35 USC §112 requires that patent claims particularly point out and distinctly claim the subject matter which the applicant regards as the invention. With the recent Supreme Court case of Nautilus, Inc. v. Biosig Instruments, Inc., 134 S. Ct. 2120 (2014), many predicted a significant impact on prosecution before the USPTO, where Examiners would require applicants to further amend claims by pointing out potential clarity issues. In Nautilus, The Supreme Court replaced the previous "insolubly ambiguous" standard with the "reasonable certainty" standard.
Indeed, it seems Examiners have taken the queue and have a tendency to question claim meaning at a higher rate than before. However, simply because Examiner allege lack of definiteness does not mean amendments are always required.
In a recent PTAB case, the Board made clear that simply alleging a lack of clearness, without a proper explanation, is not proper. US application 12/260,445 relates to a procedure for liquefying dewatered sewage sludge, also known as reactor-sludge, to a target viscosity. The Examiner rejected the claims with many assertions of unclarity and posing many questions, but without any real analysis. The rejection of claim 1 is reproduced below.
The Board summarily rejected this approach. Specifically, the Board explained that the Examiner "fails to establish that any of these recitations prevent the claims, viewed in light of the Specification, from informing those skilled in the art of claim scope with reasonable certainty." The Board considered the very first allegation from the Examiner and found it improper as the claim did properly identify the recited “dewatered event-sludge” as being “in the sludge-liquefaction event.” The Board then summarily dismissed all of the remaining 112 rejections by noting that "[a] similar analysis reveals that none of the Examiner’s many criticisms of claim language establishes a prima facie case for the proposition that those skilled in the art, when reading the appealed claims in light of the Specification, would be unable to assess with reasonable certainty the scope of Appellants’ claimed procedure."
This example shows that even under the Supreme Court's new standard, the Examiner must still articulate proper reasoning and cannot simply allege features are unclear and ask inane questions.