diff --git a/php/containers-schema.json b/php/containers-schema.json
index 1fceab26..b13da609 100644
--- a/php/containers-schema.json
+++ b/php/containers-schema.json
@@ -48,7 +48,10 @@
 						"type": "string"
 					},
 					"secrets": {
-						"type": "array"
+						"type": "array",
+						"items": {
+							"type": "string"
+						}
 					},
 					"volumes": {
 						"type": "array",