diff --git a/README.md b/README.md
new file mode 100644
index 0000000..bb42e0b
--- /dev/null
+++ b/README.md
@@ -0,0 +1,5 @@
+# lambda-authorizer-client
+
+Lambda authorizer which validates JWT signature and claims. Specific to client ordering flow.
+
+Part of a group course project of a self service and kitchen management system for a fictional fast food restaurant.
diff --git a/index.js b/index.js
index 629a51c..52ad21d 100644
--- a/index.js
+++ b/index.js
@@ -29,14 +29,14 @@ exports.handler = async (event) => {
       jwtSettings.options
     );
 
-    if (decoded.sub == null) {
-      console.log('Missing sub claim');
+    if (!decoded.sub || !Number(decoded.sub)) {
+      console.log('Missing or invalid sub claim');
       return { isAuthorized: false };
     }
 
     return { isAuthorized: true };
   } catch (error) {
-    console.log('Token validation failed', token);
+    console.log('Token verification failed', token);
     return { isAuthorized: false };
   }
 };