Can a player use Find Steed to summon a creature in a location they have never seen?

Question

The spell Find Steed has a range of 30ft and describes where your summoned steed appears using the language:

"Appearing in an unoccupied space within range, the steed ..."

My question has two parts:

1. Does this language imply that the steed can appear in a space that the player cannot see? If so, can the space be one the player has never seen?
2. Who determines (the player or DM) in what space the steed appears?

More concretely:

My player wants to stealthily assassinate an NPC. He goes to her house and stands beneath her window while she is asleep. He has never been inside her room before. He cannot see into her room (the windows have curtains). Can he summon a steed inside her room to do his dirty work for him?

In game, I let my player do this because I thought it was very clever. However, after the session, we've been looking into the RAW and can't find an answer we are satisfied with.

The spell text seems to allow for this exact thing, but we are curious if there are rules elsewhere in the books or if any rule clarifications have been made that prevent this cheeky use of the spell.

Initial discussions:

As we see it the argument for being allowed to do this is that the spell specifically omits the "appears in an unoccupied space that you can see within range" line that is used in other conjuration spells like Conjure Animals and Conjure Celestial, which seems to imply this was a deliberate decision and therefore that this is a valid use of the spell.

On the other hand, the argument could be made (although we have no RAW support for this) that, logically speaking, you would have to be either able to see the space you want to summon the creature into or at least be familiar with it enough to visualize it (for instance, you could make the steed appear in your room from outside because you can picture it, but not in a room you have never been into before).

Of course all of this presupposes that the player is the one that chooses where the steed appears (something we have always just assumed is the case). However, now that we are scrutinizing this, we are wondering if when a spell uses the term "appears" the player does not get any choice on where the creature appears, rather it is left solely to the DM to choose a 'natural' location from the perspective of the summoned creature.

Any additional perspectives would be much appreciated!

Answer 1

No, you can't.

While a locked-room mystery where the victim was apparently kicked to death by a horse is completely hilarious, it doesn't actually work in this case.

The key here is the Targets section of the spellcasting rules:

A typical spell requires you to pick one or more targets to be affected by the spell's magic. A spell's description tells you whether the spell targets creatures, objects, or a point of origin for an area of effect...

To target something, you must have a clear path to it, so it can't be behind total cover. If you place an area of effect at a point that you can't see and an obstruction, such as a wall, is between you and that point, the point of origin comes into being on the near side of that obstruction.

So your horse will, unfortunately, appear on this side of the door rather than inside the room.

But find steed doesn't have a target!

Well, yes, it does. As far as I can see, every spell has a target in some way that describes where or to whom or what the spell is happening.

The target of the spell in this case is the "point of origin", that is, space you've chosen to summon the steed into, and the effect of the spell is the steed itself. This is pretty standard for conjuration spells. Many of them specify that you need to actually see the space, but find steed does not, instead only requiring the clear path, and thus usable while blind or in darkness. (Even if you decided to rule that the 'target' is the steed that's being created, well, you still don't have clear path to the steed inside a closed room, so it still fails either way.)

In 5e, the term 'target' is somewhat vague and contextual. A target is anything being affected by the spell, even if the spell doesn't specifically state it, but the intent of the rule seems pretty clear to me: You need a clear path to whatever your spell is doing, unless the spell specifically says it doesn't or the shape it takes allows you to do some tricks -- like for example hitting people around a corner with a fireball because it specifically says it spreads around corners.