UE Audio MCP Plugin — TCP Control (42 Commands)
Drive the C++ TCP server inside Unreal Editor. All commands use 4-byte big-endian length prefix + UTF-8 JSON on 127.0.0.1:9877.
Requires the UE Audio MCP Plugin installed in your UE5 project.
Connection
# Python SDK
from ue_audio_mcp.ue5_connection import get_ue5_connection
conn = get_ue5_connection()
resp = conn.send_command({"action": "ping"})
# Raw TCP
python3 -c "
import socket, struct, json
s = socket.socket(); s.settimeout(5); s.connect(('127.0.0.1', 9877))
p = json.dumps({'action':'ping'}).encode()
s.sendall(struct.pack('>I', len(p)) + p)
r = s.recv(4); l = struct.unpack('>I', r)[0]; print(json.loads(s.recv(l)))
"
All 42 Commands
System (1)
| Command | Params | Returns |
|---|
ping | — | engine, version, project, features[] |
MetaSounds Builder Lifecycle (3)
| Command | Params | Returns |
|---|
create_builder | asset_type (Source/Patch/Preset), name | asset_type, name |
add_interface | interface | — |
build_to_asset | name, path (/Game/...) | name, path |
Graph I/O (2)
| Command | Params | Returns |
|---|
add_graph_input | name, type, default? | name, type |
add_graph_output | name, type | name, type |
Node Operations (3)
| Command | Params | Returns |
|---|
add_node | id, node_type, position? [x,y] | id, node_type |
set_default | node_id, input, value | node_id, input |
connect | from_node, from_pin, to_node, to_pin | all four |
__graph__ = sentinel node ID for graph boundary connections.
Audition & Editor (3)
| Command | Params | Returns |
|---|
audition | name? | — |
stop_audition | — | — |
open_in_editor | — | — |
Graph Variables (3, UE 5.7+)
| Command | Params | Returns |
|---|
add_graph_variable | name, type, default? | name, type |
add_variable_get_node | id, variable_name, delayed? | id, variable_name |
add_variable_set_node | id, variable_name | id, variable_name |
Presets (2)
| Command | Params | Returns |
|---|
convert_to_preset | referenced_asset (/Game/...) | referenced_asset |
convert_from_preset | — | — |
Query & Export (7)
| Command | Params | Returns |
|---|
list_node_classes | filter?, limit? (200), include_pins?, include_metadata? | nodes[], total, shown |
list_metasound_nodes | *(alias for list_node_classes)* | same |
get_node_locations | asset_path | nodes[], edges[] |
get_graph_input_names | — | names[], count |
set_live_updates | enabled (bool) | enabled |
export_metasound | asset_path | asset_type, is_preset, interfaces[], graph_inputs[], graph_outputs[], variables[], nodes[], edges[] |
list_blueprint_functions | filter?, class_filter?, audio_only?, limit?, include_pins?, list_classes_only? | functions[], total |
Blueprint & Assets (4)
| Command | Params | Returns |
|---|
call_function | function, args? | function, return_value? |
list_assets | class_filter?, path?, limit? | assets[], total, shown |
scan_blueprint | asset_path, audio_only?, include_pins? | graphs[], audio_summary |
export_audio_blueprint | asset_path | nodes[], edges[], audio_summary |
Allowlisted functions: PlaySound2D, PlaySoundAtLocation, SpawnSoundAtLocation, SpawnSound2D, SetSoundMixClassOverride, ClearSoundMixClassOverride, PushSoundMixModifier, PopSoundMixModifier, SetGlobalPitchModulation, SetGlobalListenerFocusParameters, PlayDialogue2D, PlayDialogueAtLocation, SpawnDialogue2D, SpawnDialogueAtLocation, GetPlayerCameraManager, GetPlayerController, GetPlayerPawn.
class_filter values: Blueprint, WidgetBlueprint, AnimBlueprint, MetaSoundSource, MetaSoundPatch, SoundWave, SoundCue, SoundAttenuation, SoundClass, SoundConcurrency, SoundMix, ReverbEffect.
Blueprint Builder (7)
| Command | Params | Returns |
|---|
bp_open_blueprint | asset_path | asset_path, graphs[] |
bp_add_node | kind (CallFunction/CustomEvent/VariableGet/VariableSet), name, graph? | node_id, kind, name |
bp_connect_pins | from_node, from_pin, to_node, to_pin | all four |
bp_set_pin_default | node_id, pin_name, value | node_id, pin_name |
bp_compile | — | success, errors[], warnings[] |
bp_register_existing_node | node_id, graph? | node_id, name, kind |
bp_list_pins | node_id | pins[] (name, type, direction, connected, default) |
Node kinds: CallFunction (audio API calls), CustomEvent (event receivers), VariableGet/VariableSet (Blueprint variables). Security: Only allowlisted audio functions can be called — prevents arbitrary code execution.
