What
Claude Code keeps an in-memory copy of a session's messages, called a cache. A new switch, keepSessionMessagesCache, is off by default and is set through setKeepSessionMessagesCache. While it is on, clearSessionMessagesCache does nothing, so the stored messages are kept.
Why
This is internal behavior with no visible change by default. It lets some part of Claude Code keep a session's messages that would otherwise be cleared.
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubt
The finding does not say what turns this switch on.