
Description
Connect Claude Code, Cursor, Windsurf, Claude Desktop, VS Code (Copilot), Antigravity, OpenCode, or any MCP-compatible AI agent directly to the Unreal Engine 5.7 Editor.
The v4 release ships 378 editor tools across 54 categories, plus 15 context resources and 14 workflow prompts via JSON-RPC 2.0 over Streamable HTTP β turning your AI assistant into a true co-developer for level building, gameplay scripting, cinematics, VFX, audio, networking, animation, UI, source control, automated testing, runtime debugging, modeling, material layers, Chaos destruction, and MetaHumans.
π¬ Video Showcase https://www.youtube.com/watch?v=wEuaFqUPp00
π What's New in v4 (vs v3) v4 is the agent-native release β rebuilt around how AI agents actually work. Same workflow, far cheaper context, far safer multi-step editing.
Catalog mode (default) β ~95% less agent context
tools/list returns 4 discovery meta-tools + ~30 core tools (~3K tokens) instead of all 378 schemas (~60K tokens). Agents discover the rest on demand via search_tools, list_tool_categories, and get_tool_schemas. Everything stays callable. Set ToolExposureMode = Full for the old behavior.
run_tool_script β multi-step programs as one transaction
Sequential tool calls with result references (save_as / "$var.field") and foreach loops, executed in ONE editor transaction (all-or-nothing, rolled back on first failure). A 24-actor level blockout becomes a single call and a single Ctrl+Z β killing the N-round-trip problem for batch work.
Background tasks β long ops no longer block
Long-running tools (lighting/nav builds, fracture, remesh, PCG execute, fal.ai generation, automation runs) return {task_id, status: "working"} after a 3s grace window. Poll get_task_status for progress, abort with cancel_task, enumerate with list_tasks. Implemented as tools, so every MCP client works without capability negotiation.
Closed-loop graph editing β agents verify their own edits
describe_graph returns full Blueprint topology (nodes + pins + deduplicated edge list + compile status) in ONE call, replacing NΓget_node_pins round-trips. Plus get_execution_paths, move_node, delete_nodes, comments, reroutes, find_orphaned_nodes, list_node_types, and list_actor_components / get_component_info.
Modeling & Chaos are now real (were schema stubs in v3)
Modeling (5): polyextrude, polycut, boolean, uv_unwrap, remesh β implemented via GeometryScript, with before/after triangle counts.
Chaos: chaos_create_geometry_collection and chaos_fracture (voronoi / cluster / uniform / planar) now execute for real; chaos_apply_force applies runtime impulses.
Structured output everywhere
Every JSON-returning tool ships structuredContent alongside human-readable text. Structured errors carry a machine-readable {code, hint, did_you_mean[]} β agents switch on code for recovery flows instead of regexing strings, cutting retry loops dramatically.
Universal undo
Every mutating tool now runs inside its own named MCP: <tool> editor transaction. Ctrl+Z works as expected; multi-step scripts collapse into one undo step.
Hardened core
Request body size limit (HTTP 413 before parsing), tool-call timeouts (structured timeout error), exception guards (a throwing tool returns a structured internal error instead of crashing the editor), idle-session garbage collection, a real BindAddress setting, and DNS-rebinding defense via Host-header validation.
Quality guarded by a registry-wide test matrix
MatrixSpec generates contract tests over the ENTIRE registry. New tools are covered the moment they register; it caught a v3 editor crash and 5 silent bugs during development. export_tool_docs regenerates the per-tool reference from the live registry so docs can't drift.
Redesigned status bar
π Key Features
378 Editor Tools across 54 categories β Actors, Materials, Material Layers/Graph, Blueprints, Sequencer, Landscapes, Foliage, Niagara, Audio, MetaSounds, MetaSound Graph, Physics, Chaos, Navigation, PCG, GAS, Enhanced Input, Networking, AI Behavior Trees, AnimGraph, StateTree, Control Rig, CommonUI, AI 3D/Image gen, Source Control, Test Authoring, Runtime Debug, PIE, Modeling, MetaHuman, plus the v4 Meta/Tasks discovery layer.
