minecraft_protocol/packets/catalog-play.md

Play-State Packet Catalog — Java Edition 1.21.1 (protocol 767)

Version lock: all IDs on this page are 1.21.1 (protocol 767). Play-state IDs shift between versions — sometimes heavily. See ../versions/1.21.md for the delta from 1.20.x, and ../versions/INDEX.md for the full version map.

Sources:

• minecraft-data: /tmp/mcproto-refs/minecraft-data/data/pc/1.21.1/protocol.json (packet IDs + field types, authoritative for 1.21.1)
• ViaVersion CB: /tmp/mcproto-refs/ViaVersion/common/src/main/java/com/viaversion/viaversion/protocols/v1_20_5to1_21/packet/ClientboundPackets1_21.java (ordered enum — ordinal = wire ID)
• ViaVersion SB: /tmp/mcproto-refs/ViaVersion/common/src/main/java/com/viaversion/viaversion/protocols/v1_20_3to1_20_5/packet/ServerboundPackets1_20_5.java (serverbound IDs unchanged from 1.20.5→1.21.1; no new SB enum file in the v1_20_5to1_21 package)

Totals (minecraft-data count): 124 clientbound, 58 serverbound = 182 play-state packets.

Notation:

• CB = Server→Client (clientbound)
• SB = Client→Server (serverbound)
• → format-*.md = that packet's binary layout has its own deep-dive doc in this directory
• <!-- UNCONFIRMED --> = claim not verified against a second source

---

1. Connection / System

Core session-maintenance and state-transition packets.

Clientbound

ID	ViaVersion name	mc-data name	Purpose
0x00	BUNDLE_DELIMITER	bundle_delimiter	Frame boundary: server wraps a group of CB packets between two 0x00 delimiters; client applies them atomically (added 1.19.4)
0x26	KEEP_ALIVE	keep_alive	Heartbeat: server sends random i64 ID; client must echo it within timeout or be kicked
0x35	PING	ping	Echoes an i32 ID back from client's PONG (not the status-ping; used for latency measurement mid-session)
0x36	PONG_RESPONSE	ping_response	Server response to client's PING_REQUEST (0x21 SB); carries i64 payload
0x1D	DISCONNECT	kick_disconnect	Kick with chat-component reason (Text component, NBT-encoded in 1.20.3+)
0x2B	LOGIN	login	Join Game — first play-state packet after configuration; see detail below
0x47	RESPAWN	respawn	Sent on dimension change or respawn; see detail below
0x53	SET_CARRIED_ITEM	held_item_slot	Sets the client's active hotbar slot (0–8)
0x69	START_CONFIGURATION	start_configuration	Transitions back to Configuration state for resource-pack / registry updates (1.20.2+)
0x19	CUSTOM_PAYLOAD	custom_payload	Plugin channel message (Identifier channel + byte blob)
0x16	COOKIE_REQUEST	cookie_request	Server requests a previously stored cookie value from the client (1.20.5+)
0x6B	STORE_COOKIE	store_cookie	Server pushes a key/value cookie to the client for later retrieval (1.20.5+)
0x73	TRANSFER	transfer	Transfers the client to a different server (host + port); 1.20.5+

Serverbound

ID	ViaVersion name	mc-data name	Purpose
0x18	KEEP_ALIVE	keep_alive	Echo of server's i64 keep-alive ID
0x27	PONG	pong	Echo of server's PING i32 ID
0x21	PING_REQUEST	ping_request	Client-initiated latency probe; carries i64 payload; server echoes via PONG_RESPONSE
0x00	ACCEPT_TELEPORTATION	teleport_confirm	Client acks a PLAYER_POSITION teleport by echoing its varint teleportId
0x0C	CONFIGURATION_ACKNOWLEDGED	configuration_acknowledged	Client acks START_CONFIGURATION, triggering transition back to Configuration state
0x11	COOKIE_RESPONSE	cookie_response	Response to COOKIE_REQUEST; carries key + optional value
0x12	CUSTOM_PAYLOAD	custom_payload	Plugin channel message (SB direction)
0x2B	RESOURCE_PACK	resource_pack_receive	Client reports resource-pack download status (accepted/declined/downloaded/failed)

---

Detail: LOGIN (0x2B CB) — Join Game

First play-state packet sent by the server (after Configuration → Play transition). Sets up the client's world context.

