diff --git a/CHANGELOG.md b/CHANGELOG.md
index d57861f..75cff10 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,8 @@ change log follows the conventions of
 
 ### Changed
 
+- Report a proper error for an unknown model name (#100).
+
 ### Deprecated
 
 ### Fixed
diff --git a/src/elle_cli/cli.clj b/src/elle_cli/cli.clj
index 1a810de..ad01efe 100644
--- a/src/elle_cli/cli.clj
+++ b/src/elle_cli/cli.clj
@@ -93,9 +93,9 @@
   "tools.cli options"
 
    ; General options.
-  [["-m" "--model MODEL"
+  [   ["-m" "--model MODEL"
     "(General) A name of consistency model for checking."
-    :validate [identity
+    :validate [#(contains? models %)
                (str "Must be one of " (str/join ", " (sort (keys models))))]]
    ["-f" "--format FORMAT"
     "(General) Format of file with history. Either 'edn' or 'json'."