termi: Skill for Cursor

Worked example based on how InternalProvider and the test-only MockSafProvider are structured. Follow this shape for any new storage backend (SSH/SFTP, a future cloud-sync provider, etc.).

1. Implement the FsProvider trait

// rust/src/vfs/ssh_provider.rs (example — doesn't exist yet)
use crate::vfs::provider::{DirEntry, FileMetadata, FsProvider};
use crate::utils::error::{VfsError, VfsResult};
use std::path::Path;

pub struct SshProvider {
    // connection state, session handle, etc.
}

impl FsProvider for SshProvider {
    fn read_file(&self, path: &Path) -> VfsResult<Vec<u8>> { /* SFTP read */ todo!() }
    fn write_file(&self, path: &Path, contents: &[u8]) -> VfsResult<()> { todo!() }
    fn metadata(&self, path: &Path) -> VfsResult<FileMetadata> { todo!() }
    fn list_dir(&self, path: &Path) -> VfsResult<Vec<DirEntry>> { todo!() }
    fn create_dir(&self, path: &Path) -> VfsResult<()> { todo!() }
    fn delete(&self, path: &Path) -> VfsResult<()> { todo!() }
    fn rename(&self, from: &Path, to: &Path) -> VfsResult<()> { todo!() }
    fn exists(&self, path: &Path) -> bool { todo!() }
    fn is_dir(&self, path: &Path) -> bool { todo!() }

    // Only override chmod/symlink if SFTP genuinely supports them for
    // this backend — many SFTP servers DO support chmod (unlike SAF), so
    // this is a case where you'd actually implement it rather than
    // inheriting the "not supported" default:
    fn chmod(&self, path: &Path, mode: u32) -> VfsResult<()> {
        // real SFTP SETSTAT call
        todo!()
    }
    // Don't override symlink/readlink unless the SSH server's filesystem
    // actually supports it — check before assuming.
}

Don't forget #[warn(clippy::unwrap_used)] compliance — no .unwrap() in the real implementation, propagate VfsError via ?.

2. Register it with VfsService, not standalone

let mount = MountPoint::remote("/mnt/home-server", "ssh://user@host", "Home Server");
let provider: Arc<dyn FsProvider> = Arc::new(SshProvider::connect(...)?);
vfs_service.mount_provider(mount, provider)?;