Although explicit references in the claims to features elucidated in the description or in the drawings are only permissible where "absolutely necessary" (Rule 43(6) – see also B‑III, 3.5, and F‑IV, 4.17), claims containing such references should still be searched if these technical features are unambiguously defined by specific parts of the description.
However, where the reference does not clearly identify which subject-matter of the description and/or drawings is to be considered as included in the claim, an invitation under Rule 63(1) should be issued. In the special case of "omnibus claims" (e.g. a claim reading "The invention substantially as herein described"), no invitation under Rule 63(1) should be issued, and subsequently the search report will be designated as complete. This means that subject-matter of the above kind will be dealt with only during examination.
The procedure above should be followed regardless of whether or not the reference to the drawings and/or the description is allowable according to Rule 43(6). In either case, the claim will have the same scope: if the reference is not allowable under Rule 43(6), the applicant will be requested to copy the definition of the technical feature from the description and/or drawings into the claim; if the reference is allowable, the claim will stay as it is.