When attempting to add additional hammer recipes via any means (Either through KubeJS' scripts or datapack functionality, or other similar recipe altering mods), attempting to set the input item to a tag results in a non-functioning recipe on first start. The recipe is added and visible in JEI, but shows that the input is an empty tag with no blocks. This includes both modded tags (such as #forge:ores/iron) and vanilla tags (such as #minecraft:logs)

If the /reload command is issued, then the recipes are properly registered with populated tags and all the desired input blocks producing their configured outputs when hammered.

This behavior can be seen by pasting the following code into a .json file and placing it in the [MC instance]\kubejs\data\exdeorum\recipes\hammer folder (create the subfolders as needed):

{
  "type": "exdeorum:hammer",
  "ingredient": [
    {
      "tag": "minecraft:logs"
    }
  ],
  "result": "minecraft:stick",
  "result_amount": 16.0
}

When looking up hammer recipes in JEI, a recipe that outputs sticks will be visible with no valid inputs and logs will not break with a hammer any faster than with an empty fist, and will drop as a log when broken by a hammer.

Issue the /reload command and the recipe will be corrected, making logs breaks quickly with a hammer and producing a number of sticks when broken by a hammer.

Fixed in 1.9