Catalog Mode β progressive tool disclosure cuts a fresh session's tool-definition cost ~95% (~3K vs ~60K tokens) while keeping all 378 tools callable.
Tool Presets β Full / Scene Building / Gameplay / Minimal / Catalog. Switch instantly to manage AI context cost.
Multi-step tool scripts β run_tool_script runs a sequence (with variables and loops) as ONE all-or-nothing editor transaction.
Full Undo Support β every mutating operation is its own named editor transaction; scripts collapse into one undo step.
Universal AI Compatibility β Claude Code, Claude Desktop, Cursor, VS Code (Copilot), Windsurf, Antigravity, OpenCode, and any MCP-compatible client. Streamable HTTP + SSE β no vendor lock-in.
15 Context Resources β project data, level hierarchy, selected actors, performance stats, capability detection, undo history, and more.
60 Blueprint Tools β components, variables, wire nodes, set properties, full graph read-back, exec-path tracing, and cleanup.
Source Control Aware β works against any provider Unreal supports (Perforce, Git LFS, Plastic, Subversion).
Production-grade safety β bearer-token auth, origin allow-list, scope gating, structured errors, cooperative cancellation, dry-run, request size limits, tool-call timeouts, exception guards, session GC, DNS-rebinding defense.
π¦ What's Included
Full C++ source code with extensible architecture
378 tools across 54 categories
5 tool presets (Full / Scene Building / Gameplay / Minimal / Catalog)
15 read-only context resources
14 reusable workflow prompts
AI-powered image generation and text/image-to-3D via fal ai
STDIO bridge for non-HTTP clients (Claude Desktop)
Live status bar indicator with one-click Copy Claude Code Config
Bearer-token auth, origin allow-list, scope gating, rate limiting
Registry-generated tool reference (export_tool_docs) and comprehensive documentation
π§© Tool Categories (54) Core β Actor (16), Editor (7), Asset (6), Level (6), Asset Management (7), Batch (3) Scene Building β Material (5), Material Graph (8), Material Layers (4), Static Mesh (7), Environment (4), Modeling (5) Scripting β Blueprint (60), Python Bridge (1), Search (2) Cinematic β Sequencer (12), Animation (5), Anim Graph (14), Control Rig (2) World Building β Landscape (3), Foliage (4), Spline (7), World Partition (2), Spatial (10), PCG (9) VFX & Audio β Niagara (3), Audio (3), MetaSound (6), MetaSound Graph (8) Simulation β Physics (9), Navigation (3), Chaos (5) Characters β MetaHuman (4) Data β Data Tools (6) UI β Widget/UMG (15), CommonUI (4), UI Image (2) Gameplay β GAS (8), Enhanced Input (6), Game Framework (6), Gameplay Tags (3), State Tree (5), PIE (9) Networking β Networking (5) AI β AI Tools (8), 3D Model (3) DevOps β Source Control (8), Test Authoring (5), Runtime Debug (7) Workflow β Macro (6), Build (7), Engine API (3), Performance (4) Agent (v4) β Meta & Tasks (8)
π Plugin Dependencies (auto-enabled) EditorScriptingUtilities, Niagara, PCG, EnhancedInput, SourceControl, FunctionalTesting, GeometryScripting, Fracture, GameplayAbilities (optional), PythonScriptPlugin (optional)
βοΈ Technical Specs
Protocol: MCP spec 2025-06-18, Streamable HTTP
Transport: JSON-RPC 2.0 over HTTP (default port 13579) + SSE fallback
Engine Support: Unreal Engine 5.7 (Windows, macOS, Linux)
Threading: All UE API calls automatically dispatched to the game thread
Source Code: Full C++ access included
Auth: Bearer-token + origin allow-list (localhost-only by default)
Documentation: https://www.strayspark.studio/docs/unreal-mcp-server





