diff --git a/go/vcs/vcs.go b/go/vcs/vcs.go
index c1d0ecd0..a7024966 100644
--- a/go/vcs/vcs.go
+++ b/go/vcs/vcs.go
@@ -478,11 +478,11 @@ func RepoRootForImportPathStatic(importPath, scheme string) (*RepoRoot, error) {
 // RepoRootForImportDynamic finds a *RepoRoot for a custom domain that's not
 // statically known by RepoRootForImportPathStatic.
 //
-// This handles "vanity import paths" like "name.tld/pkg/foo".
+// This handles custom import paths like "name.tld/pkg/foo" or just "name.tld".
 func RepoRootForImportDynamic(importPath string, verbose bool) (*RepoRoot, error) {
 	slash := strings.Index(importPath, "/")
 	if slash < 0 {
-		return nil, errors.New("import path doesn't contain a slash")
+		slash = len(importPath)
 	}
 	host := importPath[:slash]
 	if !strings.Contains(host, ".") {