Fields (from protocol.json packet_login):

Field	Type	Notes
entityId	i32	Client's entity ID
isHardcore	bool
worldNames	varint-prefixed string[]	All dimension names known to the server
maxPlayers	varint	(informational, not enforced client-side)
viewDistance	varint	Server's configured view distance
simulationDistance	varint
reducedDebugInfo	bool	Hides debug overlay
enableRespawnScreen	bool
doLimitedCrafting	bool
worldState	SpawnInfo	Composite: dimension type ID, dimension name, hashed seed, gamemode, prev gamemode, debug/flat flags, death location (optional), portal cooldown
enforcesSecureChat	bool	If true, server requires signed chat messages

Detail: RESPAWN (0x47 CB)

Sent on dimension switch, death respawn, or /respawn. Resets world context without a full Login.

Fields (packet_respawn):

Field	Type	Notes
worldState	SpawnInfo	Same composite type as Login
copyMetadata	u8	Bitmask: bit 0 = keep attributes, bit 1 = keep entity data

---

2. Entity

Spawning, movement, metadata, equipment, effects, and removal.

Clientbound

ID	ViaVersion name	mc-data name	Purpose
0x01	ADD_ENTITY	spawn_entity	Spawn any non-XP entity; carries entity ID (varint), UUID, type (varint), position (f64×3), angles, data (varint, type-dependent), velocity
0x02	ADD_EXPERIENCE_ORB	spawn_entity_experience_orb	Spawn XP orb; entity ID + position + count (i16)
0x03	ANIMATE	animation	Play entity animation (swing arm, take damage, leave bed, etc.); entity ID + animation byte
0x2E	MOVE_ENTITY_POS	rel_entity_move	Delta position only (fixed-point i16×3); entity moved < 8 blocks
0x2F	MOVE_ENTITY_POS_ROT	entity_move_look	Delta position + rotation
0x30	MOVE_ENTITY_ROT	entity_look	Rotation only
0x48	ROTATE_HEAD	entity_head_rotation	Yaw of entity head (separate from body)
0x31	MOVE_VEHICLE	vehicle_move	Absolute position + rotation for mounted vehicle
0x70	TELEPORT_ENTITY	entity_teleport	Absolute position + rotation for entities beyond delta range (>8 blocks)
0x5A	SET_ENTITY_MOTION	entity_velocity	Velocity in fixed-point i16 units (1/8000 m/tick)
0x58	SET_ENTITY_DATA	entity_metadata	Entity metadata key-value stream; → format-entity-metadata.md
0x5B	SET_EQUIPMENT	entity_equipment	Equipment slots (main/off hand, 4 armor slots); slot bitmask + Slot data
0x76	UPDATE_MOB_EFFECT	entity_effect	Apply/update a potion effect (entity ID, effect ID, amplifier, duration, flags)
0x43	REMOVE_MOB_EFFECT	remove_entity_effect	Remove a specific effect from entity
0x59	SET_ENTITY_LINK	attach_entity	Attach entity A to entity B (leash); entity ID + vehicle ID (-1 to detach)
0x5F	SET_PASSENGERS	set_passengers	Set which entities are riding on a vehicle; vehicle entity ID + array of passenger IDs
0x42	REMOVE_ENTITIES	entity_destroy	Remove one or more entities by ID (varint array)
0x1F	ENTITY_EVENT	entity_status	Entity-specific status byte (e.g. death animation, tipped arrow hit, villager anger)
0x1A	DAMAGE_EVENT	damage_event	Entity took damage: entity ID, damage type, source entity/position (1.19.4+)
0x24	HURT_ANIMATION	hurt_animation	Visual-only hurt swing (entity ID + yaw); added 1.19.4
0x75	UPDATE_ATTRIBUTES	entity_update_attributes	Update base attribute values (movement speed, attack damage, etc.)
0x6F	TAKE_ITEM_ENTITY	collect	Entity picked up an item (item entity ID + collector entity ID + pickup count)
0x3F	PLAYER_LOOK_AT	face_player	Make entity/player face a position or another entity
0x79	PROJECTILE_POWER	set_projectile_power	Projectile acceleration: entity ID (VarInt) + accelerationPower (f64 scalar magnitude). In 1.20.5 the server sent three separate doubles (x/y/z); ViaVersion Protocol1_20_5To1_21.java converts the magnitude sqrt(x²+y²+z²) to the single scalar that 1.21+ uses. Source: minecraft-data/data/pc/1.21.1/protocol.json packet_set_projectile_power + ViaVersion/.../protocols/v1_20_5to1_21/Protocol1_20_5To1_21.java PROJECTILE_POWER handler.

