diff --git a/specs.json b/specs.json
index 00131dd..00561b0 100644
--- a/specs.json
+++ b/specs.json
@@ -659,6 +659,7 @@
       "label": "string",
       "language": "string",
       "voice": "string|object",
+      "model": "string",
       "fallbackVendor": "string",
       "fallbackLabel": "string",
       "fallbackLanguage": "string",
diff --git a/test/jambonz-verb-test.js b/test/jambonz-verb-test.js
index c2ac9fc..edb91c8 100644
--- a/test/jambonz-verb-test.js
+++ b/test/jambonz-verb-test.js
@@ -505,6 +505,15 @@ test("validate correct verbs", async (t) => {
         "language": "en-US"
       }
     },
+    {
+      "verb": "say",
+      "text": "hi there!",
+      "synthesizer" : {
+        "vendor": "google",
+        "language": "en-US",
+        "model": "gemini-2.5-flash-tts"
+      }
+    },
     {
       "verb": "sip:decline",
       "status": 480,