unreal_blueprints

The unreal_blueprints tool provides full programmatic access to Blueprint authoring — listing and inspecting Blueprints, reading graph topology, adding variables and functions, placing nodes, wiring pins, and setting default values. It exposes 10 operations.

Operations at a Glance

Operation	Hint	Description
`list`	readOnly	List all Blueprints in a content directory
`inspect`	readOnly	Get full variable and component list for a Blueprint
`get_graph`	readOnly	Return all nodes and connections in a named graph
`get_events`	readOnly	List all event nodes in a Blueprint
`create`	—	Create a new Blueprint (alias for unreal_assets create_blueprint)
`add_variable`	—	Add a typed variable to a Blueprint
`add_function`	—	Add a new function graph to a Blueprint
`add_node`	—	Add a node to a Blueprint graph
`connect_pins`	—	Connect two pins between nodes
`set_pin_value`	idempotent	Set the default value of a node pin

list

Lists all Blueprint assets in a content directory.

Parameters

Parameter	Type	Required	Description
`path`	string	yes	Content directory to search, e.g. `/Game/Characters/`
`recursive`	boolean	no	Include subdirectories. Default: false.
`parent_class`	string	no	Filter by parent class name

{
  "operation": "list",
  "params": {
    "path": "/Game/Characters/",
    "recursive": true
  }
}

{
  "operation": "list",
  "params": {
    "path": "/Game/",
    "recursive": true,
    "parent_class": "Character"
  }
}

inspect

Returns the full structure of a Blueprint — variables, components, functions, event graphs, and parent class chain.

Parameters

Parameter	Type	Required	Description
`path`	string	yes	Full content path of the Blueprint

{
  "operation": "inspect",
  "params": {
    "path": "/Game/Characters/Enemies/BP_Enemy_Goblin"
  }
}

Response

{
  "name": "BP_Enemy_Goblin",
  "parent_class": "/Script/Engine.Character",
  "variables": [
    { "name": "MaxHealth", "type": "float", "default": 100.0, "access": "public" },
    { "name": "AggroRange", "type": "float", "default": 800.0, "access": "public" },
    { "name": "bIsAggro", "type": "bool", "default": false, "access": "private" }
  ],
  "components": [
    { "name": "CapsuleComponent", "class": "CapsuleComponent" },
    { "name": "SkeletalMeshComponent", "class": "SkeletalMeshComponent" },
    { "name": "CharacterMovement", "class": "CharacterMovementComponent" }
  ],
  "functions": ["TakeDamage", "OnDeath", "BeginAggro"],
  "event_graphs": ["EventGraph"],
  "interfaces": ["BPI_Damageable"]
}

get_graph

Returns all nodes and pin connections in a specific Blueprint graph.

Parameters

Parameter	Type	Required	Description
`path`	string	yes	Full content path of the Blueprint
`graph`	string	yes	Graph name, e.g. `EventGraph`, `BeginPlay`, or a function name

{
  "operation": "get_graph",
  "params": {
    "path": "/Game/Characters/Enemies/BP_Enemy_Goblin",
    "graph": "EventGraph"
  }
}

Response

{
  "graph": "EventGraph",
  "nodes": [
    {
      "id": "node_0",
      "type": "K2Node_Event",
      "name": "Event BeginPlay",
      "position": { "x": -400, "y": 0 },
      "pins": [
        { "name": "then", "direction": "output", "type": "exec" }
      ]
    },
    {
      "id": "node_1",
      "type": "K2Node_CallFunction",
      "name": "SetActorHiddenInGame",
      "position": { "x": -100, "y": 0 },
      "pins": [
        { "name": "execute", "direction": "input", "type": "exec" },
        { "name": "then", "direction": "output", "type": "exec" },
        { "name": "bNewHidden", "direction": "input", "type": "bool", "default_value": "false" }
      ]
    }
  ],
  "connections": [
    { "from_node": "node_0", "from_pin": "then", "to_node": "node_1", "to_pin": "execute" }
  ]
}

get_events

Lists all event nodes across all graphs in a Blueprint.

Parameters

Parameter	Type	Required	Description
`path`	string	yes	Full content path of the Blueprint

{
  "operation": "get_events",
  "params": {
    "path": "/Game/Characters/Enemies/BP_Enemy_Goblin"
  }
}

Response

{
  "events": [
    { "name": "Event BeginPlay", "graph": "EventGraph", "node_id": "node_0" },
    { "name": "Event Tick", "graph": "EventGraph", "node_id": "node_4" },
    { "name": "Event TakeDamage", "graph": "EventGraph", "node_id": "node_12" }
  ]
}

create

Creates a new Blueprint class. This is an alias for unreal_assets / create_blueprint and uses the same parameters.

