Difference between revisions of "Pre-release protocol"

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(Entity Equipment is clientbound)
(Declare Recipes had smithing added)
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{{PacketList|{{change|0x59|0x58}}|Entity Properties}}
 
{{PacketList|{{change|0x59|0x58}}|Entity Properties}}
 
{{PacketList|{{change|0x5A|0x59}}|Entity Effect|pre=unchanged}}
 
{{PacketList|{{change|0x5A|0x59}}|Entity Effect|pre=unchanged}}
−
{{PacketList|{{change|0x5B|0x5A}}|Declare Recipes|pre=unchanged}}
+
{{PacketList|{{change|0x5B|0x5A}}|Declare Recipes}}
 
{{PacketList|{{change|0x5C|0x5B}}|Tags|pre=unchanged}}
 
{{PacketList|{{change|0x5C|0x5B}}|Tags|pre=unchanged}}
 
  |-
 
  |-
Line 951: Line 951:
  
 
All of the 0's are applied first, and then the 1's, and then the 2's.
 
All of the 0's are applied first, and then the 1's, and then the 2's.
 +
 +
==== Declare Recipes ====
 +
 +
{| class="wikitable"
 +
! Packet ID
 +
! State
 +
! Bound To
 +
!colspan="2"| Field Name
 +
!colspan="2"| Field Type
 +
! Notes
 +
|-
 +
|rowspan="4"| {{change|0x5B|0x5A}}
 +
|rowspan="4"| Play
 +
|rowspan="4"| Client
 +
|colspan="2"| Num Recipes
 +
|colspan="2"| VarInt
 +
| Number of elements in the following array
 +
|-
 +
|rowspan="3"| Recipe
 +
| Recipe ID
 +
|rowspan="3"| Array
 +
| Identifier
 +
|
 +
|-
 +
| Type
 +
| String
 +
| The recipe type, see below
 +
|-
 +
| Data
 +
| Optional, varies
 +
| Additional data for the recipe.  For some types, there will be no data.
 +
|}
 +
 +
Recipe types:
 +
 +
{| class="wikitable"
 +
! Type
 +
! Description
 +
! Data
 +
|-
 +
| <code>crafting_shapeless</code>
 +
| Shapeless crafting recipe.  All items in the ingredient list must be present, but in any order/slot.
 +
| As follows:
 +
  {| class="wikitable"
 +
    ! Name
 +
    ! Type
 +
    ! Description
 +
    |-
 +
    | Group
 +
    | String
 +
    | Used to group similar recipes together in the recipe book.  Tag is present in recipe JSON.
 +
    |-
 +
    | Ingredient count
 +
    | VarInt
 +
    | Number of elements in the following array
 +
    |-
 +
    | Ingredients
 +
    | Array of Ingredient
 +
    |
 +
    |-
 +
    | Result
 +
    | [[Slot]]
 +
    |
 +
    |}
 +
|-
 +
| <code>crafting_shaped</code>
 +
| Shaped crafting recipe.  All items must be present in the same pattern (which may be flipped horizontally or translated)
 +
| As follows:
 +
  {| class="wikitable"
 +
    ! Name
 +
    ! Type
 +
    ! Description
 +
    |-
 +
    | Width
 +
    | VarInt
 +
    |
 +
    |-
 +
    | Height
 +
    | VarInt
 +
    |
 +
    |-
 +
    | Group
 +
    | String
 +
    | Used to group similar recipes together in the recipe book.  Tag is present in recipe JSON.
 +
    |-
 +
    | Ingredients
 +
    | Array of Ingredient
 +
    | Length is width * height.  Indexed by x + (y * width).
 +
    |-
 +
    | Result
 +
    | [[Slot]]
 +
    |
 +
    |}
 +
|-
 +
| <code>crafting_special_armordye</code>
 +
| Recipe for dying leather armor
 +
|rowspan="13"| None
 +
|-
 +
| <code>crafting_special_bookcloning</code>
 +
| Recipe for copying contents of written books
 +
|-
 +
| <code>crafting_special_mapcloning</code>
 +
| Recipe for copying maps
 +
|-
 +
| <code>crafting_special_mapextending</code>
 +
| Recipe for adding paper to maps
 +
|-
 +
| <code>crafting_special_firework_rocket</code>
 +
| Recipe for making firework rockets
 +
|-
 +
| <code>crafting_special_firework_star</code>
 +
| Recipe for making firework stars
 +
|-
 +
| <code>crafting_special_firework_star_fade</code>
 +
| Recipe for making firework stars fade between multiple colors
 +
|-
 +
| <code>crafting_special_repairitem</code>
 +
| Recipe for repairing items via crafting
 +
|-
 +
| <code>crafting_special_tippedarrow</code>
 +
| Recipe for crafting tipped arrows
 +
|-
 +
| <code>crafting_special_bannerduplicate</code>
 +
| Recipe for copying banner patterns
 +
|-
 +
| <code>crafting_special_banneraddpattern</code>
 +
| Recipe for adding patterns to banners
 +
|-
 +
| <code>crafting_special_shielddecoration</code>
 +
| Recipe for applying a banner's pattern to a shield
 +
|-
 +
| <code>crafting_special_shulkerboxcoloring</code>
 +
| Recipe for recoloring a shulker box
 +
|-
 +
| <code>smelting</code>
 +
| Smelting recipe
 +
|rowspan="4"| As follows:
 +
  {| class="wikitable"
 +
    ! Name
 +
    ! Type
 +
    ! Description
 +
    |-
 +
    | Group
 +
    | String
 +
    | Used to group similar recipes together in the recipe book.
 +
    |-
 +
    | Ingredient
 +
    | Ingredient
 +
    |
 +
    |-
 +
    | Result
 +
    | [[Slot]]
 +
    |
 +
    |-
 +
    | Experience
 +
    | Float
 +
    |
 +
    |-
 +
    | Cooking time
 +
    | VarInt
 +
    |
 +
    |}
 +
|-
 +
| <code>blasting</code>
 +
| Blast furnace recipe
 +
|-
 +
| <code>smoking</code>
 +
| Smoker recipe
 +
|-
 +
| <code>campfire_cooking</code>
 +
| Campfire recipe
 +
|-
 +
| <code>stonecutting</code>
 +
| Stonecutter recipe
 +
| As follows:
 +
  {| class="wikitable"
 +
    ! Name
 +
    ! Type
 +
    ! Description
 +
    |-
 +
    | Group
 +
    | String
 +
    | Used to group similar recipes together in the recipe book.  Tag is present in recipe JSON.
 +
    |-
 +
    | Ingredient
 +
    | Ingredient
 +
    |
 +
    |-
 +
    | Result
 +
    | [[Slot]]
 +
    |
 +
    |}
 +
|- {{Added}}
 +
| <code>smithing</code>
 +
| Smithing table recipe
 +
| As follows:
 +
  {| class="wikitable"
 +
    ! Name
 +
    ! Type
 +
    ! Description
 +
    |-
 +
    | Base
 +
    | Ingredient
 +
    | First item
 +
    |-
 +
    | Addition
 +
    | Ingredient
 +
    | Second item
 +
    |-
 +
    | Result
 +
    | [[Slot]]
 +
    |
 +
    |}
 +
|}
 +
 +
Ingredient is defined as:
 +
 +
{| class="wikitable"
 +
! Name
 +
! Type
 +
! Description
 +
|-
 +
| Count
 +
| VarInt
 +
| Number of elements in the following array
 +
|-
 +
| Items
 +
| Array of [[Slot]]
 +
| Any item in this array may be used for the recipe.  The count of each item should be 1.
 +
|}
  
