diff --git a/num_fd.go b/num_fd.go
index 9806802..ebe98bb 100644
--- a/num_fd.go
+++ b/num_fd.go
@@ -43,6 +43,8 @@ func countDir(dir string) int {
 	return len(names) - 1 // for the dir we just opened
 }
 
+// NumFD returns the number of open file descriptors (or -1 on error).
+// On windows it returns the number of handles.
 func NumFD() int {
 	switch runtime.GOOS {
 	case "windows":
diff --git a/scli.go b/scli.go
index e57e999..947f1c3 100644
--- a/scli.go
+++ b/scli.go
@@ -9,6 +9,8 @@
 // Configure using the [cli] package variables (at minimum [MinArgs] unless your
 // binary only accepts flags), setup additional [flag] before calling
 // [ServerMain].
+// It also includes [NumFD] utility function to cross platform get the number
+// of open file descriptors (handles on windows) held by your go process.
 package scli // import "fortio.org/scli"
 
 import (