Parameters

Parameter	Type	Required	Description
`path`	string	yes	Destination content path including asset name
`parent_class`	string	yes	Parent class path

{
  "operation": "create",
  "params": {
    "path": "/Game/Items/BP_Weapon_Sword",
    "parent_class": "/Script/Engine.Actor"
  }
}

add_variable

Adds a new variable to a Blueprint. Supports all UE variable types.

Parameters

Parameter	Type	Required	Description
`path`	string	yes	Full content path of the Blueprint
`name`	string	yes	Variable name (no spaces, PascalCase recommended)
`type`	string	yes	Variable type. See type list below.
`default_value`	any	no	Default value for the variable
`access`	string	no	`public`, `protected`, or `private`. Default: `private`.
`instance_editable`	boolean	no	Expose to instance details panel. Default: false.
`blueprint_readonly`	boolean	no	Show in panel but not editable. Default: false.

Supported Types

Type String	UE Type
`bool`	Boolean
`int`	Integer
`float`	Float
`string`	String
`name`	Name
`text`	Text
`vector`	FVector
`rotator`	FRotator
`transform`	FTransform
`object`	Object reference (requires `object_class`)
`class`	Class reference
`array<float>`	TArray<float> (prefix any type with `array<>`)

{
  "operation": "add_variable",
  "params": {
    "path": "/Game/Characters/Enemies/BP_Enemy_Goblin",
    "name": "AggroRange",
    "type": "float",
    "default_value": 800.0,
    "access": "public",
    "instance_editable": true
  }
}

{
  "operation": "add_variable",
  "params": {
    "path": "/Game/Characters/BP_Player",
    "name": "Inventory",
    "type": "array<object>",
    "object_class": "/Game/Items/BP_ItemBase"
  }
}

add_function

Creates a new function graph in a Blueprint.

Parameters

Parameter	Type	Required	Description
`path`	string	yes	Full content path of the Blueprint
`name`	string	yes	Function name (PascalCase recommended)
`inputs`	array	no	Input parameters. Each: `{ name, type }`
`outputs`	array	no	Output parameters. Each: `{ name, type }`
`access`	string	no	`public`, `protected`, or `private`. Default: `public`.
`pure`	boolean	no	If true, creates a pure (no exec pin) function. Default: false.

{
  "operation": "add_function",
  "params": {
    "path": "/Game/Characters/Enemies/BP_Enemy_Goblin",
    "name": "CalculateDamage",
    "inputs": [
      { "name": "BaseDamage", "type": "float" },
      { "name": "ArmorValue", "type": "float" }
    ],
    "outputs": [
      { "name": "FinalDamage", "type": "float" }
    ],
    "access": "public"
  }
}

Response

{
  "function": "CalculateDamage",
  "graph": "CalculateDamage",
  "entry_node_id": "node_0",
  "return_node_id": "node_1"
}

add_node

Places a Blueprint node in a graph. The node type determines what kind of node is placed.

Parameters

Parameter	Type	Required	Description
`path`	string	yes	Full content path of the Blueprint
`graph`	string	yes	Target graph name
`node_type`	string	yes	Node type identifier (see common types below)
`position`	object	no	`{ x, y }` position in the graph canvas
`params`	object	no	Node-specific configuration (varies by type)

Common Node Types

`node_type`	Description	Key `params` fields
`function_call`	Call a function	`function` (full path or name)
`variable_get`	Read a variable	`variable`
`variable_set`	Write a variable	`variable`
`branch`	If/Else branch	—
`sequence`	Sequential execution	`num_outputs`
`for_each`	Array iteration	—
`cast`	Cast to class	`class`
`event`	Custom event	`event_name`
`macro`	Macro instance	`macro`
`comment`	Comment box	`text`, `width`, `height`

{
  "operation": "add_node",
  "params": {
    "path": "/Game/Characters/Enemies/BP_Enemy_Goblin",
    "graph": "CalculateDamage",
    "node_type": "function_call",
    "params": {
      "function": "FMath::Clamp"
    },
    "position": { "x": 200, "y": 0 }
  }
}

{
  "operation": "add_node",
  "params": {
    "path": "/Game/Characters/Enemies/BP_Enemy_Goblin",
    "graph": "EventGraph",
    "node_type": "variable_get",
    "params": {
      "variable": "MaxHealth"
    },
    "position": { "x": -200, "y": 100 }
  }
}

