Command Data

From Minecraft 1.13, the Command Graph data structure defines commands which can be used in chat or in command blocks, and how they're parsed.

Graph Structure

The graph consists of nodes of type root, literal and argument. A node may point to a number child nodes, or redirect to another node, or neither. The root node is nameless, and its children are literal nodes for familiar commands ("msg", "me", etc).

Nodes are marked as executable if the node stack to this point constitutes a valid command. E.g. this is false for /ban but true for /ban Dinnerbone and /ban Dinnerbone created this crazy format.

When including redirects, this structure is a directed graph that may include cycles (e.g. consider /execute run execute run execute ...). When excluding redirects, the structure no longer contains cycles but may still not be a tree, as a node may have multiple parents.

Node Format

Field Name	Field Type	Notes
Flags	Byte	See below.
Children count	VarInt	Number of elements in the following array.
Children	Array of VarInt	Array of indices of child nodes.
Redirect node	Optional VarInt	Only if flags & 0x08. Index of redirect node.
Name	Optional String (32767)	Only for argument and literal nodes.
Parser	Optional Identifier	Only for argument nodes.
Properties	Optional Varies	Only for argument nodes. Varies by parser.
Suggestions type	Optional Identifier	Only if flags & 0x10.

Flags

Bit mask	Field Name	Notes
0x03	Node type	0: root, 1: literal, 2: argument. 3 is not used.
0x04	Is executable	Set if the node stack to this point constitutes a valid command.
0x08	Has redirect	Set if the node redirects to another node.
0x10	Has suggestions type	Only present for argument nodes.

Parsers

Clients are expected to implement all parsers, including properties (if any). If an unknown parser is encountered by a client, unpacking of the Declare Commands packet should stop immediately, as the structure of the remainder of the packet cannot be guessed.

Identifier	Properties	Description
brigadier:bool		Boolean value (true or false, case-sensitive)
brigadier:double	See below	Double
brigadier:float	See below	Float
brigadier:integer	See below	Integer
brigadier:string	See below	A string
minecraft:entity	See below	A selector, player name, or UUID.
minecraft:game_profile		A player, online or not. Can also use a selector, which may match one or more players (but not entities).
minecraft:block_pos		A location, represented as 3 numbers (which must be integers). May use relative locations with ~.
minecraft:column_pos		A column location, represented as 3 numbers (which must be integers). May use relative locations with ~.
minecraft:vec3		A location, represented as 3 numbers (which may have a decimal point, but will be moved to the center of a block if none is specified). May use relative locations with ~.
minecraft:vec2		A location, represented as 2 numbers (which may have a decimal point, but will be moved to the center of a block if none is specified). May use relative locations with ~.
minecraft:block_state		A block state, optionally including NBT and state information.
minecraft:block_predicate		A block, or a block tag.
minecraft:item_stack		An item, optionally including NBT.
minecraft:item_predicate		An item, or an item tag.
minecraft:color		A chat color. One of the names from Chat#Colors, or reset. Case-insensitive.
minecraft:component		A JSON Chat component.
minecraft:message		A regular message, potentially including selectors.
minecraft:nbt		An NBT value, parsed using JSON-NBT rules.
minecraft:nbt_path		A path within an NBT value, allowing for array and member accesses.
minecraft:objective		A scoreboard objective.
minecraft:objective_criteria		A single score criterion.
minecraft:operation		A scoreboard operator.
minecraft:particle		A particle effect (an identifier with extra information following it for specific particles, mirroring the Particle packet)
minecraft:rotation		An angle, represented as 2 numbers (which may have a decimal point, but will be moved to the center of a block if none is specified). May use relative locations with ~.
minecraft:scoreboard_slot		A scoreboard display position slot. list, sidebar, belowName, and sidebar.team.${color} for all chat colors (reset is not included)
minecraft:score_holder	See below	Something that can join a team. Allows selectors and *.
minecraft:swizzle		A collection of up to 3 axes.
minecraft:team		The name of a team. Parsed as an unquoted string.
minecraft:item_slot		A name for an inventory slot.
minecraft:resource_location		An Identifier.
minecraft:mob_effect		A potion effect.
minecraft:function		A function.
minecraft:entity_anchor		The entity anchor related to the facing argument in the teleport command, is feet or eyes.
minecraft:range	See below	A range of values with a min and a max.
minecraft:int_range		An integer range of values with a min and a max.
minecraft:float_range		A floating-point range of values with a min and a max.
minecraft:item_enchantment		Represents a item enchantment.
minecraft:entity_summon		Represents an entity summon.
minecraft:dimension		Represents a dimension.

Properties

brigadier:double

Specifies min and max values.

Name	Type	Description
Flags	Byte
Min	Optional double	Only if flags & 0x01. If not specified, defaults to -Double.MAX_VALUE (≈ -1.7976931348623157E307)
Max	Optional double	Only if flags & 0x02. If not specified, defaults to Double.MAX_VALUE (≈ 1.7976931348623157E307)

brigadier:float

Specifies min and max values.

Name	Type	Description
Flags	Byte
Min	Optional float	Only if flags & 0x01. If not specified, defaults to -Float.MAX_VALUE (≈ 3.4028235E38)
Max	Optional float	Only if flags & 0x02. If not specified, defaults to Float.MAX_VALUE (≈ 3.4028235E38)

brigadier:integer

Specifies min and max values.

Name	Type	Description
Flags	Byte
Min	Optional integer	Only if flags & 0x01. If not specified, defaults to Integer.MIN_VALUE (-2147483648)
Max	Optional integer	Only if flags & 0x02. If not specified, defaults to Integer.MAX_VALUE (2147483647)

brigadier:string

A VarInt enum.

Value	Name	Description
0	SINGLE_WORD	Reads a single word
1	QUOTABLE_PHRASE	If it starts with a ", keeps reading until another " (allowing escaping with \). Otherwise behaves the same as SINGLE_WORD
2	GREEDY_PHRASE	Reads the rest of the content after the cursor. Quotes will not be removed.

minecraft:entity

Has a single flags byte.

Bit mask	Meaning
0x01	If set, only allows a single entity/player
0x02	If set, only allows players

minecraft:score_holder

Has a single flags byte:

Bit mask	Meaning
0x01	If set, allows multiple.

minecraft:range

A range of values with a min and a max.

Name	Type	Description
Decimals	Boolean	Whether decimal values are allowed.

Suggestions Types

Identifier	Description
minecraft:ask_server	Sends the Tab-Complete packet to the server to request tab completions.
minecraft:all_recipes	Suggests all the available recipes.
minecraft:available_sounds	Suggests all the available sounds.
minecraft:summonable_entities	Suggests all the summonable entities.

Example Graphs

Command graph from 18w22c. Executable nodes are shown in green; redirects are dashed.