Severance agreement arrived, need a second opinion (Boston)

My manager said the package is final, but the letter gives me time to review. It has been weighing on me all week. There is a non-disparagement clause. Did anyone negotiate and succeed?

Ask for the offer in writing and do not sign on the spot. A day or two to think is normal.

Keep everything in writing and save the confirmation numbers. It made the follow-up calls so much easier.