Rekall — AI Coding Assistant Plugin for Unreal Engine
Give your AI assistant real creative power inside the editor. Rekall is a native C++ MCP server that runs inside the Unreal Engine editor and exposes 480+ tools to AI agents — Claude Code, Cursor, Windsurf, or any MCP-compatible client. Your AI doesn't just suggest code: it authors Blueprints, materials, levels, animations, PCG graphs, and complete game systems in real time, while you watch it happen in your editor.
No Python bridge. No Node.js sidecar. No external process. Pure C++ in-engine on 127.0.0.1:30080, running on the editor thread with full UObject access.
What your AI agent can do
Blueprints — create classes, add variables/functions/components, wire event graphs, compile and verify
Materials — author shader graphs node-by-node, set material instance parameters, validate at compile time
Levels & Actors — spawn, transform, destroy actors; configure component defaults; place lights, cameras, post-process volumes
Procedural Content (PCG) — full graph authoring plus six high-level scene macros: realistic forests (with clearings, density variation, edge falloff, undergrowth), rocky terrain, urban grid scatter, spline-following placement, and Nanite-skinned skeletal-mesh tree forests
Animation — Animation Blueprints, state machines, blend spaces, Sequencer cinematics
AI / Gameplay — Behavior Trees, EQS queries, AI Perception, GameplayAbilities
Audio & VFX — Niagara emitters, MetaSounds, sound classes/cues
3D Generation — Tripo AI integration for text/image-to-mesh
Game framework — GameMode, PlayerController, HUD, Pawn, Enhanced Input
Testing & QA — PIE control, screenshots, automated assert chains, deterministic test runners
…and a lot more. 480+ tools across 47 topic areas, all browsable via the in-editor rekall_guide reference.
Why native MCP
Most AI integrations are Python wrappers around Blueprint Library calls or external bridges that pipe JSON over RPC. They drift from engine semantics, miss editor-only APIs, and break with engine updates. Rekall is built differently:
In-process — runs on the UE editor thread, can call any UE editor API directly
Game-thread-safe — every tool wraps UObject access in a game-thread dispatch helper; no editor crashes from off-thread access
Discoverable — rekall_guide topic="<area>" returns long-form, hand-written workflow documentation that AI agents read before acting
agent_hint convention — every tool result includes natural-language guidance for the next step, surfacing pitfalls and recovery paths
Try this prompt
▎ "Create a landscape and place a realistic forest on it — trees clustered in natural patches
▎ with a couple of clearings, density fading at the edges, and saplings as undergrowth. Use the
▎ high-quality Procedural Vegetation Editor trees if you can. Then take a screenshot from a
▎ low angle so I can see them."
That single sentence resolves to a full pipeline: landscape creation → PCG forest with clearings/density-noise/edge-falloff/undergrowth → PCGVolume placement → camera positioning →screenshot. One sentence in, fully-realized scene out.
Works with
Any MCP-compatible AI client. Tested with:
- Claude Code (Anthropic)
- Cursor
- Windsurf
Getting started
1. Install from FAB
2. Enable "Rekall" in your project's plugin settings
3. Launch the editor — server starts automatically on 127.0.0.1:30080
4. Add Rekall to your AI client's MCP config (one-line JSON, see above)
5. Ask your AI agent to build something. Watch it happen.
Requirements
- Unreal Engine 5.7
- Windows 64-bit (primary tested platform)
- Editor-only plugin — Rekall is the authoring tool. Your final game ships as a normal UE project without Rekall; nothing in your shipped game depends on it.
A note on AI plugins
This isn't an AI runtime plugin (it doesn't put NPCs in your shipping game). It's an AI authoring plugin — it lets your AI assistant actually build the game, while you focus on the parts that need taste and judgment.
Required Engine Plugins
Rekall's tool groups are guarded by preprocessor defines — enable only what your project uses. Building from source requires: Interchange, EnhancedInput, Niagara, PCG, StateTree, GameplayAbilities, IKRig, PoseSearch, GeometryScripting, GeometryCollectionPlugin, Fracture, Metasound