# Annotation Interface Mutate

@Retention(RUNTIME) @Target(METHOD) @Incubating public @interface Mutate
Denotes that the `RuleSource` method rule carrying this annotation mutates the rule subject.

Mutate rules execute after `Defaults` rules, but before `Finalize` rules. The first parameter of the rule is the rule subject, which is mutable for the duration of the rule.

Please see `RuleSource` for more information on method rules.