Serverbound

ID	ViaVersion name	mc-data name	Purpose
0x1A	MOVE_PLAYER_POS	position	Player position update (f64 x/y/z + bool onGround)
0x1B	MOVE_PLAYER_POS_ROT	position_look	Position + yaw/pitch
0x1C	MOVE_PLAYER_ROT	look	Rotation only
0x1D	MOVE_PLAYER_STATUS_ONLY	flying	Ground status only (used when no other movement to report)
0x1E	MOVE_VEHICLE	vehicle_move	Absolute position + rotation while controlling a vehicle
0x16	INTERACT	use_entity	Interact with entity: entity ID + action (attack/interact/interact-at) + hand + position (for interact-at)
0x24	PLAYER_ACTION	block_dig	Block dig/place actions (start dig, cancel, finish, drop item, swap hands, shoot arrow) + location + face + sequence
0x25	PLAYER_COMMAND	entity_action	Player-state commands: sneak start/stop, sprint start/stop, leave bed, start/stop elytra, horse jump
0x36	SWING	arm_animation	Arm swing animation (main or off hand)
0x37	TELEPORT_TO_ENTITY	spectate	Spectator teleport to entity UUID
0x26	PLAYER_INPUT	steer_vehicle	Vehicle steering input (sideways/forward + flags for jump/unmount)
0x1F	PADDLE_BOAT	steer_boat	Boat paddle state (left + right bool)
0x20	PICK_ITEM	pick_item	Pick Block (middle-click); carries hotbar slot index
0x15	ENTITY_TAG_QUERY	query_entity_nbt	Debug: request entity NBT (debug build)

---

3. World

Chunks, blocks, lighting, world events, and world border.

