Today's Federal Register issued final rulemaking, effective September 15, 2008, that proscribes a patent agent from giving an opinion on infringement or validity, except for situations where an opinion of validity is "reasonably necessary and incident to the preparation and prosecution of patent applications or other proceedings before the Office involving a patent application or patent." The PTO states:
Whether a validity opinion involves practice before the Office depends on the circumstances in which the opinion is sought and furnished. For example, an opinion of the validity of another party’s patent when the client is contemplating litigation and not seeking reexamination of the other party’s patent could not be reasonably necessary and incident to the preparation and prosecution of patent applications or other proceedings before the Office involving a patent application or patent. In such situations, the opinion may constitute unauthorized practice of law. See Mahoning Cty. Bar Assn. v. Harpman, 608 N.E.2d 872 (Ohio Bd.Unauth.Prac. 1993). Similarly, a validity opinion for the sale or purchase of the patent is neither the preparation nor the prosecution of a patent application. Likewise, the opinion is not a proceeding before the Office involving a patent application or patent. Registration toThe rules go further by disallowing a patent agent to prepare most patent assignments, with one narrow exception. Specifically, the new rule sanctions
practice before the Office in patent cases does not authorize a person to provide a validity opinion that is not reasonably necessary and incident to representing parties before the Office. In contrast, a validity opinion issued in contemplation of filing a request for reexamination would be in contemplation of a proceeding before the Office involving a patent.
In no circumstance would practice before the Office include the rendering of opinions on infringement. Under the law, the Office has no authority to resolve infringement cases. Thus, registration to practice before the Office in patent cases does not include authority to render infringement opinions. See Mahoning Cty. Bar Assn. v. Harpman, supra.
Drafting an assignment or causing an assignment to be executed for the patent owner in contemplation of filing or prosecution of a patent application for the patent owner, where the practitioner represents the patent owner after a patent issues in a proceeding before the Office, and when drafting the assignment the practitioner does no more than replicate the terms of a previously existing oral or written obligation of assignment from one person or party to another person or party.
Read/download the new rules here (link)
Also see Revision of Patent Fees for Fiscal Year 2009: Final Rule .