While your agent may not be responsible for disclosing material facts about your property to potential buyers, they can be held accountable if they had knowledge of a problem that they failed to make known or tried to hide. Agents are not expected to take on the role of a home inspector. However, an agent should use their best judgment and bring up anything that seems suspicious with both the seller and buyer.
The seller is not obligated to tell a buyer why they are putting their home up for sale. However, failure to disclose a large issue may complicate or delay the sale, frustrating all parties involved.
If there is a problem with your property, it is a good idea to either get it fixed prior to sale or lower your asking price to cover any necessary renovations.