Clientbound

ID	ViaVersion name	mc-data name	Purpose
0x27	LEVEL_CHUNK_WITH_LIGHT	map_chunk	Full chunk column + light data bundled; → format-chunk-data.md
0x2A	LIGHT_UPDATE	update_light	Update lighting only (no block data); same sky/block light structure as above; → format-chunk-data.md
0x0C	CHUNK_BATCH_FINISHED	chunk_batch_finished	Signals end of chunk batch; carries batch size (varint); client responds with CHUNK_BATCH_RECEIVED (1.20.2+)
0x0D	CHUNK_BATCH_START	chunk_batch_start	Signals start of chunk batch (1.20.2+)
0x0E	CHUNKS_BIOMES	chunk_biomes	Update biome data for existing chunks without re-sending block data (1.20+)
0x21	FORGET_LEVEL_CHUNK	unload_chunk	Unload a chunk column; i32 chunk X + Z
0x54	SET_CHUNK_CACHE_CENTER	update_view_position	Shift the client's chunk center (sent on player movement between chunks)
0x55	SET_CHUNK_CACHE_RADIUS	update_view_distance	Update render distance
0x09	BLOCK_UPDATE	block_change	Single block change: Position + block state ID (varint)
0x49	SECTION_BLOCKS_UPDATE	multi_block_change	Multiple block changes in one chunk section; section coords + array of `(localPos << 12
0x07	BLOCK_ENTITY_DATA	tile_entity_data	Update a block entity's NBT (chest, furnace, sign, etc.)
0x08	BLOCK_EVENT	block_action	Block action event (e.g. chest open/close sound, note block pitch, piston extension); location + action byte + action param + block type
0x06	BLOCK_DESTRUCTION	block_break_animation	Show block breaking animation progress (0–9) for a given entity ID at a position
0x05	BLOCK_CHANGED_ACK	acknowledge_player_digging	Server acknowledges a block-dig sequence number; carries sequence ID + position + block state + status + successful bool
0x28	LEVEL_EVENT	world_event	World event/sound (door open, explosion sound, portal, block break sound, etc.); event ID + position + data + global flag
0x20	EXPLODE	explosion	Explosion: position (f64), radius (f32), array of affected block offsets, player knockback velocity, interaction type, particles, sound
0x22	GAME_EVENT	game_state_change	Game state notifications: start/stop rain, change gamemode, win game, demo events, bed/respawn prompts, guardian elder effect, etc. Carries u8 reason + f32 value
0x56	SET_DEFAULT_SPAWN_POSITION	spawn_position	World spawn point (used for compass direction)
0x25	INITIALIZE_BORDER	initialize_world_border	Full world border state (center, size, lerp target, lerp time, warning blocks/time)
0x4D	SET_BORDER_CENTER	world_border_center	Update border center
0x4E	SET_BORDER_LERP_SIZE	world_border_lerp_size	Animate border size change
0x4F	SET_BORDER_SIZE	world_border_size	Set border size instantly
0x50	SET_BORDER_WARNING_DELAY	world_border_warning_delay	Warning time (seconds)
0x51	SET_BORDER_WARNING_DISTANCE	world_border_warning_reach	Warning distance (blocks)
0x64	SET_TIME	update_time	World age (i64, always incrementing) + time of day (i64, 0–24000; negative = frozen)
0x62	SET_SIMULATION_DISTANCE	simulation_distance	Server's entity simulation radius
0x71	TICKING_STATE	set_ticking_state	Tick rate + whether frozen (1.20.3+)
0x72	TICKING_STEP	step_tick	Advance frozen world by N ticks (1.20.3+)
0x0B	CHANGE_DIFFICULTY	difficulty	Current difficulty + locked flag

Serverbound

ID	ViaVersion name	mc-data name	Purpose
0x08	CHUNK_BATCH_RECEIVED	chunk_batch_received	Client reports desired chunks/tick back to server after batch (throttle feedback)
0x01	BLOCK_ENTITY_TAG_QUERY	query_block_nbt	Debug: request block entity NBT at position
0x02	CHANGE_DIFFICULTY	set_difficulty	Op changes world difficulty (op-only)
0x19	LOCK_DIFFICULTY	lock_difficulty	Op locks/unlocks difficulty
0x38	USE_ITEM_ON	block_place	Place/use block: hand + block position + face + cursor position + head-inside-block flag + sequence
0x39	USE_ITEM	use_item	Use item in hand (right-click in air): hand + sequence
0x17	JIGSAW_GENERATE	generate_structure	Generate jigsaw structure (op/debug)
0x30	SET_COMMAND_BLOCK	update_command_block	Update command block: position + command + mode + flags
0x31	SET_COMMAND_MINECART	update_command_block_minecart	Update command block in minecart
0x33	SET_JIGSAW_BLOCK	update_jigsaw_block	Update jigsaw block settings
0x34	SET_STRUCTURE_BLOCK	update_structure_block	Update structure block settings
0x35	SIGN_UPDATE	update_sign	Submit sign text (front/back): position + is-front-side + 4 lines

---

4. Inventory / Container

Opening, populating, and interacting with containers and the player inventory.