 
=== Serverbound ===
 
=== Serverbound ===

Revision as of 03:05, 23 June 2020

This page documents the changes from the last stable Minecraft release (currently 1.15.2, protocol 578) to the current pre-release (currently 1.16-rc1, protocol 734). Note that this page contains bleeding-edge information that may not be completely or correctly documented.

One who wishes to commandeer the merging of this into Protocol when an update is made must be sure to respect any changes that may have occurred to the respective packets there.

Contents

Data types

The UUID type is now also sometimes encoded by the Notchian server as an array of four 32-bit integers, from most significant to least significant (matching the new format used on entity NBT). This representation is identical to using 16 bytes, two 64-bit integers, or one 128-bit integers.

Packets

ID Packet name Documentation
Handshaking serverbound
0x00 Handshake Current Pre
Play clientbound
0x02 Spawn Weather Entity Current
0x03 0x02 Spawn Living Entity Current (unchanged)
0x04 0x03 Spawn Painting Current (unchanged)
0x05 0x04 Spawn Player Current (unchanged)
0x06 0x05 Entity Animation (clientbound) Current (unchanged)
0x07 0x06 Statistics Current (unchanged)
0x08 0x07 Acknowledge Player Digging Current (unchanged)
0x09 0x08 Block Break Animation Current (unchanged)
0x0A 0x09 Block Entity Data Current (unchanged)
0x0B 0x0A Block Action Current (unchanged)
0x0C 0x0B Block Change Current (unchanged)
0x0D 0x0C Boss Bar Current (unchanged)
0x0E 0x0D Server Difficulty Current (unchanged)
0x0F 0x0E Chat Message (clientbound) Current Pre
0x10 0x0F Multi Block Change Current (unchanged)
0x11 0x10 Tab-Complete (clientbound) Current (unchanged)
0x12 0x11 Declare Commands Current (unchanged)
0x13 0x12 Window Confirmation (clientbound) Current (unchanged)
0x14 0x13 Close Window (clientbound) Current (unchanged)
0x15 0x14 Window Items Current (unchanged)
0x16 0x15 Window Property Current (unchanged)
0x17 0x16 Set Slot Current (unchanged)
0x18 0x17 Set Cooldown Current (unchanged)
0x19 0x18 Plugin Message (clientbound) Current (unchanged)
0x1A 0x19 Named Sound Effect Current (unchanged)
0x1B 0x1A Disconnect (play) Current (unchanged)
0x1C 0x1B Entity Status Current (unchanged)
0x1D 0x1C Explosion Current (unchanged)
0x1E 0x1D Unload Chunk Current (unchanged)
0x1F 0x1E Change Game State Current (unchanged)
0x20 0x1F Open Horse Window Current (unchanged)
0x21 0x20 Keep Alive (clientbound) Current (unchanged)
0x22 0x21 Chunk Data Current Pre
0x23 0x22 Effect Current (unchanged)
0x24 0x23 Particle Current (unchanged)
0x25 0x24 Update Light Current Pre
0x26 0x25 Join Game Current Pre
0x27 0x26 Map Data Current (unchanged)
0x28 0x27 Trade List Current (unchanged)
0x29 0x28 Entity Position Current (unchanged)
0x2A 0x29 Entity Position and Rotation Current (unchanged)
0x2B 0x2A Entity Rotation Current (unchanged)
0x2C 0x2B Entity Movement Current (unchanged)
0x2D 0x2C Vehicle Move (clientbound) Current (unchanged)
0x2E 0x2D Open Book Current (unchanged)
0x2F 0x2E Open Window Current (unchanged)
0x30 0x2F Open Sign Editor Current (unchanged)
0x31 0x30 Craft Recipe Response Current (unchanged)
