them.

This implies that Vanille must be the leader of the battle team to use Death.