Setting intentions before taking Ayahuasca during an Ayahuasca retreat or ceremony is a recurring theme, a task that many retreat facilitators, Shamans, or Curanderos will ask you to do and take seriously.
To formulate your intention (or intentions) belongs to the set of things you should do to optimally prepare yourself for the effects of drinking the Ayahuasca brew.
In fact, it’s generally thought that setting clear and proper intentions helps to have a “good trip” instead of a “bad trip,” and moreover helps you to engage in positive changes, spiritual growth, and healing, and getting the most out of your Ayahuasca experience.
Intentions — which you can see as aims or objectives — can also support you in (re)focusing your mind when you are under the influence of the Ayahuasca brew. It can help you know and understand why you might be “seeing things,” of which some may be unpleasant, and it can support you to stay “grounded” during an experience that gets you “flying.”
Another thing is that your intention will typically guide the experience. That is, the Master Teacher Plants — in this case Ayahuasca — will tend to give you answers to your questions, or insights in how to approach your questions in order to resolve them.
Mind that the kind of intentions you set should rather focus on the solution to a problem or challenge than on the problem or challenge itself.
So, for example, you may have joined an Ayahuasca retreat because you want to get rid of certain repetitive or structural fears in your life. Now, instead of saying “I want to get rid of my fears” (which could result in a hallucinatory magnification of your fears during the “trip”), the intention or question should rather be “What do I need to do, achieve, or change to get rid of my fears?”
In any case, apart from specific things you want to attain, you could also simply ask the Ayahuasca medicine to show you what it is you need to know or do to proceed in a positive way with your life.