VibeUE: Unreal Engine Vibe Coding Tool

VibeUE, an MCP Expansion and AI Editor Toolset for Unreal Engine 5.8+, adds deep editor capabilities including terrain, audio, animation, Niagara, UMG, Blueprint authoring, and a PerformanceService for diagnosing frame rate issues. The tool complements Unreal's native AI toolsets by focusing on domains the engine does not cover, such as real-world terrain from GPS, Custom-HLSL scratch-pad modules, and performance profiling with Unreal Insights trace analysis. A free API key unlocks real-world terrain tools; everything else works without one.

VibeUE is the MCP Expansion + AI Editor Toolset for Unreal Engine 5.8+. Unreal 5.8 added a built-in MCP server and AI toolsets; VibeUE is an MCP Expansion that plugs straight into them and adds a deep AI Editor Toolset — a library of editor capabilities — Blueprints, materials, landscape, foliage, animation, Niagara, UMG, audio, StateTree, gameplay tags, input, UVs, performance/profiling , and more — registered into the engine's own ToolsetRegistry and ModelContextProtocol server, plus rich domain skills served through Unreal's native AgentSkill system. Any MCP-capable agent Claude Code, Cursor, Copilot, … drives your editor through Unreal's standard MCP endpoint. ⚠️ VibeUE requires Unreal's native MCP to be set up first— enable theUnreal MCPplugin which auto-enablesToolset Registry and theEditor Toolsplugin, then start the MCP server. Follow Epic's guide:. VibeUE then expands that endpoint — Unreal MCP in the Unreal Editor no separate server and no in-editor chat.A free API key set inEditor Preferences → Plugins → VibeUE unlocks the real-worldterraintools; everything else works without one. Unreal 5.8 ships its own AI toolsets Blueprints, materials, actors, assets, meshes, data tables, … . VibeUE complements them — it focuses on the domains and depth the engine doesn't cover: Terrain & world — Landscape sculpting/heightmaps/splines, landscape auto-materials + RVT, Foliage, procedural FPS Map Blockout , and real-world terrain heightmaps + water from GPS . Audio — MetaSound and SoundCue graph authoring. Animation assets — AnimSequence keyframe editing, AnimMontage authoring, AnimBP state machines, Skeleton bone/socket/retarget/blend-profile editing. FX depth — Niagara emitter color/curve authoring and Custom-HLSL scratch-pad modules. UI — UMG widgets with MVVM bindings, animation authoring, and preview/PIE validation. Higher-order Blueprint authoring — timelines, event dispatchers, delegates, custom-event pins, comment boxes, and a batch build graph builder. Editor safety — TransactionService wraps the editor's transaction buffer undo / redo / checkpoints so an agent can group and roll back its own edits — the engine's toolsets expose none. ⚡ Performance & profiling — VibeUE's standout: see the dedicated section below. Python-first access — run any unreal. Python in the editor and introspect the whole API. Web research — search / fetch / geocode for in-context research and terrain workflows. It deliberately does not duplicate the engine's general tools basic asset/actor/blueprint/material CRUD, screenshots, logs, PIE — agents use Unreal's native toolsets for those. Unreal's native AI toolsets have zero performance tooling — they can start PIE/Simulate but can't measure anything. VibeUE's PerformanceService fills that gap so an agent can actually diagnose and fix frame rate: — Game/Render/GPU/RHI thread split + a frame timing CPU-vs-GPU-bound verdict and a concrete next-step hint. Run this first — optimising the GPU does nothing on a CPU-bound frame. Unreal Insights capture — start trace / stop trace / get trace status , with bookmark and region start / region end markers.— reads the trace analyse and log back and returns a perf summary frame stats, worst frames, hitches, notable log lines . Trace-attached — profile a representative standalone build, not just the editor viewport. start standalone python import unreal print unreal.PerformanceService.frame timing CPU vs GPU bound — diagnose FIRST unreal.PerformanceService.start trace "cap", "" Insights trace … reproduce the workload ideally under PIE / standalone … unreal.PerformanceService.stop trace print unreal.PerformanceService.analyse "both", "" Pair with the profiling and frame-rate skills for the full CPU/GPU drill-down. VibeUE plugs into three native UE 5.8+ systems: Toolsets ToolsetRegistry — VibeUE's services register as UToolsetDefinition s, so their methods become AICallable tools on the MCP endpoint. They're also BlueprintCallable , so the same methods are callable from Python as unreal.<Name Service.