The Commission, the Council and the European Parliament all run a legal service providing EU decision-makers with legal advice. These services influence all proposals for laws and make thousands of legal notes every year. The legal notes are not made public nor are they accessible by MPs and MEPs.
Legal service of the Council
European Commission Legal Service: http://ec.europa.eu/dgs/legal_service/index_en.htm
The legal service of the European Parliament http://www.europarl.europa.eu/parliament/expert/staticDisplay.do?id=54&pageRank=13&language=EN