diff --git a/rules/provider/classical_strategy.go b/rules/provider/classical_strategy.go
index 1dbb82e6..95a772e8 100644
--- a/rules/provider/classical_strategy.go
+++ b/rules/provider/classical_strategy.go
@@ -96,7 +96,7 @@ func NewClassicalStrategy(parse func(tp, payload, target string, params []string
 	return &classicalStrategy{rules: []C.Rule{}, parse: func(tp, payload, target string, params []string) (parsed C.Rule, parseErr error) {
 		switch tp {
 		case "MATCH", "RULE-SET", "SUB-RULE":
-			return nil, fmt.Errorf("unsupported rule type on classical rule-set: (%s)", tp)
+			return nil, fmt.Errorf("unsupported rule type on classical rule-set: %s", tp)
 		default:
 			return parse(tp, payload, target, params, nil)
 		}