Ue5 Gamedev

Project path: Set UE5_PROJECT_PATH to your .uproject directory (e.g., D:\UnrealProjects\MyGame).

C++ coding standards

Follow Epic's conventions strictly:

Naming prefixes

• F -- Structs (FVector, FHitResult, FMyStruct)
• U -- UObject-derived classes (UActorComponent, UMyComponent)
• A -- Actor-derived classes (ACharacter, AMyActor)
• E -- Enums (ECollisionChannel, EMyEnum)
• I -- Interfaces (IInteractable)
• T -- Templates (TArray, TMap, TSubclassOf)
• b -- Boolean variables (bIsAlive, bCanJump)

UPROPERTY specifiers

// Editable in editor, visible in Blueprints
UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Combat")
float MaxHealth = 100.f;

// Set in Blueprint, read-only in editor
UPROPERTY(VisibleAnywhere, BlueprintReadOnly, Category = "Status")
bool bIsAlive = true;

// Replicated property
UPROPERTY(ReplicatedUsing = OnRep_Health)
float Health;

// Not exposed, internal only
UPROPERTY()
float InternalTimer;

UFUNCTION specifiers

// Callable from Blueprints
UFUNCTION(BlueprintCallable, Category = "Combat")
void TakeDamage(float Amount);

// Implementable in Blueprints (no C++ body)
UFUNCTION(BlueprintImplementableEvent, Category = "Events")
void OnDeath();

// C++ default with Blueprint override option
UFUNCTION(BlueprintNativeEvent, Category = "Events")
void OnHit(const FHitResult& Hit);

// Server RPC
UFUNCTION(Server, Reliable, WithValidation)
void ServerFireWeapon();

Container types

• TArray<T> -- Dynamic array (not std::vector)
• TMap<K, V> -- Hash map (not std::map)
• TSet<T> -- Hash set
• TSubclassOf<T> -- Type-safe class reference
• TSoftObjectPtr<T> -- Lazy-loaded asset reference
• TWeakObjectPtr<T> -- Non-owning reference

Rules

• No raw new/delete -- use NewObject<T>(), CreateDefaultSubobject<T>(), or smart pointers
• Use FString, FName, FText -- never std::string
• Keep functions under 50 lines
• Use const correctness everywhere
• Document all public interfaces with /** */ comments
• Use #pragma once (not include guards)
• Include "CoreMinimal.h" first, then project headers

Gameplay framework classes

Remote Control API

The Remote Control API plugin exposes UE5 editor functionality over HTTP.

Read a property

PUT http://localhost:8080/remote/object/property
{
  "objectPath": "/Game/Maps/MainLevel.MainLevel:PersistentLevel.BP_Player_C_0",
  "propertyName": "MaxHealth"
}

Set a property

PUT http://localhost:8080/remote/object/property
{
  "objectPath": "/Game/Maps/MainLevel.MainLevel:PersistentLevel.BP_Player_C_0",
  "propertyName": "MaxHealth",
  "propertyValue": { "MaxHealth": 200.0 }
}

Call a function

PUT http://localhost:8080/remote/object/call
{
  "objectPath": "/Game/Maps/MainLevel.MainLevel:PersistentLevel.BP_Player_C_0",
  "functionName": "TakeDamage",
  "parameters": { "Amount": 50.0 }
}

Search for objects

PUT http://localhost:8080/remote/search/object
{
  "query": "BP_Player",
  "class": "/Script/Engine.Actor",
  "outerPath": "/Game/Maps/MainLevel"
}

Execute console command

PUT http://localhost:8080/remote/object/call
{
  "objectPath": "/Script/Engine.Default__KismetSystemLibrary",
  "functionName": "ExecuteConsoleCommand",
  "parameters": {
    "WorldContextObject": "/Game/Maps/MainLevel.MainLevel",
    "Command": "stat fps"
  }
}

Python bridge

UE5's Python Editor Script Plugin exposes the unreal module inside the editor. Execute Python remotely via port 30010.

Common operations

import unreal

# Get the editor subsystem
editor = unreal.EditorLevelLibrary()

# Spawn an actor
location = unreal.Vector(0, 0, 100)
rotation = unreal.Rotator(0, 0, 0)
actor = editor.spawn_actor_from_class(unreal.StaticMeshActor, location, rotation)

# Set a mesh
mesh_component = actor.get_component_by_class(unreal.StaticMeshComponent)
mesh = unreal.EditorAssetLibrary.load_asset("/Engine/BasicShapes/Cube")
mesh_component.set_static_mesh(mesh)

# Find actors
actors = unreal.EditorLevelLibrary.get_all_level_actors()
player_starts = unreal.GameplayStatics.get_all_actors_of_class(
    unreal.EditorLevelLibrary.get_editor_world(),
    unreal.PlayerStart
)

