What action is the examiner not allowed to take if a claim is indefinite?

When a claim is deemed indefinite, it lacks the clarity necessary to distinguish the invention from prior art and to inform the public about the boundaries of the claim. This is a critical requirement under 35 U.S.C. 112(b), which states that the claims must be written in a manner that distinctly claims the subject matter the applicant regards as their invention.

Disregarding any possibility of multiple interpretations is not an action the examiner is allowed to take, as one of the key roles of the examiner is to ensure that claims are clear and precise. If a claim has multiple interpretations, it does not meet the requirement for definiteness and therefore could lead to confusion regarding the scope of patent protection. An examiner, faced with such a situation, is obligated to identify this indefiniteness and may reject the claim on those grounds.

In contrast, rejecting the claim as indefinite is an appropriate action for an examiner, as is rejecting the claim based on prior art, because those actions align with the examiner's responsibilities of analyzing and adjudicating the clarity and patentability of the claims. Assuming only one interpretation of the claim also contradicts the examiner's duty to fully assess the claim's clarity. Therefore, the assertion that an examiner is allowed to disregard the potential for multiple