Failure to cast a spell

[Hylobius]

If I script a battle field spell and have the required path and school levels, the required gems, range is not an issue, and the dang mage decides to cast something else, what other factors can cause this?

Thanks

[thejeff]

Since the example requires gems, the most likely cause is that the AI decided not to waste gems on that battle. Was the opposition weak?

[Hylobius]

Yes I think that the opposition has been weak when this has happened. I did not realize that the AI would evaluate the strength of the opposition and not use a spell that was overkill.

[thejeff]

It tries to avoid using gems without need. This is too avoid tactics like breaking siege with a single scout when you expect to be stormed, in the hopes the enemy won't have gems left for the real battle.