UE5 Ultimate MCP

An open-source plugin that lets AI coding assistants control the Unreal Engine 5 editor — Blueprints, Materials, Sequencer, AI, World Building, and more.

Status: Alpha / Untested — built by combining three great open-source projects and adding new tool categories. Needs real-world testing.

What it does

You open your UE5 project, start Claude Code (or any MCP-compatible AI), and tell it what to build:

> "Add a health variable to the player blueprint, wire up a damage event, and create a HUD widget showing the health bar"

The AI uses 158 tools to directly manipulate the editor — creating Blueprints, wiring nodes, spawning actors, editing materials, setting up animations — without you clicking through menus.

Quick Start

You need: UE 5.7, Node.js 18+, Claude Code

Option 1 — Claude Code Plugin (easiest)

Install as a Claude Code plugin — no manual copying or build steps:

/plugin marketplace add https://github.com/NodeNestor/nestor-plugins
/plugin install ue5-ultimate-mcp

Then in your UE5 project folder, just say:

/setup-ue5

Claude will automatically copy the plugin into your project, detect if it's a C++ or Blueprint-only project, and set everything up.

Option 2 — Manual setup

1. Get the plugin into your UE5 project

Pre-built binary (Blueprint-only projects): Download from Releases and extract into YourGame/Plugins/UE5UltimateMCP/.

From source (C++ projects):

git clone https://github.com/NodeNestor/UE5UltimateMCP.git
cp -r UE5UltimateMCP YourGame/Plugins/UE5UltimateMCP

2. Register the MCP server

claude mcp add ue5 -- node Plugins/UE5UltimateMCP/MCP/dist/index.js

3. Use it

1. Open your project in UE5 — the plugin starts automatically (HTTP server on port 9847)
2. Open a terminal in the same project folder
3. Run claude
4. Ask it to do things

First time? Try: "Check the server status and tell me how many tools are available"

What's inside

This project stands on the shoulders of three excellent open-source UE5 MCP integrations:

Source Project	What we took	Credit
BlueprintMCP by mirno-ehf	Blueprint read/write, Materials, Animation, Snapshots — the surgical graph editing tools (83 tools)	Core of our Blueprint and Material systems
UnrealClaude by Natfii	Tool registry pattern, viewport capture, smart tool routing, context injection	Architecture inspiration + viewport/editor tools
unreal-engine-mcp by flopperam	Actor management, procedural world generation (castles, towns, mazes)	World gen algorithms + actor tools

We combined the best parts into a single plugin and added 46 new tools for categories none of them covered:

• Sequencer — keyframes, camera cuts, render to video
• Behavior Trees — tasks, decorators, blackboard, composites
• Navigation — nav mesh building, pathfinding, modifiers
• Data Tables — create, add rows, import CSV
• Foliage — scatter instances, foliage types
• Niagara — particle systems, emitters, parameters
• UI / UMG — widget blueprints, child widgets, event binding
• Build & Package — lighting, cook, package, commandlets

Note: CLAUDIUS ($60 on FAB) covers similar ground with 130+ commands and is a tested, production product. This is the free open-source alternative — less polished, but MIT licensed and extensible.

All 158 Tools

Actors (8) — Spawn, delete, transform, inspect actors

Tool	Description
spawn_actor	Spawn by class (StaticMesh, PointLight, Camera, etc.)
delete_actor	Remove an actor from the level
get_actors_in_level	List all actors with transforms
find_actors_by_name	Search by name pattern
set_actor_transform	Set location, rotation, scale
spawn_blueprint_actor	Spawn a Blueprint instance
get_actor_properties	Read all editable properties
set_actor_property	Set a property by name

Blueprint Read (8) — Inspect Blueprints without modifying

Tool	Description
list_blueprints	List all Blueprint assets
get_blueprint	Get graphs, variables, functions
get_blueprint_graph	Full node graph with pins
search_blueprints	Search by name, class, content
get_blueprint_summary	Concise structure overview
describe_graph	Human-readable logic description
find_asset_references	Find what references a Blueprint
search_by_type	Search assets by UClass

Blueprint Mutation (13) — Edit Blueprint graphs

Tool	Description
add_node	Add function, event, flow control nodes
delete_node	Remove a node
move_node	Reposition in graph
connect_pins	Wire two pins together
disconnect_pin	Break a connection
set_pin_default	Set default pin value
duplicate_nodes	Copy nodes
set_node_comment	Add/edit comment
refresh_all_nodes	Fix stale references
replace_function_calls	Bulk-replace function calls
rename_asset	Rename with redirectors
delete_asset	Delete an asset
set_blueprint_default	Set CDO default value

Blueprint Graphs (5) — Create and manage graphs

Tool	Description
create_blueprint	Create new Blueprint (Actor, Pawn, Interface, etc.)
create_graph	Create function or macro graph
delete_graph	Remove a graph
rename_graph	Rename a graph
reparent_blueprint	Change parent class

Variables (4)

add_variable, remove_variable, change_variable_type, set_variable_metadata

Parameters (3)

add_function_parameter, remove_function_parameter, change_function_parameter_type

Components (3)

list_components, add_component, remove_component

Interfaces (3)

list_interfaces, add_interface, remove_interface

Event Dispatchers (2)

add_event_dispatcher, list_event_dispatchers

User Types (4)

create_struct, create_enum, add_struct_property, remove_struct_property

Discovery (5)

list_classes, list_functions, list_properties, get_pin_info, check_pin_compatibility

