According to the OW rules , there is no entitlement when travelling domestically
From
https://www.oneworld.com/airport-lounges?location=BOS
Originally Posted by OW
American Airlines AAdvantage members, regardless of their tier status or class of travel, are not eligible for lounge access when travelling solely on domestic U.S. flights (some exceptions apply).
The lounge access exception applies to all lounges, not just AA's lounges
Or are you actually meaning when connecting from an eligible international flight?