The U.S. has a very strict residency requirement for patent agent registration. 37 C.F.R. 11.6(b) provides:
There are ambiguities in the provision but, as far as I know, it isn’t very easy for a foreigner with work visa to satisfy the requirement. To be eligible to be registered,
(i) lawfully reside (work visa will probably do it);
(ii) fulfilles the requirements of this Part (one will probably have to take and pass the patent bar);
(iii) registration as patent agent is not inconsistent with the terms upon which the alien was admitted to,
(iii) is the phrase at issue in Lacavera v. Dudas.
I couldn’t take the patent bar while I was in the U.S. primarily because of (iii).
Interestingly, Canada has a similar law. Canadian Patent Rule Section 12(1) provides:
(a) the person resides in Canada and has been employed for a period of at least 12 months on the examining staff of the Patent Office; or
(b) the person resides in Canada and has worked in Canada in the area of Canadian patent law and practice, including the preparation and prosecution of applications, for a period of at least 12 months.
On the other hand, Korea does not have a residency requirement for patent attorney registration. One only has to pass the patent bar and that will do it.
As noted in the Patently-O blog, if the U.S. and Canada asks other countries to acknowledge U.S. and Canadian patent agent registration, the negotiation counterparts might ask the U.S. and Canada to remove the residence requirements.