Almost every modern lunar practitioner will tell you not to set intentions during an eclipse, even though an eclipse is a new or full moon and those are the two days you normally would.

The stated reason is that eclipses bring events rather than choices, so anything begun then goes somewhere you did not plan. It is a genuinely old instinct dressed in new language — eclipses have been read as unlucky in Mesopotamian, Indian and Chinese traditions alike — and it is one of the rare cases where modern practice tells people to do less.