MCP Tools Reference

All tools are available in Claude Code mode only. They are exposed via the local MCP server and called automatically by Claude when it needs project information or wants to make changes.

Tools return a JSON object with ok: true/false and either a payload (success) or error (failure) field.

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Read-only tools

These tools never modify anything. They do not trigger confirmation dialogs.

ping

Test that the MCP connection is alive.

get_active_context

Returns the type, name, and asset path of the currently focused editor tab.

{
  "ok": true,
  "payload": {
    "type": "Blueprint",
    "name": "BP_Character",
    "path": "/Game/Characters/BP_Character"
  }
}

Possible types: Blueprint, DataTable, Other

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list_blueprint_variables

Lists all member variables of the focused Blueprint.

Returns per variable:

• name — variable name
• type — CPP type string (e.g. bool, int32, FString, UStaticMeshComponent*)
• category — editor category
• default — default value
• is_used — whether the variable is referenced anywhere in the graph

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list_blueprint_functions

Lists all function graphs, macro graphs, and event graphs in the focused Blueprint.

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get_graph_nodes

Parameter	Type	Default	Description
graph_name	string	EventGraph	Name of the graph to read

Returns all nodes in the specified graph with their node type, title, and ID.

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get_node_details

Parameter	Type	Description
node_id	string	Node GUID from get_graph_nodes

Returns full details for a single node: all pins, links, and default values.

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get_data_table_struct

Returns the schema of the focused DataTable's row struct: field names, types, and tooltips.

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list_data_table_rows

Parameter	Type	Default	Description
page	int	0	Page index
page_size	int	100	Rows per page (max 1000)

Returns DataTable rows as JSON objects.

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get_data_table_row

Parameter	Type	Description
row_name	string	Row name (FName) to retrieve

Returns a single row as a JSON object.

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Destructive tools

These tools modify your project. Unless Auto-approve MCP tools is enabled in settings, each call shows a confirmation dialog before executing.

Undo support

Blueprint variable operations register an undo transaction — you can Ctrl+Z them. DataTable operations and Python scripts may not be fully reversible.

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add_variable

Parameter	Type	Description
name	string	New variable name
type	string	Type string (e.g. bool, int32, FVector)
category	string	(optional) Editor category
default_value	string	(optional) Default value

Creates a new member variable in the focused Blueprint.

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rename_variable

Parameter	Type	Description
old_name	string	Current variable name
new_name	string	New variable name

Renames the variable and updates all references in the graph automatically.

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delete_variable

Parameter	Type	Description
name	string	Variable name to delete

Deletes the variable. Confirmation required.

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delete_unused_variables

Finds all unreferenced variables and presents them for review before deleting.

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set_variable_metadata

Parameter	Type	Description
name	string	Variable name
tooltip	string	(optional) New tooltip text
category	string	(optional) New category

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add_data_table_row

Parameter	Type	Description
row_name	string	FName for the new row
row_data	object	JSON object matching the row struct

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add_data_table_rows_batch

Parameter	Type	Description
rows	array	Array of {row_name, row_data} objects

Adds multiple rows in one operation.

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update_data_table_row

Parameter	Type	Description
row_name	string	Row to update
row_data	object	Fields to set (partial update supported)

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rename_data_table_row

Parameter	Type	Description
old_name	string	Current row name
new_name	string	New row name

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delete_data_table_row

Parameter	Type	Description
row_name	string	Row to delete

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rearrange_graph

Parameter	Type	Description
graph_name	string	Graph to rearrange
layout	array	Array of {node_id, x, y} position objects

Repositions nodes in the Blueprint graph.

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add_comment

Parameter	Type	Description
graph_name	string	Target graph
comment	string	Comment text
x, y	number	Position in graph
width, height	number	Comment box size

Adds a comment node to the Blueprint graph.

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run_python

Parameter	Type	Description
script	string	Python code to execute via Unreal's Python Script Plugin

Executes arbitrary Python in the Unreal Python environment. Has access to unreal module and all its APIs.

Powerful and irreversible

run_python can do anything the Python Script Plugin can do — including deleting assets, modifying levels, and writing files. Use confirmation dialogs or auto-approve sparingly.