This came up in my session tonight. My players all had the cash to buy war horses and outfit them, I ruled that they're readily available in Neverwinter which they were near for their last adventure.
However, there are two bits of text that I'm trying to piece together and figure out how they work. The first is the following from the mounted combat text:
It moves as you direct it, and it has only three action options: Dash, Disengage and Dodge (PHB 198)
Does this mean that you cannot under any circumstances use your mount's attack (such as the Warhorse's Trampling Charge/Hooves attack)?
Reading the next section it really seems to come down to whether or not a Warhorse is considered an intelligent mount or not, answers should address this.
Best Answer
Yes, a mount can attack as it is being ridden
From Controlling a Mount (PH 198):
(Similar wording appears in the Player's Basic Rules on p77, under the Controlling a Mount section.)
These are 2 separate sentences. The first sentence applies to mounts. The second sentence applies to intelligent creatures. While an intelligent creature can be ridden, they are not classified as mounts, and any attempt to refer to a dragon as your mount may have unintended consequences (eg - being eaten).
If the player decides to control their mount then:
If the player decides to let the mount act independently then:
I would allow a player to switch between controlling a mount and letting it act independently in combat, but I would say they have to spend an action for each switch.