How-to: mount a workspace

sturn mount exposes a workspace tree as a real filesystem — the interception layer: tools write normally, sturn records ops.

agent's write_file() ──► kernel ──► FUSE ──► SturnFs
                                          write() → buffer
                                          release → Op::Write → WAL

FUSE = Filesystem in USErspace: syscalls route to a user process instead of a disk driver, so sturn-fuse decides what "a file" means — ops, not bytes on disk.

Use

$ sturn mount devin /mnt/devin        # read-only view of the tree
$ sturn mount --rw devin /mnt/devin   # writes become WAL ops

Under --rw, plain POSIX writes — echo, editors, build tools, agent write_file — land as Write/Rename/Delete ops with intent: "fuse". The agent can't bypass the write path: it is a filesystem, the thing tools already use.

Semantics

• Buffer-then-commit: write() buffers per open file; the op emits on release (close) or fsync — editors that fsync-per- save get an op at sync point, not just at close.
• Mount-time view: the tree is the ws tip at mount time — other agents' ops don't appear live (unmount/remount to see).
• Dirs are implicit in git trees — mkdir/rmdir are local only; a Write op into the dir is what persists.

$ fusermount -u /mnt/devin