Any amendment can only be made within the limits of what a skilled person would derive directly and unambiguously, using common general knowledge, and seen objectively and relative to the date of filing, from the whole of the documents as filed (G 2/10, "gold standard", see above chapter II.E.1.3.1).

The board in T 1269/06 held that, for the assessment of whether, contrary to Art. 100(c) EPC 1973, the subject-matter of the patent extends beyond the content of the application as filed, the key question is whether the amendments made in the description, or – as in the case at issue – the claims, did indeed provide the skilled person with additional, technically relevant information which was not contained in the original application documents. This cannot be inferred from the fact alone that terms not present in the application documents were subsequently introduced, or from a purely semantic analysis of the contested passages. Instead, the party or department raising the objection must be able to identify clearly the technical teaching as such which has supposedly been added.

In T 99/13 the board recalled, in line with the case law (see T 667/08, T 1269/06, quoted in the decision; see also e.g. T 988/91, T 494/09), that the assessment of the requirements of Art. 123(2) EPC should be done on the same basis as for all other patentability issues (e.g. novelty and inventive step), namely from the standpoint of the skilled person on a technical and reasonable basis avoiding artificial and semantic constructions. The skilled person, reading claim 1 as originally filed from the standpoint of a technician working in the field, would read the broad condition expressed therein with regard to the viscosity measurement, as a condition to be met at the temperature of use of the claimed formulation and would turn to the description to find further information in this respect. The description specified that the preferred temperature of reconstitution was 25°C and the viscosity measurement was accomplished at 25°C in all examples but one. The only example specifying a different temperature did not fall under claim 1. The board concluded that the amended viscosity condition with the specification of the temperature of measurement "at 25°C" was directly and unambiguously derivable from the application as filed. See also T 2255/12 which guards against an overly formalistic approach in which more emphasis is given to the literal content of the original application rather than the technical information that it conveys.

Literal support for amendments in a patent application is not required under Art. 123(2) EPC, insofar as the amended or added features reflect the technical information that the skilled person reading the original disclosure would have derived from its content (description, claims and drawings) considered in its entirety (T 1728/12 citing decision T 667/08; see also T 1731/07, T 45/12, T 801/13, T 1717/13 and T 640/14). See also in this chapter II.E.1.3.3 "Implicit disclosure" below.

In T 1717/13 the board noted that the respondent/opponent's objections primarily pointed to differences in the wording between the application as filed and the claim amendments. It was, however, generally accepted that for the purposes of Art. 123(2) EPC an explicit basis for an amendment in the original application documents was not required as long as the amendment was clearly and unambiguously derivable, using common general knowledge, from the application as filed.

The board in T 2619/11 took the view that the focus of the first-instance decision was disproportionately directed to the structure of the claims as filed to the detriment of what was really disclosed to the skilled person by the documents as filed. The application was directed to a technical audience rather that to a philologist or logician, for which audience an attempt to derive information from the structure of dependent claims would lead to an artificial result. T 1363/12 considered that T 2619/11 did not lay down a new test (namely, of what was "really disclosed" to the skilled person) different from the "gold standard" (see in this chapter II.E.1.3.1) (see also T 938/11). See also T 1194/15 (referring to T 2619/11) which accepted in the case at issue that the incorporated features were disclosed in the application as filed as a general disclosure applicable to all embodiment of the invention and considered the contrary approach adopted by the appellant/opponent as very formalistic, without taking into account the type of audience to which the patent is directed.

In T 23/02 the board said that although the claims as originally filed contained no reference to a method of measurement for the average particle diameter, that did not mean that any method could be used to determine that parameter. If anything, the claims raised doubts as to how the average particle diameter had to be determined, in particular because the skilled person would be aware of the fact that the method of measurement was of a decisive nature in particle size analysis. Therefore the skilled person would use the description and drawings when deciding how the average particle diameter was to be measured, and would come to the conclusion that when properly interpreted in light of the original description, the claims as originally filed already contained restrictions as to the method of measurement for the average particle diameter of the various particles. (For the case law on the need to include the measuring method of a parameter in the claim, see however chapter II.C.6.6.8 "Measuring methods".)