231 Pa. Code § 4003.3
Subject to the provisions of Rules 4003.4 and 4003.5, a party may obtain discovery of any matter discoverable under Rule 4003.1 even though prepared in anticipation of litigation or trial by or for another party or by or for that other party's representative, including his or her attorney, consultant, surety, indemnitor, insurer or agent. The discovery shall not include disclosure of the mental impressions of a party's attorney or his or her conclusions, opinions, memoranda, notes or summaries, legal research or legal theories. With respect to the representative of a party other than the party's attorney, discovery shall not include disclosure of his or her mental impressions, conclusions or opinions respecting the value or merit of a claim or defense or respecting strategy or tactics.
231 Pa. Code § 4003.3