What exactly can pass through Leomund's Tiny Hut?

Question

The description talks about "creatures and objects." It also mentions that "Spells and other magical effects can’t extend through the dome or be cast through it." I've seen posts on Dragon's Breath and I can understand that would pass through as it's not an object or a creature or a magical effect. But want about regular (non magical) fire? Poison gas? Smoke? The description also says, "The atmosphere inside the space is comfortable and dry, regardless of the weather outside." Since the atmosphere is comfortable and dry, does that mean only when it's created or that it stays that way? Could an enemy smoke a party out of the Tiny Hut or worse, burn them out? It would seem this would make it worthless as it would be easy to kill everyone inside while they sleep but I can't find anyone speaking to those situations specifically.

Answer 1

The hut keeps out weather, magical effects, creatures and objects, but ask your DM

Tiny Hut says:

The atmosphere inside the space is comfortable and dry, regardless of the weather outside.

The statement of comfortable and try atmosphere is only in relation to the weather outside. The hut does not create such an atmosphere against other sources, and it does not create breathable air.

Object is a defined game term and under this definition poison gas or heat is not an object.

Therefore, natural poison gas, or heat from a natural fire will affect the inhabitants of the hut, just like poison gas or heat from dragon breath. Technically, fire or poison gas from dragon breath is no different than any other mundane fire or poison gas. As will any other non-magical effect that is neither a creature, object, nor caused by the weather.

(There may be a fringe case for alien environments in the Abyss or such, where poison gases occur as part of the weather. Those should be kept out).

Because tiny hut is an ritual, it is a really good spell — it does not cost you a slot, and it does cost no preparation. I track how often I cast spells with my wizard, and it is one of my most often used spells. It still is good, even if it allows smoke or heat to pass. Firstly, the monsters outside might not know the spell, and might not know smoke would pass through. Secondly, you can shoot out with arrows, so setting up fire nearby is perilous.

That said, check with your DM. Even though the spell does not simply say the atmosphere is fine, full stop, the normal use of the sphere is to enable safe resting. If someone can smoke you out that makes it a less useful spell. The DM may be fine with ruling the atmosphere hedges out normal gas or fire, where it does not for the poison gas or fire from dragon breath. Or even from dragon breath if its not "special".