A claim amendment can be substantively right and still go nowhere. A wrong status identifier, markings shown against the wrong version, or a canceled claim reproduced in full can draw a notice of non-compliant amendment, and an inserted phrase without support in the application as filed can draw a new matter rejection. Neither problem has anything to do with whether the amended claim is patentable.
This guide covers the mechanics of amending claims in a reply to a USPTO office action: the claim listing required by 37 CFR 1.121, the status identifiers, how changes are marked, how to show written description support, and what to recheck once the claims change. It is general information about US practice, not legal advice for any particular matter.
The Claim Listing: Every Claim, Every Time
Under 37 CFR 1.121(c), claims are amended by rewriting the entire claim with its changes marked, inside a complete claim listing. The listing replaces every earlier version of the claims in the application, so it must include every claim ever presented, in ascending numerical order, each with a status identifier in parentheses.
Canceled and not entered claims are listed by number and status only, without their text, and consecutive claims with the same status can be grouped, for example "Claims 5-7 (Canceled)". New claims are numbered consecutively from the highest number previously presented under 37 CFR 1.126, so a canceled claim's number is never reused.
The Status Identifiers
Each claim in the listing carries one identifier describing its status as of this amendment:
- Original - the claim as filed, never amended.
- Currently amended - changed in this paper, with the changes marked.
- Previously presented - added or amended in an earlier paper that was entered, and unchanged now.
- New - added in this paper, presented without markings.
- Canceled - removed, listed without text.
- Withdrawn - withdrawn from consideration, typically after a restriction requirement. A withdrawn claim being changed is shown as withdrawn and currently amended, with markings.
- Not entered - presented in an earlier paper that the examiner did not enter, listed without text.
Most identifier mistakes come from tracking status by memory. A claim amended in the last reply is "Previously presented" now, not "Currently amended". A claim from an after-final amendment that was never entered still sits at its last entered version. And homemade labels such as "Previously amended" invite a notice even where the Office has tolerated nonstandard identifiers in the past. The listed set is the safe set.
Markings: Show Changes Against the Last Entered Version
A currently amended claim shows its changes against the immediately prior version of that claim, which means the last version actually entered, not the claim as originally filed and not a draft that was never filed. Added text is underlined and deleted text is shown in strike-through. Double brackets may be used instead to delete five or fewer consecutive characters, or where strike-through would be hard to see.
1. (Currently amended) A sensor system comprising: a temperature sensor; a controller configured to adjust a sampling interval; and a stored calibration profile that maps each temperature band to a sampling interval.
Two consistency checks prevent most marking errors. Every claim marked "Currently amended" should show at least one change, and no claim with any other identifier should show markings. A claim whose markings were generated against the wrong baseline is the hardest error to spot by eye, which is why the baseline should come from the prosecution record rather than a local file.
Support in the Application as Filed
Under 35 U.S.C. 132(a), no amendment may introduce new matter into the disclosure, and amended claims must still satisfy the written description requirement of 35 U.S.C. 112(a). The MPEP asks applicants to point out where the support for an amendment can be found, and doing so in the remarks is the simplest way to avoid a new matter rejection.
- Cite support per inserted phrase - a paragraph or page and line for each piece of new claim language, not one citation for the whole amendment.
- Remember the original claims - claims as filed are part of the disclosure and can supply support of their own.
- Watch negative limitations - excluding something requires support for the exclusion, not just silence in the specification.
- Check carved-out ranges - a narrower numerical range needs support for its new endpoints, not merely for the broader range.
- Avoid paraphrase - wording that is close to the specification but not in it is exactly where support disputes start.
What Changes When the Claims Change
Amending one claim ripples through the rest of the listing. Before the reply is filed, recheck:
- Antecedent basis - an amendment that renames or removes an element can leave "the" or "said" references in dependent claims pointing at nothing, which invites an indefiniteness rejection.
- Dependency - claims that depend on a canceled claim need to be amended or canceled, and new dependent claims need a valid parent.
- Excess claim fees - fees under 37 CFR 1.16(h) and (i) apply for each independent claim over three and each claim over twenty, with a separate fee for multiple dependent claims, and an amendment that pushes the counts above what has already been paid owes the difference.
- After-final limits - once an action is final, amendments are entered only within the limits of 37 CFR 1.116, which we cover in our guide to options after a final rejection.
- Prosecution history - narrowing amendments made for patentability can limit equivalents later, so each one should be a deliberate choice.
The remarks should also explain how the amended claims avoid each cited reference. Under 37 CFR 1.111(c), an applicant who amends in reply to a rejection must clearly point out the patentable novelty the claims present in view of the art, which is why the amendment decision belongs in the office action analysis rather than at the end of drafting.
How Design Your Invention Handles the Claim Listing
The office action response workspace in Design Your Invention builds the claim listing from the examined claims in the prosecution record, so markings are always shown against the right baseline. Each claim carries its status, and claims are parsed deterministically, including multiple dependent claims and Markush groups. Possible antecedent basis gaps are flagged on every claim change, and excess-claim counts update as the listing changes.
Inserted language is linked to passages in the application as filed, which an attorney confirms, and added words that no cited passage holds are flagged before approval. The response is approved by an attorney who did not last revise it, approved content is locked, and the reply is exported to Word for the attorney to file. When AI assists with amendment proposals, the same support checks apply, as we explain in our guide to using AI on office action responses.
An amendment is a legal argument written in claim language. Get the listing, the markings, and the support right, and the examiner is left with only the argument to answer.