I was using this command to use a custom crafting table:

/execute @a ~ ~ ~ detect ~ ~-1 ~ dropper 1 {Items:[{id:minecraft:blaze_rod,Slot:1b,Count:1b,Damage:0s},{id:minecraft:blaze_rod,Slot:4b,Count:1b},{id:minecraft:stick,Slot:7b,Count:1b}]} /scoreboard players set @p LSC 1

But I get this error message when I stand on a dropper with these items:

Failed to execute '{Items:[{id:minecraft:blaze_rod,Slot:1b,Count:1b,Damage:0s},{id:minecraft:blaze_rod,Slot:4b,Count:1b},{id:minecraft:stick,Slot:7b,Count:1b}]} /scoreboard players set @p LSC 1' as TrevMCC38

By the way, Im in 16w06a

3 Answers 3


The detect function of /execute does not accept NBT data, only an ID and Damage value.

You will instead need to use /testforblock, and if needing multiplayer-friendliness, mixing it with CommandStats.


Objective to hold the CommandStats value.

/scoreboard objectives add CraftSuccess dummy

Applying the AffectedBlocks trigger to players, which will set the player's score based on the success of commands that specifically affect blocks, such as /testforblock. This may need to run on a clock in the event new players can join at any time.

/stats entity @a set AffectedBlocks @a[c=1] CraftSuccess

In order for CommandStats to modify a target's score, that target must be tracked on the scoreboard prior. This may also need to run on a clock for the same reason as before.

/scoreboard players add @a CraftSuccess 0


The following must be run in numerical order.

  1. Cause players to run the necessary /testforblock command.

    /execute @a ~ ~ ~ /testforblock ~ ~-1 ~ minecraft:dropper 1 {Items:[{id:"minecraft:blaze_rod",Slot:1b,Count:1b,Damage:0s},{id:"minecraft:blaze_rod",Slot:4b,Count:1b},{id:"minecraft:stick",Slot:7b,Count:1b}]}
  2. As a result, the executing player will have their own "CraftSuccess" score set equal to the number of blocks found by the /testforblock command. If the command failed, their score is set to 0. If the command succeeded, their score is set to 1. You'd then target players based on their score.

    /scoreboard players set @a[score_CraftSuccess_min=1] LSC 1

As a side-note, you should never mix @a as an executor and @p as the nested command's target if you're intended to target the same player. While @a can target dead players, @p cannot. That means that while the executor can run /execute while they're dead, they will not target themselves and instead target the nearest-living player. This can severely hurt accuracy and possibly break a target-sensitive mechanism.

The solution is to use the same selector when needed. For dead player targeting, you'd use @a as the executor with @a[c=1] as the nested selector:

/execute @a ~ ~ ~ /say @a[c=1]

For living-only players, you'd use @e[type=Player] with @p:

/execute @e[type=Player] ~ ~ ~ /say @p

It is also for this reason that CommandStat targets should use @a[c=1] when working with players, as this ensures there will not be an unintended target having their score modified.


Use comparators because they detect if something has blocks in it and sends a redstone signal.


No hacks are needed to test for blocks with NBT in Minecraft 1.13 and newer versions:

/execute as @a at @s if block ~ ~-1 ~ dropper{Items:[{id:"minecraft:blaze_rod",Slot:1b,Count:1b},{id:"minecraft:blaze_rod",Slot:4b,Count:1b},{id:"minecraft:stick",Slot:7b,Count:1b}]} run scoreboard players set @p LSC 1

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