World Audio Setup (7)
| Command | Params | Returns |
|---|
place_anim_notify | animation_path, notify_type, time, sound? | animation_path, notify_type, time |
place_bp_anim_notify | animation_path, notify_class, time | animation_path, time |
spawn_audio_emitter | sound_path, location [x,y,z], name?, attenuation? | name, location |
import_sound_file | file_path, destination | source_path, destination, asset_name |
set_physical_surface | material_path, surface_type | material_path, surface_type |
place_audio_volume | location [x,y,z], extent [x,y,z], name?, reverb_effect?, priority? | name, location, volume_extent |
spawn_blueprint_actor | blueprint_path, location [x,y,z], name?, rotation? [p,y,r] | name, blueprint_path, location |
Assets (1)
| Command | Params | Returns |
|---|
duplicate_asset | source_path, dest_path, dest_name | source_path, dest_path |
Key Pin Names
- Sine/Saw/Square/Triangle: IN: Frequency, Phase Offset, Glide, Bias; OUT: Audio
- AD Envelope: IN: Trigger, Attack Time, Decay Time; OUT: Out Envelope
- ADSR Envelope: IN: Trigger Attack, Trigger Release, Attack Time, Decay Time, Sustain Level, Release Time; OUT: Out Envelope
- Biquad Filter: IN: In, Cutoff Frequency, Bandwidth, Filter Type; OUT: Out
- Wave Player: IN: Play, Stop, Wave Asset, Start Time, Loop, Pitch Shift; OUT: Out Audio, On Finished
- Multiply/Add (Audio): IN: Primary Operand, Operand; OUT: Out
- Map Range: IN: Value, In Range A, In Range B, Out Range A, Out Range B, Clamped; OUT: Out
Full pin reference: scripts/ms_node_specs.json (93 nodes, 464 pins)
Example Workflows
Simple Sine → Output
{"action":"create_builder", "asset_type":"Source", "name":"MySine"}
{"action":"add_interface", "interface":"MetaSound"}
{"action":"add_graph_output", "name":"Out Mono", "type":"Audio"}
{"action":"add_node", "id":"osc", "node_type":"UE::Sine::Audio"}
{"action":"set_default", "node_id":"osc", "input":"Frequency", "value":440}
{"action":"connect", "from_node":"osc", "from_pin":"Audio", "to_node":"__graph__", "to_pin":"Out Mono"}
{"action":"build_to_asset", "name":"MySine", "path":"/Game/Audio/MCP"}
Blueprint Audio Wiring
{"action":"bp_open_blueprint", "asset_path":"/Game/BP_Player"}
{"action":"bp_add_node", "kind":"CallFunction", "name":"PlaySound2D"}
{"action":"bp_add_node", "kind":"CustomEvent", "name":"OnFootstep"}
{"action":"bp_connect_pins", "from_node":"OnFootstep", "from_pin":"then", "to_node":"PlaySound2D", "to_pin":"execute"}
{"action":"bp_compile"}
World Audio Setup
{"action":"import_sound_file", "file_path":"/sounds/footstep_concrete_01.wav", "destination":"/Game/Audio/Footsteps"}
{"action":"spawn_audio_emitter", "sound_path":"/Game/Audio/Ambient/Wind", "location":[0,0,100], "name":"WindEmitter"}
{"action":"place_audio_volume", "location":[0,0,200], "extent":[500,500,300], "reverb_effect":"/Game/Audio/Reverb/LargeHall"}
{"action":"place_anim_notify", "animation_path":"/Game/Anims/Walk", "notify_type":"PlaySound", "time":0.3, "sound":"/Game/Audio/Footsteps/Step01"}
Project Scan & Export
{"action":"list_assets", "class_filter":"Blueprint"}
{"action":"scan_blueprint", "asset_path":"/Game/BP_Player", "audio_only":true}
{"action":"list_assets", "class_filter":"MetaSoundSource"}
{"action":"export_metasound", "asset_path":"/Game/Audio/MS_Gunshot"}
Or batch: python scripts/scan_project.py --full-export --import-db --rebuild-embeddings
Gotchas
- Must call
create_builder before any node/connection ops __graph__ is NOT a real node — it's the boundary sentinel- Path must start with
/Game/ or /Engine/, no .. - Audio vs Float: cannot cross-connect — use correct node variant
- TCP drops after ~17 rapid commands — use reconnect with progressive delay
- Builder state is global — only one active builder at a time
list_node_classes discovers real class names — the 65-name registry may miss some- BP Builder is additive-only — no node deletion (add nodes + wire, don't remove)
bp_compile may fail silently — check errors[] in response- World commands spawn into the current editor level — save before spawning
Source Files
- C++ plugin: UE-AUDIO-MCP (42 commands, TCP:9877)
- Python tools:
src/ue_audio_mcp/tools/ - Node registry:
src/ue_audio_mcp/knowledge/metasound_nodes.py (195 nodes, 1053 entries)
$ARGUMENTS
