Mass. Gen. Laws ch. 258 § 7
Any award, compromise or settlement of a civil action brought under this chapter in excess of twenty thousand dollars which has been approved by a public attorney for a public employer, or, in the case where the public employer is the commonwealth, approved by the secretary of administration and finance, shall be made final only after approval of same by a judge of the superior court having jurisdiction over the action.
The acceptance by the claimant of any such award, compromise or settlement shall be in writing and shall, except when procured by fraud, be final and conclusive on the claimant, and shall constitute a complete release of any claim against the public employer or against the public employee whose negligent or wrongful act or omission gave rise to such claim, and a complete bar to any action by the claimant against such public employer or public employee, by reason of the same subject matter.
Mass. Gen. Laws ch. 258, § 7