0x32 0x31 Player Abilities (clientbound) Current (unchanged)
0x33 0x32 Combat Event Current (unchanged)
0x34 0x33 Player Info Current (unchanged)
0x35 0x34 Face Player Current (unchanged)
0x36 0x35 Player Position And Look (clientbound) Current (unchanged)
0x37 0x36 Unlock Recipes Current (unchanged)
0x38 0x37 Destroy Entities Current (unchanged)
0x39 0x38 Remove Entity Effect Current (unchanged)
0x3A 0x39 Resource Pack Send Current (unchanged)
0x3B 0x3A Respawn Current Pre
0x3C 0x3B Entity Head Look Current (unchanged)
0x3D 0x3C Select Advancement Tab Current (unchanged)
0x3E 0x3D World Border Current (unchanged)
0x3F 0x3E Camera Current (unchanged)
0x40 0x3F Held Item Change (clientbound) Current (unchanged)
0x41 0x40 Update View Position Current (unchanged)
0x42 0x41 Update View Distance Current (unchanged)
0x47 Entity Equipment Current Pre
0x4E 0x42 Spawn Position Current (unchanged)
0x4F 0x4E Time Update Current (unchanged)
0x50 0x4F Title Current (unchanged)
0x51 0x50 Entity Sound Effect Current (unchanged)
0x52 0x51 Sound Effect Current (unchanged)
0x53 0x52 Stop Sound Current (unchanged)
0x54 0x53 Player List Header And Footer Current (unchanged)
0x55 0x54 NBT Query Response Current (unchanged)
0x56 0x55 Collect Item Current (unchanged)
0x57 0x56 Entity Teleport Current (unchanged)
0x58 0x57 Advancements Current (unchanged)
0x59 0x58 Entity Properties Current Pre
0x5A 0x59 Entity Effect Current (unchanged)
0x5B 0x5A Declare Recipes Current Pre
0x5C 0x5B Tags Current (unchanged)
Play serverbound
0x0E Interact Entity Current Pre
0x0F Generate Structure Pre
0x0F 0x10 Keep Alive (serverbound) Current (unchanged)
0x10 0x11 Lock Difficulty Current (unchanged)
0x11 0x12 Player Position Current (unchanged)
0x12 0x13 Player Position And Rotation (serverbound) Current (unchanged)
0x13 0x14 Player Rotation Current (unchanged)
0x14 0x15 Player Movement Current (unchanged)
0x15 0x16 Vehicle Move (serverbound) Current (unchanged)
0x16 0x17 Steer Boat Current (unchanged)
0x17 0x18 Pick Item Current (unchanged)
0x18 0x19 Craft Recipe Request Current (unchanged)
0x19 0x1A Player Abilities (serverbound) Current Pre
0x1A 0x1B Player Digging Current (unchanged)
0x1B 0x1C Entity Action Current (unchanged)
0x1C 0x1D Steer Vehicle Current (unchanged)
0x1D 0x1E Recipe Book Data Current (unchanged)
0x1E 0x1F Name Item Current (unchanged)
0x1F 0x20 Resource Pack Status Current (unchanged)
0x20 0x21 Advancement Tab Current (unchanged)
0x21 0x22 Select Trade Current (unchanged)
0x22 0x23 Set Beacon Effect Current (unchanged)
0x23 0x24 Held Item Change (serverbound) Current (unchanged)
0x24 0x25 Update Command Block Current (unchanged)
0x25 0x26 Update Command Block Minecart Current (unchanged)
0x26 0x27 Creative Inventory Action Current (unchanged)
0x27 0x28 Update Jigsaw Block Current Pre
0x28 0x29 Update Structure Block Current (unchanged)
0x29 0x2A Update Sign Current (unchanged)
0x2A 0x2B Animation (serverbound) Current (unchanged)
0x2B 0x2C Spectate Current (unchanged)
0x2C 0x2D Player Block Placement Current (unchanged)
0x2D 0x2E Use Item Current (unchanged)
Login clientbound
0x02 Login Success Current Pre

