See ISPE Guidelines 5.31.[Art. 6; ]
Where it is found that the claims lack clarity, it may be appropriate for the examiner to first invite the applicant to provide informal clarification before the search is carried out (see GL/PCT‑EPO B‑VIII, 3.3-3.6).
Source: http://www.epo.org/law-practice/legal-texts/html/guidelinespct/e/f_iv_4_1.htm
Date retrieved: 17 May 2021