diff --git a/kernel/api/filetree.go b/kernel/api/filetree.go
index a8bb81b8a..cd02b1c94 100644
--- a/kernel/api/filetree.go
+++ b/kernel/api/filetree.go
@@ -114,11 +114,11 @@ func listDocTree(c *gin.Context) {
 
 	ids := map[string]bool{}
 	for _, entry := range dir {
-		if entry.IsDir() {
-			if strings.HasPrefix(entry.Name(), ".") {
-				continue
-			}
+		if strings.HasPrefix(entry.Name(), ".") {
+			continue
+		}
 
+		if entry.IsDir() {
 			if !ast.IsNodeIDPattern(entry.Name()) {
 				continue
 			}
@@ -134,7 +134,12 @@ func listDocTree(c *gin.Context) {
 				return
 			}
 		} else {
-			doc := &DocFile{ID: strings.TrimSuffix(entry.Name(), ".sy")}
+			id := strings.TrimSuffix(entry.Name(), ".sy")
+			if !ast.IsNodeIDPattern(id) {
+				continue
+			}
+
+			doc := &DocFile{ID: id}
 			if !ids[doc.ID] {
 				doctree = append(doctree, doc)
 			}