New/modified data types

No changes so far.

Entity Metadata

FishingHook

Extends Entity.

Index Type Meaning Default
7 VarInt Hooked entity id + 1, or 0 if there is no hooked entity 0
8 Boolean Is catchable False

Abstract Arrow

Extends Entity.

Abstract base class for Tipped Arrow (which is used for regular arrows as well as tipped ones) and Spectral Arrow.

Index Type Meaning Default
7 Byte Bit mask Meaning 0
0x01 Is critical
0x02 Is noclip (used by loyalty tridents when returning)
8 OptUUID Unused Empty
9 8 Byte Peircing level 0

Tipped Arrow

Extends Abstract Arrow.

Used for both tipped and regular arrows. If not tipped, then color is set to -1 and no tipped arrow particles are used.

Index Type Meaning Default
10 9 VarInt Color (-1 for no particles) -1

Spectral Arrow

Extends Abstract Arrow.

No additional metadata.

Trident

Extends Abstract Arrow.

Index Type Meaning Default
10 9 VarInt Loyalty level (enchantment) 0
11 10 Boolean Has enchantment glint False

Strider

Extends Animal.

Index Type Meaning Default
16 VarInt Total time to "boost" with warped fungus on a stick for 0
17 Boolean Should display name tag (true unless riding a vehicle or on or in a block tagged with strider_warm_blocks (default: lava)) false
18 Boolean Has saddle false

Hoglin

Extends Animal.

Index Type Meaning Default
16 Boolean Is immune to zombification false

Zoglin

Extends Monster.

Index Type Meaning Default
15 Boolean Is baby false

Piglin

Extends Monster.

Index Type Meaning Default
15 Boolean Is baby false
16 Boolean Is immune to zombification false
17 Boolean Is charging crossbow false
18 Boolean Is dancing false

Wolf

Extends TameableAnimal.

Index Type Meaning Default
18 Boolean Is begging false
19 VarInt Collar color (values are those used with dyes) 14 (Red)
20 VarInt Anger time 0


Zombie Pigman Zombified Piglin

Extends Zombie.

No additional metadata.

Block Actions

No changes so far.

Inventories

No changes so far.

Plugin Channels

No changes so far.

Play

Clientbound

Chat Message (clientbound)

Identifying the difference between Chat/System Message is important as it helps respect the user's chat visibility options. See processing chat for more info about these positions.

Warning.png Game info accepts json formatting but does not display it, although the deprecated §-based formatting works. This is not an issue when using the Title packet, so prefer that packet for displaying information in that slot. See MC-119145 for more information.

