The purpose of this article is to demonstrate that the introduction of legal definition of aggressive tax planning (ATP) together with anti-ATP rules by the European Commission under the Securing the Activity Framework of Enablers (SAFE) initiative is an example of legislative inflation of the anti-tax avoidance rules in the degradation phase of EU legal development in the area of direct taxation. The article aims to show that the legal use of ATP would add another factor for further disorder in an interpretation and application of existing concepts and anti-abusive rules in the EU law as well as triggers risk of over-reaction. The analysis of relevant contextual materials on the ATP will help to positively verify that hypothesis. The article will also lead to the conclusion that the Commission could propose new specific anti-avoidance rules (SAARs) based on the economic substance criteria in concert with references to activities that artificially exploit inconsistencies and mismatches between at least two systems of tax law without legally defining ATP. The introduction of such a new SAAR, however, is subject to two caveats. First, it would have to be placed within the boundaries of the rule of law, thereby causing only taxpayers engaging in international tax avoidance to suffer from uncertainty, i.e. the necessary degree of vagueness to effectively prevent tax avoidance by means of artificial exploitation of inconsistencies and mismatches between at least two systems of tax law. Second, proposing a new SAAR would be justified only insofar the Commission would present a robust analysis which confirms that recently introduced legislation against tax avoidance is not effective enough to target the mentioned exploitation. Otherwise, the inflation of anti-tax avoidance rules in the EU law would be guaranteed for the short-sighted benefit of politicians and at the cost of society and economy at large in the long term.