U.S. Patent Office Memo: Why Close Calls on Patent Eligibility Should Favor AI and Machine Learning

The U.S. Patent and Trademark Office (USPTO) published on August 4, 2025 guidance reminding examiners how to properly evaluate subject matter eligibility under 35 U.S.C. § 101, with particular emphasis on computer-implemented inventions, including software, artificial intelligence (AI) and machine learning (ML) claims. Although framed as a reminder, the memorandum meaningfully clarifies where eligibility analyses most often go wrong and where well-drafted computer-based claims are most defensible.

The guidance reiterates that subject matter eligibility must be evaluated using the existing framework and that claims should be evaluated as a whole, rather than through piecemeal dissection. The guidance also reminds examiners that a claim limitation qualifies as a mental process only if it can practically be performed in the human mind or with pen and paper. This restriction is particularly relevant to AI- and ML-based inventions, where claimed operations—such as large-scale data processing, model training or manipulation of complex data structures—often cannot realistically be performed by a human. Claims reciting such operations therefore do not fall within the mental process grouping, even if they include concepts that are abstract.

The guidance provides examples and explains that claim language such as “training a neural network” does not, by itself, recite an abstract idea, even though it may rely on mathematical techniques. By contrast, claims that explicitly include specific mathematical algorithms, calculations or formulas may cross the line into reciting an abstract idea. This distinction stresses that patent eligibility often turns on the specific words in the claim, not on what features the invention might rely upon.

For computer-based inventions, the guidance identifies technological improvement as one of the most important considerations to show patent eligibility. Claims that reflect an improvement to the functioning of a computer or to another technical field are more likely to be patent eligible. The guidance acknowledges that the claim need not explicitly recite the improvement but does indicate that the specification should describe the invention in a way that makes the improvement apparent to a person of ordinary skill in the art.

Examiners are instructed to consider whether the claim merely states a desired outcome or instead recites how the solution is achieved, and whether the computer is simply used as a tool or is itself improved. Finally, the guidance provides an important reminder that examiners should not issue a patient eligibility § 101 rejection unless it is more likely than not that the claim is not eligible. That is, uncertainty alone is not a sufficient basis for a rejection, since all rejections must be supported by a preponderance of the evidence. In addition, even where a § 101 rejection is made, examiners are reminded to conduct a complete examination in accordance with compact prosecution principles.

Key Takeaways

For computer-implemented inventions, whether a claim actually recites an abstract idea, as opposed to merely involving one, is frequently dispositive. Technological improvement remains the most reliable pathway to eligibility, and close cases should not result in § 101 rejections absent a clear showing of ineligibility.

Practice Tips — Patent Prosecutors

1. Draft Claims Strategically
   Avoid explicit recitation of mathematical formulas or algorithms unless necessary; claim the functional operation through technical steps.
2. Argue that the Invention Cannot be Performed by the Human Mind
   Explicitly argue that claimed operations cannot practically be performed mentally, including AI/ML architectures.
3. Specification as Eligibility Insurance
   Clearly describe why the invention improves computer performance or other technical advantages—even if the claims do not specifically claim the technical advantage.
4. Frame the Problem the Invention Seeks to Solve Technically
   Define the problem as a technological limitation, not a business inefficiency.
5. Use USPTO Examples Strategically
   Cite Examples provided by the USPTO to show examiner inconsistency with Patent Office guidance.

Practice Tips — Patent Litigators

1. Attack “Mental Process” Overreach
   Force the examiner or challenger to articulate how a human could practically perform the claimed steps.
2. Exploit Recites vs. Involves
   A patent eligibility § 101 rejection could fail because the claim never actually recites an abstract idea.
3. Leverage the “Close Call” Standard
   Argue that uncertainty alone is a legally insufficient reason for a § 101 rejection.
4. Anchor to the Specification
   Emphasize disclosed technical improvements, even where claims are functionally worded and/or do not describe the technical improvement.

is a partner in Manatt, Phelps and Phillip’s Intellectual Property Protection and Enforcement business unit and is the author of Patent Prosecution: Law, Practice, and Procedure, 2025 Edition, and Constructing and Deconstructing Patents (2d Edition).

USPTO Memorandum – Reminders on Evaluating Subject Matter Eligibility of Claims Under 35 U.S.C. § 101 (Aug. 4, 2025).