Packet ID State Bound To Field Name Field Type Notes
0x0F 0x0E Play Client JSON Data Chat Limited to 32767 bytes
Position Byte 0: chat (chat box), 1: system message (chat box), 2: game info (above hotbar).
Sender UUID Used by the Notchian client for the disableChat launch option. Setting both longs to 0 will always display the message regardless of the setting.

Chunk Data

Main article: Chunk Format
See also: #Unload Chunk
Huh.png The following information needs to be added to this page:
How do biomes work now? The biome change happened at the same time as the seed change, but it's not clear how/if biomes could be computed given that it's not the actual seed... (/r/mojira discussion which notes that it seems to be some kind of interpolation, and 3D biomes are only used in the nether)

The server only sends skylight information for chunk pillars in the Overworld, it's up to the client to know in which dimenison the player is currently located. You can also infer this information from the primary bitmask and the amount of uncompressed bytes sent. This packet also sends all block entities in the chunk (though sending them is not required; it is still legal to send them with Update Block Entity later).

Packet ID State Bound To Field Name Field Type Notes
0x22 0x21 Play Client Chunk X Int Chunk coordinate (block coordinate divided by 16, rounded down)
Chunk Z Int Chunk coordinate (block coordinate divided by 16, rounded down)
Full chunk Boolean See Chunk Format
Ignore old data Boolean If false, the client will recalculate lighting based on the old/new chunk data
Primary Bit Mask VarInt Bitmask with bits set to 1 for every 16×16×16 chunk section whose data is included in Data. The least significant bit represents the chunk section at the bottom of the chunk column (from y=0 to y=15).
Heightmaps NBT Compound containing one long array named MOTION_BLOCKING, which is a heightmap for the highest solid block at each position in the chunk (as a compacted long array with 256 entries at 9 bits per entry totaling 36 longs). The Notchian server also adds a WORLD_SURFACE long array, the purpose of which is unknown, but it's not required for the chunk to be accepted.
Biomes Optional array of Integer 1024 biome IDs, ordered by x then z then y, in 4×4×4 blocks. Not present if full chunk is false.
Size VarInt Size of Data in bytes
Data Byte array See data structure in Chunk Format
Number of block entities VarInt Number of elements in the following array
Block entities Array of NBT Tag All block entities in the chunk. Use the x, y, and z tags in the NBT to determine their positions.

Note that the Notchian client requires an Update View Position packet when it crosses a chunk border, otherwise it'll only display render distance + 2 chunks around the chunk it spawned in.

The compacted array format has been adjusted so that individual entries no longer span across multiple longs, affecting the main data array and heightmaps.

Update Light

Updates light levels for a chunk.

Packet ID State Bound To Field Name Field Type Notes
0x25 0x24 Play Client Chunk X VarInt Chunk coordinate (block coordinate divided by 16, rounded down)
Chunk Z VarInt Chunk coordinate (block coordinate divided by 16, rounded down)
Trust Edges Boolean If edges should be trusted for light updates.
Sky Light Mask VarInt Mask containing 18 bits, with the lowest bit corresponding to chunk section -1 (in the void, y=-16 to y=-1) and the highest bit for chunk section 16 (above the world, y=256 to y=271)
Block Light Mask VarInt Mask containing 18 bits, with the same order as sky light
Empty Sky Light Mask VarInt Mask containing 18 bits, which indicates sections that have 0 for all their sky light values. If a section is set in both this mask and the main sky light mask, it is ignored for this mask and it is included in the sky light arrays (the notchian server does not create such masks). If it is only set in this mask, it is not included in the sky light arrays.
Empty Block Light Mask VarInt Mask containing 18 bits, which indicates sections that have 0 for all their block light values. If a section is set in both this mask and the main block light mask, it is ignored for this mask and it is included in the block light arrays (the notchian server does not create such masks). If it is only set in this mask, it is not included in the block light arrays.
Sky Light arrays Length Array VarInt Length of the following array in bytes (always 2048)
Sky Light array Array of 2048 bytes There is 1 array for each bit set to true in the sky light mask, starting with the lowest value. Half a byte per light value.
Block Light arrays Length Array VarInt Length of the following array in bytes (always 2048)
Block Light array Array of 2048 bytes There is 1 array for each bit set to true in the block light mask, starting with the lowest value. Half a byte per light value.

Individual block or sky light arrays are is given for each block with increasing x coordinates, within rows of increasing z coordinates, within layers of increasing y coordinates. Even-indexed items (those with an even x coordinate, starting at 0) are packed into the low bits, odd-indexed into the high bits.

Join Game

See Protocol Encryption for information on logging in.

