Basic Blueprint Debug MCP — Free AI Debugging for Unreal Engine

Give your AI agent (TRAE, Claude, Cursor…) hands-on control of the Unreal Editor blueprint debugger.

Basic Blueprint Debug MCP is a self-contained MCP (Model Context Protocol) server that exposes the core blueprint debugging tools of the Unreal Engine editor to AI agents.

18 MCP tools included

• PIE lifecycle — start_pie / stop_pie / pause_pie / resume_pie

• Stepping — step_over / step_into / step_out

• Breakpoints — set_breakpoint / delete_breakpoint / set_breakpoint_enabled / list_breakpoints

• Context inspection — get_breakpoint_context / get_call_stack / get_debug_state

• Object tools — get_instances_of_class / get_property_value / set_property_value

• Introspection — get_usage_guide

Every tool stays usable while PIE is running — and even while the debugger is paused at a breakpoint — so an agent can inspect local variables, read/write object properties, set breakpoints and step through your graph at the exact spot where you're stopped, without you touching the editor.

Getting started

1. Enable the plugin, then open Project Settings → Plugins → Basic Blueprint Debug MCP, enable the server and set a port (default 18233)

2. Point your MCP client at the streamable HTTP endpoint: http://127.0.0.1:18233/mcp

   Configuration example:

   {

   "mcpServers": {

   "unreal-blueprint-debug": {

   "url": "http://127.0.0.1:18233/mcp"

   }

   }

   }

3. Call get_usage_guide and start debugging by just talking to your agent

C++ API: FBasicDebugMCPApi exposes every tool as a static function returning JSON — reuse the same logic in your own automation or MCP server without HTTP.

Requirements: Unreal Engine 5.1+, Windows 64-bit.

Looking for more?

Basic Blueprint Debug MCP is a subset of the Advanced Blueprint Debug Suite — the full suite adds:

• Visual blueprint expression evaluation — build expressions as graphs and evaluate them in real time during PIE, referencing PIE world instances and breakpoint local variables

• Conditional breakpoints for blueprint — interrupt only when a condition is true; hit counting ("stop on the 300th loop iteration")

• Parameterized PIE launch — launch to a specified map with attached parameters, named presets, map whitelist/blacklist filtering

• 40+ MCP tools — expression management/evaluation, graph editing, condition attachment, PIE launch configuration, and more, all usable even during breakpoint interruptions