StripUnresolvedLinks runs before every brain_write and brain_update. Any walk error below a linked tree's root (e.g. one unreadable subdirectory) made it return an error, and the write was refused: the learning was lost. Already true on main. It now logs a warning and returns the content unchanged: a partial index cannot tell an invented link from one into the unreadable part, so it unwraps nothing (never inventing a resolution) and the note is written with its links as given. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>