What
Claude Code remembers which files Claude has read so it can tell when a file changed afterwards. Sometimes that memory is refreshed after a file changes on disk, without Claude being shown the new contents. Edit now treats a read like that as out of date, whatever the file's last-modified time says. The edit fails with the stale-read error unless it still applies to the file as it is now.
Before, a read only counted as out of date when the file had been modified after it was read and its contents differed.
Why
This stops Claude from editing a file based on a version of it that it never actually looked at.
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubt
Not every situation that quietly refreshes a file's record is known.