Clientbound

ID	ViaVersion name	mc-data name	Purpose
0x33	OPEN_SCREEN	open_window	Open a container UI; window ID + menu type (varint) + title (NBT text)
0x23	HORSE_SCREEN_OPEN	open_horse_window	Open horse inventory UI (separate from generic containers)
0x12	CONTAINER_CLOSE	close_window	Server closes a container (window ID)
0x13	CONTAINER_SET_CONTENT	window_items	Full slot sync for open container; window ID + stateId + Slot array + carried item; Slot type → format-slot-and-components.md
0x15	CONTAINER_SET_SLOT	set_slot	Update single slot; window ID + stateId + slot index (i16) + Slot; → format-slot-and-components.md
0x14	CONTAINER_SET_DATA	craft_progress_bar	Update a container "property" (furnace progress, enchant seed, etc.); window ID + property ID (i16) + value (i16)
0x32	OPEN_BOOK	open_book	Open a book UI (hand: main/off)
0x34	OPEN_SIGN_EDITOR	open_sign_entity	Open sign editor UI for a position; bool for front/back side
0x37	PLACE_GHOST_RECIPE	craft_recipe_response	Show recipe in crafting grid (response to PLACE_RECIPE SB)
0x17	COOLDOWN	set_cooldown	Start item use cooldown (item ID + ticks)
0x2D	MERCHANT_OFFERS	trade_list	Villager trade list (window ID + trades array + villager level/XP + regular villager + can restock)
0x2C	MAP_ITEM_DATA	map	Map item data (map ID + scale + locked + icons + patch data)

Serverbound

ID	ViaVersion name	mc-data name	Purpose
0x0F	CONTAINER_CLOSE	close_window	Client closed a container (window ID)
0x0E	CONTAINER_CLICK	window_click	Inventory click; window ID + stateId + slot (i16) + button + mode + changed slots array + cursor Slot
0x0D	CONTAINER_BUTTON_CLICK	enchant_item	Click a container button (enchanting table slot select, trade button, etc.)
0x10	CONTAINER_SLOT_STATE_CHANGED	set_slot_state	Toggle a slot state (crafting grid slot on/off — added 1.20.3, not 1.20.2). Source: ViaVersion/.../protocols/v1_20_2to1_20_3/packet/ServerboundPackets1_20_3.java (0x0F there; ID shifted to 0x10 in 1.20.5); absent from ServerboundPackets1_20_2. Protocol1_20_2To1_20_3.java cancels it toward older clients (cancelServerbound).
0x22	PLACE_RECIPE	craft_recipe_request	Request to auto-fill a recipe in crafting grid; window ID + recipe ID + make-all flag
0x32	SET_CREATIVE_MODE_SLOT	set_creative_slot	Creative-mode direct slot set; slot (i16) + Slot data
0x29	RECIPE_BOOK_SEEN_RECIPE	displayed_recipe	Mark a recipe as seen in the recipe book
0x28	RECIPE_BOOK_CHANGE_SETTINGS	recipe_book	Toggle recipe book filter/open state
0x2A	RENAME_ITEM	name_item	Submit anvil rename string
0x2E	SET_BEACON	set_beacon_effect	Set beacon effect (primary + secondary effect IDs)
0x2D	SELECT_TRADE	select_trade	Select villager trade by index
0x14	EDIT_BOOK	edit_book	Submit book contents (hand + pages array + optional title)

---

5. Player

Position synchronization, health, XP, abilities, and player list.

