Actions

This page documents all available actions for the timeline.

Block Actions

place

Places a single block.

{
  "at": 0,
  "do": "place",
  "pos": [5, 1, 5],
  "block": {
    "id": "minecraft:lever",
    "powered": false,
    "face": "floor"
  }
}

Field	Type	Description
pos	[x, y, z]	Block position
block	object	Block with ID and properties

placeEach

Places multiple blocks atomically in the same tick. Ideal for setup phases.

{
  "at": 0,
  "do": "placeEach",
  "blocks": [
    { "pos": [0, 0, 0], "block": { "id": "minecraft:stone" } },
    { "pos": [1, 0, 0], "block": { "id": "minecraft:dirt" } },
    { "pos": [2, 0, 0], "block": { "id": "minecraft:grass_block" } }
  ]
}

Field	Type	Description
blocks	array	List of block placements
blocks[].pos	[x, y, z]	Position
blocks[].block	object	Block definition

When to use placeEach:

• Initial block placement at tick 0
• When multiple blocks must exist simultaneously
• For atomic operations (all or nothing)

fill

Fills a region with a block type.

{
  "at": 0,
  "do": "fill",
  "region": [[0, 0, 0], [10, 0, 10]],
  "with": { "id": "minecraft:stone" }
}

Field	Type	Description
region	[[x1,y1,z1], [x2,y2,z2]]	Area to fill
with	object	Block definition

Note: Coordinates can be swapped - Flint automatically determines min/max.

remove

Removes a block (replaces with air).

{
  "at": 5,
  "do": "remove",
  "pos": [5, 1, 5]
}

Field	Type	Description
pos	[x, y, z]	Position of block to remove

Player Actions

useItemOn

Uses an item on a block face. This triggers the server’s interaction logic.

Simple Mode - Item is specified directly:

{
  "at": 5,
  "do": "useItemOn",
  "pos": [3, 1, 3],
  "face": "top",
  "item": "minecraft:honeycomb"
}

Advanced Mode - Uses the player’s current held item:

{
  "at": 5,
  "do": "useItemOn",
  "pos": [3, 1, 3],
  "face": "north"
}

Field	Type	Required	Description
pos	[x, y, z]	Yes	Block position
face	string	Yes	Block face
item	string	No	Item for simple mode

Block Faces:

Face	Direction
top	+Y (above)
bottom	-Y (below)
north	-Z
south	+Z
east	+X
west	-X

setSlot

Sets an item in a player slot.

{
  "at": 3,
  "do": "setSlot",
  "slot": "hotbar1",
  "item": "minecraft:diamond_pickaxe",
  "count": 1
}

To clear a slot:

{
  "at": 3,
  "do": "setSlot",
  "slot": "hotbar1"
}

Field	Type	Required	Description
slot	string	Yes	Slot name
item	string	No	Item ID (empty = clear slot)
count	number	No	Amount (default: 1)

selectHotbar

Selects a hotbar slot (1-9).

{
  "at": 4,
  "do": "selectHotbar",
  "slot": 2
}

Field	Type	Description
slot	number	Hotbar slot (1-9)

Assertion Actions

assert

Verifies block states at specified positions.

{
  "at": 10,
  "do": "assert",
  "checks": [
    {
      "pos": [5, 1, 5],
      "is": {
        "id": "minecraft:redstone_wire",
        "power": 15,
        "north": "side"
      }
    },
    {
      "pos": [6, 1, 5],
      "is": { "id": "minecraft:air" }
    }
  ]
}

Field	Type	Description
checks	array	List of checks
checks[].pos	[x, y, z]	Position
checks[].is	object	Expected block

Behavior:

• Block ID is checked (with or without minecraft: prefix)
• Only specified properties are checked
• Unspecified properties are ignored
• On failure, the test stops immediately

Timing Examples

Sequential Actions

{
  "timeline": [
    { "at": 0, "do": "place", "pos": [0,0,0], "block": {"id": "minecraft:sand"} },
    { "at": 1, "do": "remove", "pos": [0,-1,0] },
    { "at": 5, "do": "assert", "checks": [
      { "pos": [0,0,0], "is": {"id": "minecraft:air"} },
      { "pos": [0,-1,0], "is": {"id": "minecraft:sand"} }
    ]}
  ]
}

Repeated Assertions

{
  "at": [10, 20, 30, 40, 50],
  "do": "assert",
  "checks": [
    { "pos": [5, 1, 5], "is": { "id": "minecraft:redstone_lamp", "lit": true } }
  ]
}

Timing for Redstone Components

Component	Delay (game ticks)
Redstone wire	0 (instant)
Repeater (1 tick)	2
Repeater (4 ticks)	8
Comparator	2
Observer	2