Formula One's new 2017 power unit agreement has a clause inserted in it to prevent teams and their engine suppliers from publicly denigrating each other, as Red Bull and Renault did last year.
The sport announced at last week's Russian Grand Prix a deal to ensure all teams have access to an engine supply, with prices cut over three years and performance gaps reduced.
An appendix to the 2017 sporting regulations, now published on the website of the governing International Automobile Federation, gives more details.
It says neither party shall take "any action and/or make any omission, deceptive, misleading or disparaging or negative comments, which directly injures, damages or brings into disrepute the public reputation, goodwill or favourable name or image of the other party to the supply agreement".
The website motorsport.com said one unidentified team principal had jokingly dubbed it the "Red Bull clause".
Red Bull and Renault won four successive drivers' and constructors' titles together between 2010 and 2013, but their relationship unravelled after the introduction of a new V6 turbo hybrid power unit in 2014 to replace the old V8s.
Mercedes were immediately established as the dominant force, while Renault's engine was both unreliable and down on performance.
As 2015 wore on, senior Red Bull management became increasingly vocal about what they saw as the engine's shortcomings, while searching for a more competitive alternative.
"Renault couldn't provide us with an engine that enabled us to run at the front.
It's that simple," Red Bull motorsport consultant Helmut Marko said in September.
When Mercedes and Ferrari ruled out a supply for 2016, and McLaren vetoed any move by Honda, Red Bull faced the threat of having no engine supplier.