Clientbound

ID	ViaVersion name	mc-data name	Purpose
0x40	PLAYER_POSITION	position	Synchronize player position: server-authoritative teleport; fields: x/y/z (f64), yaw/pitch (f32), flags (PositionUpdateRelatives bitmask — absolute vs relative per axis), teleportId (varint); client must confirm with ACCEPT_TELEPORTATION; see field detail below
0x38	PLAYER_ABILITIES	abilities	Player ability flags (invulnerable, flying, allow-fly, creative-mode) + fly speed + field-of-view modifier
0x5D	SET_HEALTH	update_health	Health (f32), food (varint), saturation (f32)
0x5C	SET_EXPERIENCE	experience	XP bar progress (f32 0–1) + total XP levels (varint) + total XP points (varint)
0x3E	PLAYER_INFO_UPDATE	player_info	Add/update player list entries; bitmask of actions (add player, initialize chat, update gamemode, update listed, update latency, update display name) + array of UUID + per-action data
0x3D	PLAYER_INFO_REMOVE	player_remove	Remove player list entries by UUID array
0x3A	PLAYER_COMBAT_END	end_combat_event	Player exited combat (duration + entity ID)
0x3B	PLAYER_COMBAT_ENTER	enter_combat_event	Player entered combat
0x3C	PLAYER_COMBAT_KILL	death_combat_event	Player killed in combat (player entity ID + death message)
0x39	PLAYER_CHAT	player_chat	Signed player chat message; see field detail below
0x09	CLIENT_COMMAND (mismap)	—	See SB below
0x52	SET_CAMERA	camera	Set which entity the player's camera follows
0x31	MOVE_VEHICLE	vehicle_move	Sync vehicle position to client

Serverbound

ID	ViaVersion name	mc-data name	Purpose
0x09	CLIENT_COMMAND	client_command	Perform client action: 0 = respawn, 1 = open inventory stats
0x0A	CLIENT_INFORMATION	settings	Client settings: locale, view distance, chat mode, colors, skin parts, main hand, filter text, allow server listings
0x23	PLAYER_ABILITIES	abilities	Client reports flying flag (bit 1); other flags ignored by server
0x2F	SET_CARRIED_ITEM	held_item_slot	Change held hotbar slot (0–8)
0x0B	COMMAND_SUGGESTION	tab_complete	Tab-complete request; transactionId (varint) + partial command string
0x13	DEBUG_SAMPLE_SUBSCRIPTION	debug_sample_subscription	Subscribe to debug performance samples (tick duration, ping, etc.)

---

Detail: PLAYER_POSITION (0x40 CB) — Synchronize Player Position

The server asserts the player's canonical position. Client must respond with ACCEPT_TELEPORTATION (0x00 SB) carrying the same teleportId before sending movement packets will be trusted again.

Fields (from protocol.json packet_position):

Field	Type	Notes
x	f64
y	f64
z	f64
yaw	f32
pitch	f32
flags	PositionUpdateRelatives (u8 bitmask)	Bit 0=X, 1=Y, 2=Z, 3=pitch, 4=yaw: if set, the value is relative to current
teleportId	varint	Client echoes in ACCEPT_TELEPORTATION

---

6. UI / HUD

Chat messages (all three kinds), titles, scoreboard, boss bar, tab list.

Clientbound

ID	ViaVersion name	mc-data name	Purpose
0x6C	SYSTEM_CHAT	system_chat	System message (NBT text component + isActionBar bool); used for /say, /tell, server announcements
0x39	PLAYER_CHAT	player_chat	Signed player chat; carries sender UUID, message, timestamp, signature (256-byte optional), chat type decoration reference, optional unsigned fallback; see detail below
0x1E	DISGUISED_CHAT	profileless_chat	System-style chat that mimics a player message without a UUID (no signature); added 1.19.3
0x1C	DELETE_CHAT	hide_message	Delete a previously sent signed chat message by signature hash
0x65	SET_TITLE_TEXT	set_title_text	Show title (NBT text)
0x63	SET_SUBTITLE_TEXT	set_title_subtitle	Show subtitle (NBT text)
0x4C	SET_ACTION_BAR_TEXT	action_bar	Action bar message (NBT text)
0x66	SET_TITLES_ANIMATION	set_title_time	Title timing: fade-in, stay, fade-out (all i32 ticks)
0x0F	CLEAR_TITLES	clear_titles	Clear title/subtitle/action bar; bool reset (resets timing)
0x0A	BOSS_EVENT	boss_bar	Boss bar operation: ADD, REMOVE, UPDATE_HEALTH, UPDATE_TITLE, UPDATE_STYLE, UPDATE_FLAGS; UUID + per-action data
0x6D	TAB_LIST	playerlist_header	Tab list header + footer (both NBT text)
0x5E	SET_OBJECTIVE	scoreboard_objective	Create/remove/update scoreboard objective; name + mode (0=create,1=remove,2=update) + display name + type
0x61	SET_SCORE	scoreboard_score	Set an entity's score for an objective; entity name + objective name + score (varint) + optional display name + optional number format
0x44	RESET_SCORE	reset_score	Remove a score entry; entity name + optional objective name (1.20.3+)
0x57	SET_DISPLAY_OBJECTIVE	scoreboard_display_objective	Set which objective appears in a display slot (sidebar, list, below-name)
0x60	SET_PLAYER_TEAM	teams	Scoreboard team operations: CREATE, REMOVE, INFO_UPDATE, ADD_PLAYERS, REMOVE_PLAYERS
0x18	CUSTOM_CHAT_COMPLETIONS	chat_suggestions	Add/remove/set chat autocomplete suggestions (1.19.1+)
0x0B	CHANGE_DIFFICULTY (mismap)	difficulty	See World § above
0x1B	DEBUG_SAMPLE	debug_sample	Performance debug sample push (tick durations, etc.)

