diff --git a/fs_edit_effects.lua b/fs_edit_effects.lua
index 2641d7d..1351ed8 100644
--- a/fs_edit_effects.lua
+++ b/fs_edit_effects.lua
@@ -57,9 +57,7 @@ local check_block = {
 	"- please select -", -- 1
 	"If there is air: Place a block so that it looks like now.", -- 2
 	"If there is a block: Dig it.", -- 3
-	-- TODO: not sure if punching a block (as an npc) is possible without bugs
 	"Punch the block.", -- 4
-	-- TODO: not sure if right-clicking a block (as an npc) is possible without bugs
 	"Right-click the block.", -- 5
 }
 
@@ -140,11 +138,32 @@ yl_speak_up.show_effect = function(r)
 				minetest.pos_to_string(r.r_pos)..": \""..tostring(r.r_value).."\"?"
 		end
 	elseif(r.r_type == "craft") then
+		-- this is only shown in the edit options menu and when editing an effect;
+		-- we can afford a bit of calculation here (it's not a precondtion...)
 		if(not(r.r_value) or not(r.r_craft_grid)) then
 			return "ERROR: Crafting not configured correctly."
 		end
-		-- TODO: check here if the craft receipe is broken?
-		return "Craft \""..tostring(r.r_value).."\" from "..table.concat(r.r_craft_grid, ", ").."."
+		local craft_str = "Craft \""..tostring(r.r_value).."\" from "..
+			table.concat(r.r_craft_grid, ", ").."."
+		-- check here if the craft receipe is broken
+		local input = {}
+		input.items = {}
+		for i, v in ipairs(r.r_craft_grid) do
+			input.items[ i ] = ItemStack(v or "")
+		end
+		input.method = "normal" -- normal crafting; no cooking or fuel or the like
+		input.width = 3
+		local output, decremented_input = minetest.get_craft_result(input)
+		if(output.item:is_empty()) then
+			return "Error: Recipe changed! No output for "..craft_str
+		end
+		-- the craft receipe may have changed in the meantime and yield a diffrent result
+		local expected_stack = ItemStack(r.r_value)
+		if(output.item:get_name() ~= expected_stack:get_name()
+		  or output.item:get_count() ~= expected_stack:get_count()) then
+			return "Error: Amount of output changed! "..craft_str
+		end
+		return craft_str
 	elseif(r.r_type == "on_failure") then
 		return "If the action (i.e. trade) failed, go to dialog \""..tostring(r.r_value).. "\"."
 	elseif(r.r_type == "chat_all") then
@@ -155,7 +174,8 @@ yl_speak_up.show_effect = function(r)
 end
 
 
--- called by yl_speak_up.input_talk(..); -- TODO
+-- called by yl_speak_up.input_talk(..)
+--
 -- This function is called *after* the player has clicked on an option
 -- and *after* any actions (i.e. trade) have been completed either
 -- successfully (=action_was_succesful is true) or not.
@@ -216,7 +236,7 @@ end
 
 -- executes an effect/result r for the player and npc n_id;
 -- returns true on success (relevant for on_failure)
--- TODO: in edit mode, nothing gets executed except perhaps dialog
+-- Note: In edit mode, this function does not get called.
 yl_speak_up.execute_effect = function(player, n_id, o_id, r)
 	if(not(r.r_type) or r.r_type == "") then
                 -- nothing to do
@@ -342,6 +362,8 @@ yl_speak_up.execute_effect = function(player, n_id, o_id, r)
 	-- "a block somewhere" -- 3
 	elseif(r.r_type == "block") then
 		-- TODO: implement effect "block"
+		-- TODO: not sure if punching a block (as an npc) is possible without bugs
+		-- TODO: not sure if right-clicking a block (as an npc) is possible without bugs
 	-- ""NPC crafts soemthing", -- 4
 	elseif(r.r_type == "craft") then
 		if(not(r.r_craft_grid) or not(r.r_value)) then