Oklahoma does not provide special admission rules for government attorneys licensed in other jurisdictions.
However, Oklahoma provides an Oklahoma Multijurisdictional Practice Rule (MJP) within its rules of professional conduct. Comment 16 to that rule provides for an interpretation that exempts government attorneys from the unauthorized practice of law.
Please also see the Oklahoma Miscellaneous page to view the qualifications for a temporary permit to practice while waiting to take the bar exam or the results of that exam; the Oklahoma Bar Reciprocity page to view the requirements for Admission on Motion, and the Oklahoma Pro Hac Vice page to view the requirements for admission to a particular proceeding.