Packet ID State Bound To Field Name Field Type Notes
0x26 0x25 Play Client Entity ID Int The player's Entity ID (EID)
Gamemode Unsigned Byte 0: Survival, 1: Creative, 2: Adventure, 3: Spectator. Bit 3 (0x8) is the hardcore flag.
Previous Gamemode Unsigned Byte 0: survival, 1: creative, 2: adventure, 3: spectator. The hardcore flag is not included. The previous gamemode. (More information needed)
World Count VarInt Size of the following array
World Names Array of Identifier Identifiers for all worlds on the server
Dimension Codec NBT Tag Compound This CompoundTag contains a ListTag named "dimension". The ListTag should contain CompoundTags with named StringTags "key" and "element". The full extent of these is still unknown, but the tag represents a dimension registry. See below for the vanilla default.
Dimension Int Enum Identifier -1: The Nether, 0: The Overworld, 1: The End Valid dimensions are defined per dimension registry sent before this
World Name Identifier Name of the world being spawned into
Hashed seed Long First 8 bytes of the SHA-256 hash of the world's seed.
Max Players Unsigned Byte Was once used by the client to draw the player list, but now is ignored
Level Type String Enum (16) default, flat, largeBiomes, amplified, customized, buffet, default_1_1
View Distance VarInt Render distance (2-32)
Reduced Debug Info Boolean If true, a Notchian client shows reduced information on the debug screen. For servers in development, this should almost always be false.
Enable respawn screen Boolean Set to false when the doImmediateRespawn gamerule is true
Is Debug Boolean True if the world is a debug mode world; debug mode worlds cannot be modified and have predefined blocks
Is Flat Boolean True if the world is a superflat world; flat worlds have different void fog and a horizon at y=0 instead of y=63

Example of Dimension codec CompoundTag sent by the server: 

   ListTag (Type: CompoundTag) "dimension":
       CompoundTag: 
           StringTag "name" value: 'minecraft:overworld'
           ByteTag "natural": 1
           Some more attributes ...

Known attributes :

Name Type Meaning Values
name String Dimension's name "minecraft:overworld", "minecraft:the_nether", "minecraft:the_end" or something else
natural Byte Is it a standard overworld like dimension 1: true, 0: false
ambient_light Float Ambient light 0.0 to 1.0
has_ceiling Byte Does the dimension have blocks on top ? Like the nether 1: true, 0: false
has_skylight Byte Does the dimension have natural sky light 1: true, 0: false
fixed_time Long Set fixed minecraft clock time 0 to 12000
shrunk Byte ? 1: true, 0: false
ultrawarm Byte ? 1: true, 0: false
has_raids Byte ? 1: true, 0: false
respawn_anchor_works Byte Wether or not respawn anchor can be used 1: true, 0: false
bed_works Byte Wether or not beds can be used 1: true, 0: false
piglin_safe Byte ? 1: true, 0: false
logical_height Byte / Int ? Maybe the world's max height in blocks ? ?
infiniburn String ? "" or minecraft resource "minecraft:..."

Respawn

To change the player's dimension (overworld/nether/end), send them a respawn packet with the appropriate dimension, followed by prechunks/chunks for the new dimension, and finally a position and look packet. You do not need to unload chunks, the client will do it automatically.

Packet ID State Bound To Field Name Field Type Notes
0x3B 0x3A Play Client Dimension Int Enum Identifier -1: The Nether, 0: The Overworld, 1: The End Valid dimensions are defined per dimension registry sent in Join Game
World Name Identifier Name of the world being spawned into
Hashed seed Long First 8 bytes of the SHA-256 hash of the world's seed.
Gamemode Unsigned Byte 0: survival, 1: creative, 2: adventure, 3: spectator. The hardcore flag is not included
Previous Gamemode Unsigned Byte 0: survival, 1: creative, 2: adventure, 3: spectator. The hardcore flag is not included. The previous gamemode. (More information needed)
Level Type String (16) Same as Join Game
Is Debug Boolean True if the world is a debug mode world; debug mode worlds cannot be modified and have predefined blocks
Is Flat Boolean True if the world is a superflat world; flat worlds have different void fog and a horizon at y=0 instead of y=63
Copy metadata Boolean If false, metadata is reset on the respawned player entity. Set to true for dimension changes (including the dimension change triggered by sending client status perform respawn to exit the end poem/credits), and false for normal respawns.
Huh.png The following information needs to be added to this page:
Does the new World Name field resolve this same-dimension issue?

Warning.png Avoid changing player's dimension to same dimension they were already in unless they are dead. If you change the dimension to one they are already in, weird bugs can occur, such as the player being unable to attack other players in new world (until they die and respawn).