Serverbound

ID	ViaVersion name	mc-data name	Purpose
0x06	CHAT	chat_message	Player chat message; text + timestamp + salt + optional signature + ack bitset
0x04	CHAT_COMMAND	chat_command	Run command (unsigned); command string
0x05	CHAT_COMMAND_SIGNED	chat_command_signed	Run command with signed arguments (1.19.1+)
0x07	CHAT_SESSION_UPDATE	chat_session_update	Update session signing key (public key + expiry + signature)
0x03	CHAT_ACK	message_acknowledgement	Acknowledge received signed chat messages (cumulative offset into message history)

---

Detail: PLAYER_CHAT (0x39 CB) — Signed Chat

Fields (protocol.json packet_player_chat):

Field	Type	Notes
senderUuid	UUID
index	varint	Position in sender's message sequence
signature	optional byte[256]	RSA-signed message hash; absent for unsigned messages
plainMessage	string	Raw text
timestamp	i64	Unix ms
salt	i64
previousMessages	previousMessages	Compact acknowledgment of prior messages (used for signature chaining)
unsignedChatContent	optional NBT	Decorated/filtered version if different from plain
filterType	varint	0=pass-through, 1=fully-filtered, 2=partially-filtered
filterTypeMask	conditional	Bitmask when filterType=2
type	ChatTypesHolder	Reference into registry for formatting (chat, say-command, etc.)
networkName	NBT	Sender's display name
networkTargetName	optional NBT	Target for directed messages (whisper, /tell)

---

7. Commands / Recipes

The command graph, tab-complete, and recipe synchronization.

Clientbound

ID	ViaVersion name	mc-data name	Purpose
0x11	COMMANDS	declare_commands	Full command graph as a node tree; → format-command-graph.md
0x10	COMMAND_SUGGESTIONS	tab_complete	Tab-complete response; transactionId + match start + length + array of (text, optional tooltip)
0x77	UPDATE_RECIPES	declare_recipes	Full recipe list (crafting, smelting, stonecutting, etc.)
0x41	RECIPE	unlock_recipes	Recipe book state: action (init/add/remove) + recipe IDs shown + recipe IDs highlighted + display settings
0x37	PLACE_GHOST_RECIPE	craft_recipe_response	(Repeat from Inventory §) Display recipe in crafting grid
0x4A	SELECT_ADVANCEMENTS_TAB	select_advancement_tab	Open advancement tab (optional identifier)
0x74	UPDATE_ADVANCEMENTS	advancements	Advancement data: reset flag + added map + removed IDs + progress map

Serverbound

ID	ViaVersion name	mc-data name	Purpose
0x0B	COMMAND_SUGGESTION	tab_complete	Tab-complete request (see Player §5 SB)
0x22	PLACE_RECIPE	craft_recipe_request	(Repeat from Inventory §)
0x28	RECIPE_BOOK_CHANGE_SETTINGS	recipe_book	Recipe book toggle
0x29	RECIPE_BOOK_SEEN_RECIPE	displayed_recipe	Mark recipe seen
0x2C	SEEN_ADVANCEMENTS	advancement_tab	Open/close an advancement tab

