Hayba

The agentic engine for spatial and procedural world-building in Unreal Engine 5.

Hayba lets your AI agent (Claude / GPT / any MCP host) author UE5 scenes directly: spawn actors, build PCG graphs, validate physics, author materials, run sandboxed Python, and more — over a single MCP connection. Spatial-first: where every other MCP server treats UE as a 2D code repository, Hayba ships a PCG SQLite registry, a native 2D Slate cognitive map, and a visual grounding sidecar.

This repo is the UE5 MCP toolkit: the Node MCP server, the UE5 C++ editor plugin, the Python visual sidecar, and the public website.

Features

• 100+ tools across 30+ domains — Actor / Level / Scene / Asset / Blueprint / Material / Foliage / Spline / World Partition / ISM / Physics / Python / Editor / Docs / PCG / Sequencer / Animation / Niagara / Audio / MetaSound / GAS / Behavior Tree / Input / UI / Net / Mesh / Texture / Data / Project / Build / Test / Memory / Plan / Conventions

• PCG SQLite registry — 344 PCGEx nodes / 356 pins / 2270 properties scraped from C++ headers, queryable with semantic + structural intent

• Cognitive Map — 2D top-down semantic clustering of every actor in the level, force-directed mindmap renderer

• Visual sidecar — FastAPI + CLIP / SpatialCLIP / OWL-ViT for deep physics validation and spatial grounding, plus SAM segmentation for AI mask generation

• PLUMB constraint system — a closed primitive set + Semantic Studio for authoring physical-asset profiles, masks, and quantified placement constraints, evaluated as a directional Verdict pre-commit

• Plan Mode + native transactions — every destructive AI op wrapped in GEditor->BeginTransaction so Ctrl+Z just works

• Code Mode meta-tools — 3 tools (list_tool_categories / get_tool_signature / python_run) reduce initial payload by 92%, full catalog discovered on demand

• Multi-instance safe — dynamic port allocation (52342-52350) + heartbeat registry so multiple UE instances coexist

Related MCP server: soft-ue-cli

Repository layout

Quick start

1. Install the UE plugin

Copy unreal/HaybaMCPToolkit/ into your UE project's Plugins/ folder, regenerate Visual Studio project files, recompile (UE 5.7+, VS 2022).

2. Register the MCP server with your agent host

# Claude Code
claude mcp add hayba-toolkit -- node /path/to/hayba/mcp-tools/hayba-mcp/dist/index.js

// Claude Desktop — claude_desktop_config.json
{
  "mcpServers": {
    "hayba-toolkit": {
      "command": "node",
      "args": ["/path/to/hayba/mcp-tools/hayba-mcp/dist/index.js"]
    }
  }
}

3. Run the editor

Open UE; the Hayba MCP Toolkit panel appears in the toolbar. Pick Integrated (your MCP host drives the agent) or API Key (in-editor chat drives Anthropic/OpenAI directly).

Then ask Claude: "Search the PCG node catalog for voronoi, propose a 3-step plan to author a Voronoi graph, and execute it after I approve."

Architecture

┌──────────────────┐  stdio  ┌──────────────────┐  TCP   ┌────────────────┐
│  Agent Host      │ ◄────►  │  Node MCP Server │ ◄────► │  UE5 Plugin    │
│  (Claude / GPT)  │         │  mcp-tools/      │ :52342 │  unreal/       │
└──────────────────┘         │  hayba-mcp       │        │  HaybaMCP...   │
                             │  Zod · PCGEx DB  │        │  handlers      │
                             └──────────────────┘        └────────────────┘

Two language boundaries, one protocol. The TCP envelope on :52342 (auto-fallback :52343-52350) carries length-prefixed JSON. Plan Mode + the editor transaction system gate every destructive op. See docs/ARCHITECTURE.md and CONTEXT.md.

Documentation

• CONTEXT.md — domain glossary + repo philosophy (read this first)

• Architecture — language boundaries, the TCP seam, data flows

• Getting started — local dev setup and first run

• Wiki — guides, tool reference, troubleshooting

• ADRs — architectural decision records

• Contributing · Changelog · Security · Code of Conduct

Development

npm install                                   # all workspaces (Node ≥ 22.5 — see .nvmrc)
npm --prefix mcp-tools/hayba-mcp test         # the authoritative gate (tsc + vitest)

Run the gate locally before pushing.

License

Hayba's source code is MIT-licensed (see LICENSE).