diff --git a/src/Json.ml b/src/Json.ml
index b326ee7..a654a7d 100644
--- a/src/Json.ml
+++ b/src/Json.ml
@@ -49,7 +49,7 @@ module Of_json = struct
       if String.length s = 1 then String.get s 0
       else
         of_json_error
-          ("Expected a single-character string, got "
+          ("Expected single-character string, got "
           ^ Js.Json.stringify json)
     else of_json_error "expected a string"
 
diff --git a/src/__tests__/Json_decode_test.ml b/src/__tests__/Json_decode_test.ml
index b382084..649dd4a 100644
--- a/src/__tests__/Json_decode_test.ml
+++ b/src/__tests__/Json_decode_test.ml
@@ -118,7 +118,7 @@ let () =
             fail "should throw"
           with
           | Of_json_error
-              (Json_error "Expected a single-character string, got \"\"")
+              (Json_error "Expected single-character string, got \"\"")
           ->
             pass);
 
@@ -128,8 +128,7 @@ let () =
             fail "should throw"
           with
           | Of_json_error
-              (Json_error
-                 "Expected a single-character string, got \"abc\"")
+              (Json_error "Expected single-character string, got \"abc\"")
           ->
             pass);