We have noticed that the SOQL queries Agentforce Assistant builds, sometimes truncate the __c at the end of the custom fields' API names so it throws an error response. Recommendation is to add an agent instruction that specifies what to do with custom fields as a workaround but we are hoping it gets solved in the core product. We raised a ticket, but wanted to let the community know so you can apply the same workaround until its fixed 

#Agentforce  #Custom Fields