I cut very charif red peppers with a parev knife on a clean eino ben yomo glass dish.
What is the status of the knife?
The knife remains parev. Lechatchilah, a parev cutting board should be used.
Sources: See Chochmas Adam, Kelal 60; Tuv Taam Vedaas 3:216. Some are lenient, however (even for the food itself), applying the stringency of davar charif only to the direct pressure of a knife, and one may certainly be lenient for the knife, which would only involve a belia of taste from the pepper (which itself absorbed taste from eino ben yomo) , for which some are in any case lenient.