diff --git a/src/kerberos/keygen/core.clj b/src/kerberos/keygen/core.clj
index 33782a9..5072a6f 100644
--- a/src/kerberos/keygen/core.clj
+++ b/src/kerberos/keygen/core.clj
@@ -25,7 +25,8 @@
 (defn -main [& args]
   (let [seed-string (str/join "" args)]
     (when (>= 32 (count seed-string))
-      (throw (ex-info "key generation requires a seed string of >32 characters." {})))
+      (throw (ex-info "key generation requires a seed string of >= 32 characters."
+                      { :seed-length (count seed-string)})))
     (-> seed-string
         (string->seed)
         (generate-key)