For the safety and comfort of library patrons, pets, companion, and therapy animals are not permitted in the library unless for authorized library programs. Service animals are permitted.
A service animal is defined by the Americans with Disabilities Act as one that is "individually trained to perform tasks for people with disabilities."
Staff can ask if your animal is a service animal, and what tasks it has been trained to perform. Under the ADA and Oregon state law, they cannot ask what your disability is or ask you for documentation.