If you must respawn a player in the same dimension without killing them, send two respawn packets, one to a different world and then another to the world you want. You do not need to complete the first respawn; it only matters that you send two packets.

Entity Properties

Sets attributes on the given entity.

Packet ID State Bound To Field Name Field Type Notes
0x59 0x58 Play Client Entity ID VarInt
Number Of Properties Int Number of elements in the following array
Property Key Array String (64) Identifier See below
Value Double See below
Number Of Modifiers VarInt Number of elements in the following array
Modifiers Array of Modifier Data See Attribute#Modifiers. Modifier Data defined below.

Known Key values (see also Attribute#Modifiers):

Key Default Min Max Label
generic.maxHealth generic.max_health 20.0 0.0 1024.0 Max Health
generic.followRange generic.follow_range 32.0 0.0 2048.0 Follow Range
generic.knockbackResistance generic.knockback_resistance 0.0 0.0 1.0 Knockback Resistance
generic.movementSpeed generic.movement_speed 0.7 0.0 1024.0 Movement Speed
generic.attackDamage generic.attack_damage 2.0 0.0 2048.0 Attack Damage
generic.attackSpeed generic.attack_speed 4.0 0.0 1024.0 Attack Speed
generic.flyingSpeed generic.flying_speed 0.4 0.0 1024.0 Flying Speed
generic.armor 0.0 0.0 30.0 Armor
generic.armorToughness generic.armor_toughness 0.0 0.0 20.0 Armor Toughness
generic.attackKnockback generic.attack_knockback 0.0 0.0 5.0 —
generic.luck 0.0 -1024.0 1024.0 Luck
horse.jumpStrength horse.jump_strength 0.7 0.0 2.0 Jump Strength
zombie.spawnReinforcements zombie.spawn_reinforcements 0.0 0.0 1.0 Spawn Reinforcements Chance
generic.reachDistance 5.0 0.0 1024.0 Player Reach Distance (Forge only)
forge.swimSpeed 1.0 0.0 1024.0 Swimming Speed (Forge only)

Unknown attributes will cause a game crash (MC-150405) due to the default minimum being larger than the default value.

Modifier Data structure:

Field Name Field Type Notes
UUID UUID
Amount Double May be positive or negative
Operation Byte See below

The operation controls how the base value of the modifier is changed.

  • 0: Add/subtract amount
  • 1: Add/subtract amount percent of the current value
  • 2: Multiply by amount percent

All of the 0's are applied first, and then the 1's, and then the 2's.

Declare Recipes

Packet ID State Bound To Field Name Field Type Notes
0x5B 0x5A Play Client Num Recipes VarInt Number of elements in the following array
Recipe Recipe ID Array Identifier
Type String The recipe type, see below
Data Optional, varies Additional data for the recipe. For some types, there will be no data.

Recipe types:

Type Description Data
crafting_shapeless Shapeless crafting recipe. All items in the ingredient list must be present, but in any order/slot. As follows:
Name Type Description
Group String Used to group similar recipes together in the recipe book. Tag is present in recipe JSON.
Ingredient count VarInt Number of elements in the following array
Ingredients Array of Ingredient
Result Slot
crafting_shaped Shaped crafting recipe. All items must be present in the same pattern (which may be flipped horizontally or translated) As follows:
Name Type Description
Width VarInt
Height VarInt
Group String Used to group similar recipes together in the recipe book. Tag is present in recipe JSON.
Ingredients Array of Ingredient Length is width * height. Indexed by x + (y * width).
Result Slot
crafting_special_armordye Recipe for dying leather armor None
crafting_special_bookcloning Recipe for copying contents of written books
crafting_special_mapcloning Recipe for copying maps
crafting_special_mapextending Recipe for adding paper to maps
crafting_special_firework_rocket Recipe for making firework rockets
crafting_special_firework_star Recipe for making firework stars
crafting_special_firework_star_fade Recipe for making firework stars fade between multiple colors
crafting_special_repairitem Recipe for repairing items via crafting
crafting_special_tippedarrow Recipe for crafting tipped arrows
crafting_special_bannerduplicate Recipe for copying banner patterns
crafting_special_banneraddpattern Recipe for adding patterns to banners
crafting_special_shielddecoration Recipe for applying a banner's pattern to a shield
crafting_special_shulkerboxcoloring Recipe for recoloring a shulker box
smelting Smelting recipe As follows:
Name Type Description
Group String Used to group similar recipes together in the recipe book.
Ingredient Ingredient
Result Slot
Experience Float
Cooking time VarInt
blasting Blast furnace recipe
smoking Smoker recipe
campfire_cooking Campfire recipe
stonecutting Stonecutter recipe As follows:
Name Type Description
Group String Used to group similar recipes together in the recipe book. Tag is present in recipe JSON.
Ingredient Ingredient
Result Slot
smithing Smithing table recipe As follows:
Name Type Description
Base Ingredient First item
Addition Ingredient Second item
Result Slot

