Mass. Trial. Ct. R. 1
A subpoena to compel a justice, magistrate or probation officer of the Trial Court to testify concerning actions taken in her or his official capacity shall not be served without the prior approval of the court in which the underlying matter is pending. The party shall seek the necessary order of approval by written motion which hall specify the purposes) for which the testimony' is sought. Except for good cause shown, a copy of such motion shall be served on the justice, magistrate or probation officer whose testimony the party seeks to compel. If the court grants its approval, the party shall serve the subpoena and a copy of the court order approving the subpoena on the justice, magistrate or probation officer. A justice, magistrate or probation officer shall not be required to respond to a subpoena served on her or him unless it is accompanied by a copy of the court order approving the subpoena.
Mass. Trial. Ct. R. 1