beads: move worktree/workspace validation to server-side

internal/p9/beads.go

@@ -186,6 +186,21 @@ func (b *BeadsFS) Mount(name, cwd string) error {
 			return fmt.Errorf("mount path must be exactly 1 level deep from project dirs (%v)", config.ProjectDirs)
 		}
 	}
+	// Reject if cwd is a git worktree (not the main repo)
+	gitPath := filepath.Join(cwd, ".git")
+	if info, err := os.Stat(gitPath); err == nil && !info.IsDir() {
+		return fmt.Errorf("mount path is a git worktree, not a base repo — mount the parent project instead")
+	}
+	// Reject if cwd contains git worktrees (feature workspace, not base workspace)
+	entries, _ := os.ReadDir(cwd)
+	for _, e := range entries {
+		if e.IsDir() {
+			subGit := filepath.Join(cwd, e.Name(), ".git")
+			if info, err := os.Stat(subGit); err == nil && !info.IsDir() {
+				return fmt.Errorf("mount path contains git worktrees — this is a feature workspace, mount the base workspace instead")
+			}
+		}
+	}
 	// Warn if new mount overlaps with existing mounts
 	for _, m := range b.mounts {
 		if strings.HasPrefix(cwd, m.cwd+"/") {

mcptools/mount_beads.sh

@@ -20,18 +20,6 @@ if [ -z "$CWD" ]; then
     exit 1
 fi
 
-# Reject if CWD is a git worktree (not the main repo)
-if [ -f "$CWD/.git" ]; then
-    echo "error: $CWD is a git worktree, not a base repo — mount the parent project instead" >&2
-    exit 1
-fi
-
-# Reject if CWD contains git worktrees (feature workspace, not base workspace)
-if find "$CWD" -maxdepth 2 -name ".git" -type f 2>/dev/null | grep -q .; then
-    echo "error: $CWD contains git worktrees — this is a feature workspace, mount the base workspace instead" >&2
-    exit 1
-fi
-
 MOUNT=$(uuidgen | cut -d- -f1)
 
 echo "mount $CWD $MOUNT" | 9p write anvillm/beads/ctl