The scope of the examination is limited by Rule 95(2). The Examining Division is required to decide only whether the amended claims of the request constitute a limitation with respect to the claims as granted or amended (i.e. those referred to in D-X, 4.2), and whether they comply with the requirements of Art. 84 and Art. 123(2) and Art. 123(3).
The term "limitation" is to be interpreted as meaning a reduction in the extent of protection conferred by the claims. Mere clarifications or changes made to protect a different subject ("aliud") are not to be considered as limitations.
More particularly, the limitation of a dependent claim only, without any independent claim being limited, is acceptable. However, it is not permissible to introduce non-limiting amendments in the description or in the claims that are not a consequence of the limitation of the claims (for example tidying up unclear claims, making amendments to improve the patent or cosmetic changes). Likewise, adding dependent claims in limitation is not permissible if not directly caused by the limitation introduced in the claims.
Amendments in a claim leading to an extent of protection which is smaller, but falls partly outside the extent of protection conferred by the claim previously on file, should be dealt with cautiously. Even if the amendment constitutes a limitation, such a claim would generally contravene Art. 123(3) (see also H-V, 7 for Art. 123(3) in the case of a change of category of a claim).
Rule 95(2) requires the Examining Division to examine only the amended claims. According to Rule 92(2)(d), however, the request for limitation may also comprise an amended description and drawings. In this case such amendments should also be examined with respect to the above requirements. Therefore the examiner checks whether the amended claims are still supported by the description. Amendments made to the description solely in order to improve the patent or cosmetic changes which are not necessitated by the limited claims cannot be allowed.
For interpretation of Art. 84 and Art. 123(2), see F-IV, 4, and H-IV, 4.4. The description and drawings are used to interpret the claims in accordance with Art. 69(1) and its Protocol on Interpretation. Amendments made to these parts might therefore introduce matter contrary to Art. 123(3) (see H-IV, 3.1 and H-IV, 3.3).
There should be no examination as to whether the subject-matter of the limited patent is patentable under Art. 52 to Art. 57 or whether the supposed aim, if indicated, of the limitation (e.g. delimitation with respect to particular prior art) is actually achieved by the requested amendment of the claims.
Errors of transcription or obvious mistakes can, however, be rectified on request or by the EPO of its own motion.
The filing of auxiliary requests together with a main request is possible (see H-III, 3).