# Asset operations
unreal.EditorAssetLibrary.rename_asset("/Game/Old/Path", "/Game/New/Path")
unreal.EditorAssetLibrary.duplicate_asset("/Game/Source", "/Game/Copy")
unreal.EditorAssetLibrary.delete_asset("/Game/Unused/Asset")

# Blueprint operations
factory = unreal.BlueprintFactory()
factory.set_editor_property("parent_class", unreal.Actor)
asset_tools = unreal.AssetToolsHelpers.get_asset_tools()
blueprint = asset_tools.create_asset("BP_MyActor", "/Game/Blueprints", None, factory)

Remote execution from external script

# Uses UE5's remote_execution.py (bundled with Python Editor Script Plugin)
# Or use the upyrc package: pip install upyrc
import remote_execution

remote = remote_execution.RemoteExecution()
remote.start()
# Wait for node discovery
nodes = remote.remote_nodes
# Execute on first found editor
remote.run_command("print('Hello from external!')", exec_node=nodes[0])
remote.stop()

UE5 Bridge API (optional orchestrator / proxy)

If you run a bridge or orchestrator service that proxies commands to the UE5 editor host, configure it with UE5_BRIDGE_HOST. This is useful when the machine running Claude Code is not the same machine running UE5, or when you want centralized command routing.

Example endpoints (adjust host/port to your setup):

# Check UE5 connectivity
GET http://localhost:8000/ue5/status

# Trigger a build
POST http://localhost:8000/ue5/build
{
  "project_path": "D:\\UnrealProjects\\MyGame",
  "config": "Development",
  "platform": "Win64",
  "cook_content": true
}

# Check build status
GET http://localhost:8000/ue5/build/{job_id}

# Execute editor command
POST http://localhost:8000/ue5/editor/command
{ "command": "open_level", "args": {"level": "/Game/Maps/MainLevel"} }

# List assets
GET http://localhost:8000/ue5/assets?path=/Game&asset_type=Blueprint

# Import asset
POST http://localhost:8000/ue5/import
{
  "source_path": "\\\\server\\exports\\character.fbx",
  "destination_path": "/Game/Characters/Imported"
}

Open-source MCP servers

These MCP servers provide additional UE5 integration capabilities:

ChiR24/Unreal_mcp (recommended)

Native C++ automation bridge.

• Install: npm install -g unreal-engine-mcp-server
• Capabilities: Actor creation/manipulation, asset management, Blueprint operations, lighting control, animation sequencing, audio management, console commands
• Architecture: TypeScript server + C++ UE integration
• Repo: https://github.com/ChiR24/Unreal_mcp

chongdashu/unreal-mcp

Remote Control API based. Includes a pre-configured UE5.5 starter project.

• Capabilities: Create/delete actors, set transforms, query properties, create Blueprint classes, add components, configure input mappings
• Repo: https://github.com/chongdashu/unreal-mcp

appleweed/UnrealMCPBridge

Direct Python API access via MCP. Available on Fab Store.

• Capabilities: Full unreal Python module access through MCP
• Setup: Install plugin, click "Start MCP Bridge" toolbar button (socket on 127.0.0.1:9000)
• Repo: https://github.com/appleweed/UnrealMCPBridge

ayeletstudioindia/unreal-analyzer-mcp

Source code analysis and understanding (read-only).

• Capabilities: Class analysis, inheritance mapping, code search, reference finding, pattern detection
• Tech: TypeScript + Tree-sitter C++ parsing
• Repo: https://github.com/ayeletstudioindia/unreal-analyzer-mcp

Blueprint best practices

When creating or modifying Blueprints:

• Keep logic in C++, expose to Blueprints: Use BlueprintCallable for functions, BlueprintReadWrite/BlueprintReadOnly for properties
• Use BlueprintNativeEvent for functions that designers should be able to override
• Use BlueprintImplementableEvent for pure designer hooks (no C++ implementation)
• Prefer components over inheritance: Attach behavior via UActorComponent subclasses
• Use Data Assets for configuration data (not hardcoded values in Blueprints)
• Use Gameplay Tags instead of enums for extensible categorization
• Use Gameplay Abilities (GAS) for complex ability systems
• Blueprint interfaces for cross-Blueprint communication (not casting)

Build workflow

1. Check UE5 status: GET /ue5/status -- ensure editor is running
2. Save all: Execute editor command to save before building
3. Trigger build: POST /ue5/build with desired config
4. Monitor: Poll GET /ue5/build/{job_id} for status
5. Configs: Development (debug), DebugGame (optimized+debug), Shipping (release)

Troubleshooting

• Can't connect to UE5 host: Check network connectivity, verify UE5 is running, test curl http://localhost:8080/status
• Remote Control not responding: Ensure Remote Control API + Web Remote Control plugins are enabled in the project
• Python bridge timeout: Editor may be busy (compiling shaders, loading level). Retry after delay.
• Build failures: Check build logs on the UE5 host. Common issues: missing includes, GENERATED_BODY() macro, circular dependencies.