Snapshots & Diff (6)

snapshot_graph, diff_graph, restore_graph, find_disconnected_pins, analyze_rebuild_impact, diff_blueprints

Validation (2)

validate_blueprint, validate_all_blueprints

Material Read (8)

list_materials, get_material, get_material_graph, describe_material, search_materials, find_material_references, list_material_functions, get_material_function

Material Mutation (14)

create_material, set_material_property, add_material_expression, delete_material_expression, connect_material_pins, disconnect_material_pin, set_expression_value, move_material_expression, create_material_instance, set_material_instance_parameter, snapshot_material_graph, diff_material_graph, restore_material_graph, validate_material

Animation (10)

create_anim_blueprint, add_anim_state, remove_anim_state, add_anim_transition, set_transition_rule, add_anim_node, add_state_machine, set_state_animation, create_blend_space, set_blend_space_samples

Sequencer (7) — NEW

create_level_sequence, add_actor_to_sequence, add_transform_keyframe, add_camera_cut, set_sequence_length, render_sequence_to_video, play_sequence

Behavior Trees (9) — NEW

create_behavior_tree, create_blackboard, add_blackboard_key, add_bt_task, add_bt_decorator, add_bt_service, add_bt_selector, add_bt_sequence, link_blackboard_to_tree

Navigation (5) — NEW

build_navigation, add_nav_mesh_bounds, test_path, get_nav_mesh_info, add_nav_modifier

Data Tables (5) — NEW

create_data_table, add_data_table_row, get_data_table_rows, remove_data_table_row, import_csv_to_data_table

Foliage (4) — NEW

scatter_foliage, add_foliage_type, clear_foliage, get_foliage_info

Niagara (5) — NEW

create_niagara_system, spawn_niagara_actor, add_niagara_emitter, set_niagara_parameter, list_niagara_systems

UI / UMG (5) — NEW

create_widget_blueprint, add_widget_child, set_widget_property, list_widget_blueprints, bind_widget_event

World Generation (9)

create_wall, create_tower, create_staircase, create_arch, create_pyramid, create_maze, create_castle, create_town, create_house

Build & Package (6) — NEW

build_lighting, build_navigation_only, cook_project, package_project, get_build_status, run_commandlet

Viewport & Editor (5)

capture_viewport, get_output_log, run_console_command, open_level, get_level_info

How it works

Claude Code  ←stdio→  TypeScript Bridge  ←HTTP :9847→  C++ Plugin in UE5 Editor
                       (translates MCP          (runs tools on the
                        protocol to HTTP)         game thread)

1. The C++ plugin loads when you open UE5 and starts an HTTP server on port 9847
2. The TypeScript bridge connects Claude Code to that server
3. When Claude calls a tool, the bridge POSTs to the plugin, which executes on the game thread
4. New C++ tools auto-appear in Claude — no TypeScript changes needed

Testing

Once UE5 is running with the plugin:

# Check if the server is responding
python tests/test_health.py

# Run integration tests (spawns actors, captures viewport, etc.)
python tests/test_tools.py

# Test world generation (creates and cleans up structures)
python tests/test_worldgen.py

Adding new tools

Create a handler in Source/.../Private/Handlers/:

#include "Tools/MCPToolBase.h"
#include "Tools/MCPToolRegistry.h"

class FTool_MyThing : public FMCPToolBase
{
public:
    FMCPToolInfo GetInfo() const override
    {
        FMCPToolInfo Info;
        Info.Name = TEXT("my_thing");
        Info.Description = TEXT("Does a thing");
        Info.Annotations.Category = TEXT("MyCategory");
        return Info;
    }

    FMCPToolResult Execute(const TSharedPtr<FJsonObject>& Params) override
    {
        // UE5 API calls here...
        TSharedPtr<FJsonObject> Result = MakeShared<FJsonObject>();
        Result->SetStringField(TEXT("status"), TEXT("done"));
        return FMCPToolResult::Ok(Result);
    }
};

namespace UltimateMCPTools {
    void RegisterMyTools() {
        FMCPToolRegistry::Get().Register(MakeShared<FTool_MyThing>());
    }
}

Register it in UltimateMCPSubsystem.cpp and it auto-appears in Claude.

Requirements

• Unreal Engine 5.7 (pre-built binary is compiled against 5.7 — source may work on 5.4+ with minor API tweaks)
• Node.js 18+
• Claude Code (or any MCP-compatible AI client)

License

MIT — do whatever you want with it.

Acknowledgments

This project wouldn't exist without:

• mirno-ehf/ue5-mcp — The Blueprint and Material editing tools are adapted from this project. Their HTTP server architecture, queued game-thread execution, and SEH crash safety patterns form the backbone of our plugin.
• Natfii/UnrealClaude — The tool registry pattern, smart tool routing (mega-tool collapsing), and context injection system are inspired by this project. Their MCP bridge architecture influenced our TypeScript wrapper.
• flopperam/unreal-engine-mcp — The actor management and procedural world generation (castles, towns, mazes) are ported from this project's Python algorithms.
• CLAUDIUS — The paid plugin that showed what a comprehensive UE5 AI integration should cover. Our new tool categories (Sequencer, Behavior Trees, Navigation, etc.) were inspired by their feature set.