<method . MCP server ModelContextProtocol — a small set of VibeUE utility tools are registered directly on the endpoint: execute python code , discover python module / class / function , list python subsystems , deep research , terrain data . Skills AgentSkillToolset — ~34 markdown skill packs register as native UAgentSkill s, discoverable via ListSkills and loaded lazily via GetSkills , alongside the engine's own skills. Efficient usage for agents : execute python code is the workhorse — it batches a whole multi-step task into one round-trip and reaches every VibeUE service plus the full unreal. API. Use call tool only for skills and the few engine toolsets with no Python path screenshots, etc. . See Content/samples/AGENTS.md.sample /kevinpbuckley/VibeUE/blob/master/Content/samples/AGENTS.md.sample for the full agent guide. Requirements: Unreal Engine 5.8+ · Git VibeUE is an expansion of Unreal's built-in MCP support, so enable that first. Full details in Epic's guide: Unreal MCP in the Unreal Editor . Edit → Plugins → enable Unreal MCP this auto-enables Toolset Registry and Editor Tools the engine's own AI toolsets, so agents get both . These are Experimental. Restart when prompted. Edit → Editor Preferences → General → Model Context Protocol → enable Auto Start Server or run the console command ModelContextProtocol.StartServer . Default endpoint http://127.0.0.1:8000/mcp port/path configurable . Enabling Tool Search keeps an agent's context small — it sees list toolsets / describe toolset / call tool and loads tools on demand. cd /path/to/YourProject/Plugins git clone https://github.com/kevinpbuckley/VibeUE.git Build with the project script: Plugins/VibeUE/BuildAndLaunchGame.ps1 builds + launches the editor Plugins/VibeUE/BuildAndLaunchGame.ps1 -StrictRebuild full recompile warnings-as-errors On Linux or macOS, use the platform-detecting shell script: Plugins/VibeUE/BuildAndLaunchGame.sh --engine /path/to/UE5 Plugins/VibeUE/BuildAndLaunchGame.sh --engine /path/to/UE5 --strict-rebuild Then Edit → Plugins → enable VibeUE and restart. Its services, tools, and skills now register onto the same endpoint, alongside the engine's own. Two console commands from the editor open the console with : 1. Write the MCP server config .mcp.json at the project root : ModelContextProtocol.GenerateClientConfig ClaudeCode supports ClaudeCode , Cursor , VSCode , Gemini , Codex , or All . 2. Write VibeUE's agent guide so the assistant uses the efficient patterns: VibeUE.GenerateAgentConfig ClaudeCode This writes the guide to the correct file for your agent — CLAUDE.md Claude Code , GEMINI.md Gemini , AGENTS.md Codex / Hermes / Cursor , or .github/copilot-instructions.md Copilot — or pass All to write CLAUDE.md + GEMINI.md + AGENTS.md at once. It resolves the plugin location automatically, so it works whether VibeUE was installed from FAB or Git . The guide goes in a managed block, so re-run any time to refresh without disturbing your own notes. Pass import to link the guide with a one-line @import instead of copying it Claude Code / Gemini only — other agents don't resolve imports, so they always get a copy . The MCP server is loopback-only with no authentication — same-machine use only per Epic's docs . The guide teaches: discover before you call discover python class , batch with execute python code , load skills via ListSkills / GetSkills , and when to reach for deep research / terrain data . Skills are lazy-loaded domain knowledge workflows, gotchas, property formats served by Unreal's native AgentSkillToolset : discover summaries only — cheap call tool tool name="ListSkills", toolset name="ToolsetRegistry.AgentSkillToolset" load the packs you need full markdown, lazy call tool tool name="GetSkills", toolset name="ToolsetRegistry.AgentSkillToolset", arguments={"skillPaths": "/VibeUE/Python/init unreal PY.VibeUE blueprints" } ListSkills is the live source of truth for what's available it reads each pack's SKILL.md . Skills tell you what to do and why ; use discover python class 'unreal.<Name Service', method filter='…' for exact signatures before writing code. Native engine prerequisites enable in Step 1 — Epic's MCP stack : | Plugin | Purpose | |---|---| Unreal MCP ModelContextProtocol | The native MCP server endpoint | Toolset Registry ToolsetRegistry | Native AI toolset + AgentSkill registration auto-enabled by Unreal MCP | Editor Tools EditorToolset | The engine's own AI toolsets — VibeUE complements these | Enabled automatically by VibeUE: PythonScriptPlugin the unreal. API , EditorScriptingUtilities , and the domain plugins its services need — Niagara , MetaSound , EnhancedInput , ModelViewViewModel , StateTree , MeshModelingToolset , GameplayTagsEditor . VibeUE also depends on ToolsetRegistry + ModelContextProtocol , so enabling VibeUE pulls them in — but you still enable Editor Tools and start the server per Step 1. BuildAndLaunchGame.ps1 project root or Plugins/VibeUE/ stops the running editor, builds, and relaunches: -StrictRebuild — full plugin recompile under warnings-as-errors -Clean — wipe intermediate/binaries first -SkipBuild — relaunch only VibeUE intentionally keeps no static method catalog in this README — the surface evolves with the engine. The authoritative, always-current references are: → which domains exist and when to use them. ListSkills → exact method signatures. discover python class 'unreal.<Name Service' → the toolset's tools + JSON schemas token-heavy; prefer skills + discovery . describe toolset 'VibeUE.<Name Service' MIT — see LICENSE /kevinpbuckley/VibeUE/blob/master/LICENSE . Project home: https://www.vibeue.com/ https://www.vibeue.com/