It seems reciprocal perks will continue to be provided - how long this will last is anyone's guess - since they are unraveling the alliance pretty fast, I don't anticipate the perks will last long either - so enjoy while you can. BTW, the JetBlue FAQs provide some details, whilst AA site does not have the same level of detail.

From JetBlue website: https://www.jetblue.com/airline-part...rican-airlines

Do my reciprocal perks still apply when traveling on American Airlines-operated flights?Yes, for bookings made no later than 7/20/23, Mosaic and AAdvantage elite members can continue to enjoy reciprocal perks (provided your TrueBlue or AAdvantage number was added to the reservation no later than 7/20/23). We'll let you know if this changes.

Those perks include:

• Up to 2 free checked bags 
• Free Even MoreŽ Space on JetBlue and Main Cabin Extra on American⁴
• Free same-day switches on JetBlue and Same Day Flight Change⁵ on American
• Priority boarding, expedited security and dedicated check-in