Ingredient is defined as:

Name Type Description
Count VarInt Number of elements in the following array
Items Array of Slot Any item in this array may be used for the recipe. The count of each item should be 1.

Serverbound

Interact Entity

This packet is sent from the client to the server when the client attacks or right-clicks another entity (a player, minecart, etc).

A Notchian server only accepts this packet if the entity being attacked/used is visible without obstruction and within a 4-unit radius of the player's position.

Note that middle-click in creative mode is interpreted by the client and sent as a Creative Inventory Action packet instead.

Packet ID State Bound To Field Name Field Type Notes
0x0E Play Server Entity ID VarInt The ID of the entity to interact
Type VarInt Enum 0: interact, 1: attack, 2: interact at
Target X Optional Float Only if Type is interact at
Target Y Optional Float Only if Type is interact at
Target Z Optional Float Only if Type is interact at
Hand Optional VarInt Enum Only if Type is interact or interact at; 0: main hand, 1: off hand
Sneaking Boolean If the client is sneaking.

Generate Structure

Sent when Generate is pressed on the Jigsaw Block interface.

Packet ID State Bound To Field Name Field Type Notes
0x0F Play Server Location Position Block entity location
Levels VarInt Value of the levels slider/max depth to generate
Keep Jigsaws Boolean

Player Abilities (serverbound)

The latter 2 fields are used to indicate the walking and flying speeds respectively, while the first field is used to determine the value of 4 booleans.

The vanilla client sends this packet when the player starts/stops flying with the Flags parameter changed accordingly. All other parameters are ignored by the vanilla server.

Packet ID State Bound To Field Name Field Type Notes
0x19 0x1A Play Server Flags Byte Bit mask. 0x08: damage disabled (god mode), 0x04: can fly, 0x02: is flying, 0x01: is Creative
Flying Speed Float
Walking Speed Float

Update Jigsaw Block

Sent when Done is pressed on the Jigsaw Block interface.

Packet ID State Bound To Field Name Field Type Notes
0x27 0x28 Play Server Location Position Block entity location
Attachment type Identifier
Name Identifier
Target Identifier
Target pool Pool Identifier
Final state String "Turns into" on the GUI, final_state in NBT
Joint type String rollable if the attached piece can be rotated, else aligned

Entity Equipment

Packet ID State Bound To Field Name Field Type Notes
0x47 Play Client Entity ID VarInt Entity's EID
Slot VarInt Enum Equipment slot. 0: main hand, 1: off hand, 2–5: armor slot (2: boots, 3: leggings, 4: chestplate, 5: helmet)
Item Slot
Equipment Slot Array Byte Enum Equipment slot. 0: main hand, 1: off hand, 2–5: armor slot (2: boots, 3: leggings, 4: chestplate, 5: helmet). Also has the top bit set if another entry follows, and otherwise unset if this is the last item in the array.
Item Slot

Handshaking

Clientbound

There are no clientbound packets in the Handshaking state, since the protocol immediately switches to a different state after the client sends the first packet.

Serverbound

Handshake

This causes the server to switch into the target state.

Packet ID State Bound To Field Name Field Type Notes
0x00 Handshaking Server Protocol Version VarInt See protocol version numbers (currently 578 734)
Server Address String Hostname or IP, e.g. localhost or 127.0.0.1, that was used to connect. The Notchian server does not use this information. Note that SRV records are a complete redirect, e.g. if _minecraft._tcp.example.com points to mc.example.org, users connecting to example.com will provide mc.example.org as server address in addition to connecting to it.
Server Port Unsigned Short Default is 25565. The Notchian server does not use this information.
Next State VarInt Enum 1 for status, 2 for login

Status

Clientbound

No changes so far.

Serverbound

No changes so far.

Login

Clientbound

Login Success

Packet ID State Bound To Field Name Field Type Notes
0x02 Login Client UUID String (36) UUID Unlike in other packets, this field contains the UUID as a string with hyphens.
Username String (16)

This packet switches the connection state to play.

Serverbound

No changes so far.

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