Response

{
  "node_id": "node_7",
  "node_type": "function_call",
  "position": { "x": 200, "y": 0 },
  "pins": [
    { "name": "execute",  "direction": "input",  "type": "exec" },
    { "name": "then",     "direction": "output", "type": "exec" },
    { "name": "Value",    "direction": "input",  "type": "float" },
    { "name": "Min",      "direction": "input",  "type": "float" },
    { "name": "Max",      "direction": "input",  "type": "float" },
    { "name": "ReturnValue", "direction": "output", "type": "float" }
  ]
}

connect_pins

Wires two pins together. Both nodes must already exist in the same graph.

Parameters

Parameter	Type	Required	Description
`path`	string	yes	Full content path of the Blueprint
`graph`	string	yes	Graph containing both nodes
`from_node`	string	yes	Source node ID
`from_pin`	string	yes	Source pin name
`to_node`	string	yes	Destination node ID
`to_pin`	string	yes	Destination pin name

{
  "operation": "connect_pins",
  "params": {
    "path": "/Game/Characters/Enemies/BP_Enemy_Goblin",
    "graph": "EventGraph",
    "from_node": "node_0",
    "from_pin": "then",
    "to_node": "node_1",
    "to_pin": "execute"
  }
}

Note: Pin types must be compatible. Connecting an exec pin to a data pin will return a validation error. Use get_graph to retrieve pin names and types before connecting.

set_pin_value

Sets the default (literal) value of a node's input pin. This sets the inline value shown in the graph when no wire is connected to the pin.

Parameters

Parameter	Type	Required	Description
`path`	string	yes	Full content path of the Blueprint
`graph`	string	yes	Graph containing the node
`node`	string	yes	Node ID
`pin`	string	yes	Pin name
`value`	any	yes	The literal value to set

{
  "operation": "set_pin_value",
  "params": {
    "path": "/Game/Characters/Enemies/BP_Enemy_Goblin",
    "graph": "CalculateDamage",
    "node": "node_7",
    "pin": "Min",
    "value": 0.0
  }
}

{
  "operation": "set_pin_value",
  "params": {
    "path": "/Game/Characters/Enemies/BP_Enemy_Goblin",
    "graph": "CalculateDamage",
    "node": "node_7",
    "pin": "Max",
    "value": 999.0
  }
}

Complete Workflow: Blueprint From Scratch

This example creates a health component Blueprint end-to-end.

// 1. Create the Blueprint
await create({
  path: "/Game/Components/BP_HealthComponent",
  parent_class: "/Script/Engine.ActorComponent"
})

// 2. Add variables (can parallelize — different variable names)
await parallel([
  add_variable({ path: "...", name: "MaxHealth",     type: "float", default_value: 100.0, instance_editable: true }),
  add_variable({ path: "...", name: "CurrentHealth", type: "float", default_value: 100.0 }),
  add_variable({ path: "...", name: "bIsDead",       type: "bool",  default_value: false }),
])

// 3. Add function
const fn = await add_function({
  path: "/Game/Components/BP_HealthComponent",
  name: "ApplyDamage",
  inputs:  [{ name: "DamageAmount", type: "float" }],
  outputs: [{ name: "bKilled", type: "bool" }]
})

// 4. Place nodes in the function graph
const subNode = await add_node({
  path: "...", graph: "ApplyDamage",
  node_type: "function_call",
  params: { function: "FMath::Max" },
  position: { x: 200, y: 0 }
})

const setNode = await add_node({
  path: "...", graph: "ApplyDamage",
  node_type: "variable_set",
  params: { variable: "CurrentHealth" },
  position: { x: 500, y: 0 }
})

// 5. Wire them
await connect_pins({
  path: "...", graph: "ApplyDamage",
  from_node: fn.entry_node_id, from_pin: "then",
  to_node: subNode.node_id,    to_pin: "execute"
})

await connect_pins({
  path: "...", graph: "ApplyDamage",
  from_node: subNode.node_id, from_pin: "ReturnValue",
  to_node: setNode.node_id,   to_pin: "CurrentHealth"
})

// 6. Set literal values
await set_pin_value({ path: "...", graph: "ApplyDamage", node: subNode.node_id, pin: "B", value: 0.0 })

// 7. Save
await unreal_assets.save({ paths: ["/Game/Components/BP_HealthComponent"] })