The synthetic favorite currently only detects item stacks in player inventory, if an item is in Applied Energistics 2 or Refined Storage system (generally speaking, any crafting bench that includes a storage space), the synthetic favorite cannot detect whether the item exists or not, it informs player the ingredient is absent. This is inconvenient when crafting items with complex recipe.

I want EMI to be able to detect item in crafting workbench in an efficient way.
I think an API for third party mod maker to provide whether the required item is in the internal buffer of crafting bench might work?

P.S. Though I am not senior in writing Minecraft mod, I am willing to contribute to either EMI or AE2 for this feature.

This API exists, if mods are not exposing their inventories, it's for performance concerns or lack of integration.

It looks like for AE2 they want more features in the API, specifically refreshing the list of craftables in order to make the performance better.
AppliedEnergistics/Applied-Energistics-2#8074