---

8. Sound / Particle

Clientbound

ID	ViaVersion name	mc-data name	Purpose
0x68	SOUND	sound_effect	Named sound at fixed position (sound ID varint, category, x/y/z as fixed-point i32, volume f32, pitch f32, seed i64)
0x67	SOUND_ENTITY	entity_sound_effect	Same but position follows an entity ID
0x6A	STOP_SOUND	stop_sound	Stop sounds matching a category (optional) and/or sound ID (optional)
0x29	LEVEL_PARTICLES	world_particles	Spawn particle effect: particle type + data + position (f64) + offset (f32×3) + max speed + count + long-range flag
0x28	LEVEL_EVENT	world_event	(See World §) Also carries many sound/effect IDs

Serverbound

(No SB packets for sound/particle — client never requests specific sounds.)

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9. Misc

Tags, resource packs, server info, and debug/telemetry.

Clientbound

ID	ViaVersion name	mc-data name	Purpose
0x78	UPDATE_TAGS	tags	Registry tag lists (block, item, fluid, entity type, etc.); map of registry → array of (tag ID + value IDs)
0x46	RESOURCE_PACK_PUSH	add_resource_pack	Push a resource pack to client: UUID + URL + hash + forced + optional prompt message (1.20.3: UUID-keyed; 1.20.5: stacks)
0x45	RESOURCE_PACK_POP	remove_resource_pack	Remove a previously pushed resource pack by UUID (optional; clear all if absent)
0x4B	SERVER_DATA	server_data	Server icon (optional PNG bytes) + enforces-secure-chat flag (sent once at login)
0x6E	TAG_QUERY	nbt_query_response	Response to block/entity NBT query; transaction ID + NBT
0x04	AWARD_STATS	statistics	Statistics update (category + statistic + value; varint array)
0x2C	MAP_ITEM_DATA	map	(See Inventory §)
0x3C	PLAYER_COMBAT_KILL	death_combat_event	(See Player §)
0x7A	CUSTOM_REPORT_DETAILS	custom_report_details	Key-value map sent to crash reports (1.21+)
0x7B	SERVER_LINKS	server_links	List of labeled URLs (bug report, feedback, support, etc.) shown in pause menu (1.21+)

Serverbound

ID	ViaVersion name	mc-data name	Purpose
0x2B	RESOURCE_PACK	resource_pack_receive	Client status for a resource pack UUID: accepted/declined/success/failed

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Cross-links

• Slot type (used in container packets): format-slot-and-components.md — Slot encoding, item component NBT, 1.20.5 data-driven component format
• Entity metadata: format-entity-metadata.md — per-type metadata keys, value encoding
• Chunk data + lighting: format-chunk-data.md — section encoding, palette, heightmaps, block entity list, sky/block light arrays
• Command graph: format-command-graph.md — node types, flags, parser IDs, redirect mechanism
• Version deltas: ../versions/1.21.md — what changed 1.20.5→1.21; ../versions/INDEX.md — full version map

Note

: The format-*.md cross-link targets do not exist yet in this directory — they are planned deep-dive docs. Links will resolve when those docs are written.

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Version caveat

Play-state packet IDs change frequently between versions. Examples of large shifts:

Version range	Notable shift
1.19 → 1.19.1	Chat signing added; PLAYER_CHAT restructured
1.20.2	Configuration state added; START_CONFIGURATION 0x69 is new
1.20.3	NBT chat components replace string; SET_SCORE/RESET_SCORE split
1.20.5	Item components (data-driven Slot); cookies; resource-pack UUID stacking; PROJECTILE_POWER (0x79) added
1.21 (767)	SERVER_LINKS (0x7B) and CUSTOM_REPORT_DETAILS (0x7A) added in play state; same packets added in Configuration state

Always cross-check IDs against minecraft-data/data/pc/<version>/protocol.json or the ViaVersion ClientboundPackets<version> enum for the target version.