Must the Description Be Adapted When the Claims Are Amended? — G 1/25 on Description Adaptation

Anyone who has prosecuted a European patent application will be familiar with description adaptation.

Once the claims have finally been amended into an allowable form, there is often one more rather cumbersome task: adapting the description. Which embodiments need to be deleted? Which statements need to be amended? And which parts of the description can simply remain as they are? The answers have not always been straightforward, not least because the Boards of Appeal themselves have taken different approaches to this issue.

Against this background, the referral in T 697/22 attracted considerable attention. On 3 September 2026, the Enlarged Board of Appeal finally handed down its decision in G 1/25.

1. If the claims are amended, must the description be adapted?

G 1/25 arose from T 697/22. The claims at issue had been amended to include a narrower definition of the binder, while paragraphs [0013] and [0016] of the description retained broader wording.

The first question referred to the Enlarged Board was therefore whether, where an amendment to the claims introduces such an inconsistency, it is necessary to adapt the description in order to comply with the requirements of the EPC. The Enlarged Board was also asked to clarify the legal basis for any such requirement and whether the same approach applies in examination and opposition proceedings.

The Enlarged Board’s answer is conditional. Where an amendment to the claims introduces an inconsistency between the amended claims and the description or drawings, and that inconsistency results in non-compliance with Articles 52 to 57, 76(1), 83, 84, 123(2) or 123(3) EPC, the description or drawings must be adapted to remove the inconsistency.

Two points are particularly important.

First, there is no single provision of the EPC that provides a general legal basis for description adaptation. The relevant legal basis depends on which requirement of the EPC is not complied with as a result of the inconsistency.

Second, the mere existence of an inconsistency does not, by itself, trigger an obligation to amend the description. If the inconsistency has no such legal effect, it need not be removed merely to bring the description formally into line with the claims. As the Enlarged Board expressly stated, the EPC does not require “purely formal concordance” between the claims and the description.

This makes the next question crucial: what amounts to an “inconsistency” for the purposes of G 1/25?

2. Is subject-matter outside the claims necessarily an inconsistency?

No. This is perhaps the most important aspect of G 1/25.

The Enlarged Board expressly held that an inconsistency is not established merely because the description or drawings contain technical teaching, examples or embodiments that are not encompassed by the claimed subject-matter.

In its Press Communiqué issued on the same day as the decision, the EPO gives a useful example in the context of Article 84 EPC: an inconsistency may affect compliance with Article 84 where it leaves it unclear whether information, examples, subject-matter or embodiments fall within the scope of the claim.

The distinction matters. The problem is not that an embodiment remains in the description even though it is no longer covered by the final claims. If the skilled person can clearly understand that the embodiment is disclosed in the description but falls outside the scope of the claim, its mere presence does not establish an inconsistency within the meaning of G 1/25.

The problem arises where the description makes it unclear whether the embodiment is outside the claim or remains part of the claimed subject-matter.

This is also why G 1/25 must be read together with G 1/24. Under the principles established in G 1/24 and further explained in G 1/25, the description and drawings must always be consulted when interpreting the claims. Claim interpretation is not a sequential exercise in which the claim is first construed in isolation and the description is consulted only if the claim is found to be unclear. Instead, the claims, description and drawings are considered together in a “unitary process” or “holistic approach” to claim interpretation.

Against that background, G 1/25 defines when an inconsistency exists. An apparent conflict between the claims and the description does not necessarily amount to an inconsistency. Many apparent incompatibilities can be resolved by applying the principles of claim interpretation set out in G 1/24. An inconsistency exists where the description or drawings suggest an understanding of the claim that is incompatible with its apparent meaning, and that incompatibility cannot readily be resolved by applying those principles, leaving the skilled person in “real doubt as to the meaning of the claim.”

Put simply, the issue is not whether the description contains subject-matter outside the claims. The issue is whether it is clear that the subject-matter is indeed outside the claims.

There is also an interesting aspect of the amicus curiae debate in G 1/25. Both Michael Schmid and the IP Federation argued against mandatory description adaptation merely to eliminate differences between the claims and the description. Their submissions pointed to the role of national courts and the UPC in determining claim scope after grant, and to the tools available to courts for dealing with differences between the claims and the description even where the latter has not been formally aligned with the claims.

The relevant submissions relied on examples from both the UPC and the German courts. In Agfa v Gucci (UPC_CFI_278/2023), the Hamburg Local Division was faced with a discrepancy between broader statements in the description and the granted claim. It held that statements in the description that were inconsistent with the granted claims could not serve as a basis for a broader interpretation of the claim. The case therefore illustrates that even where the description has not been fully aligned with the claims before grant, the court can deal with the discrepancy through claim interpretation.

The submissions also referred to the German Federal Court of Justice’s decision in Okklusionsvorrichtung (X ZR 16/09). That case concerned infringement by equivalents. The BGH held that where the description discloses several ways of achieving a particular technical effect, but only one of those alternatives has been included in the claim, the use of one of the other alternatives will generally not constitute infringement by equivalent means.

These were, of course, arguments advanced in the amicus curiae submissions. G 1/25 itself neither cited nor adopted these decisions, and they concern legal questions different from description adaptation in EPO proceedings. Nevertheless, these examples illustrate why the mere presence in the description of subject-matter outside the claims should not automatically be equated with a need to amend the description.

3. When should the description be adapted?

G 1/25 also contains some noteworthy procedural observations, particularly when read against the background of T 697/22 itself.

In T 697/22, the proprietor did not submit a further amended description deleting the disputed paragraphs [0013] and [0016] until the oral proceedings before the Board. The relevant Article 84 EPC objection had already been raised at the beginning of the appeal proceedings, and the proprietor had not explained why the amendment was submitted only at the oral proceedings. The Board therefore did not admit the request.

In its obiter remarks, however, the Enlarged Board stated that, from a procedural-law perspective, amending the claims and adapting the description or drawings to remove an inconsistency introduced by that amendment are “part of the same procedural step”, even where there is a lapse of time between the two.

The Enlarged Board also observed that, in appeal proceedings, the description and any drawings are “almost always finalised in the oral proceedings before the Board”, and that nothing in G 1/25 calls for a change to that practice. Where adaptation is necessary, dealing with it while the appeal is still pending will generally also be more efficient than remitting the case solely for the description to be adapted.

4. Concluding remarks

G 1/25 does not bring description adaptation to an end. But it does make the relevant inquiry considerably clearer: The mere presence in the description of subject-matter that is not encompassed by the claimed subject-matter does not, in itself, establish an inconsistency. The question is whether that material gives rise to an inconsistency within the meaning of G 1/25 and, if so, whether that inconsistency results in non-compliance with a requirement of the EPC. If it does not, the EPC does not require amendment merely to achieve formal concordance between the claims and the description.

For applicants and practitioners, this is perhaps the most practical consequence of G 1/25. After amending the claims, the exercise should no longer be a mechanical search for everything in the description that is not covered by the claims. The question is whether the remaining material actually gives rise to an EPC issue that needs to be resolved.

The story of G 1/25 is not quite over, however. The Enlarged Board did not itself decide how paragraphs [0013] and [0016] of the description in T 697/22 should ultimately be dealt with; rather, it answered the questions of law referred to it by the referring Board. It remains for that Board to apply the principles established in G 1/25 to the case before it: do the broader statements concerning the binder in those paragraphs give rise to an inconsistency within the meaning of G 1/25? If so, does that inconsistency result in non-compliance with a requirement of the EPC, and how should it ultimately be dealt with? The eventual decision in T 697/22 will therefore be worth watching, as it may provide a useful indication of where the line drawn by G 1/25 lies in practice.

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