Install, connect, automate.

1 / Install

Baiqi MCP Kit is a Win64 Unreal Editor plugin. The release ships the full C++ source for UE 5.5–5.8. Install it through Fab, or place the BaiqiMCPKit folder under your project's Plugins/ directory, then enable it in the editor.

Keep the plugin under Plugins/BaiqiMCPKit. The module is compiled on first load; a source checkout must be built with the engine version you launch. The plugin enables 11 built-in engine plugins (EditorScriptingUtilities, EnhancedInput, Niagara, PCG, PythonScriptPlugin, ControlRig, GameplayAbilities, Metasound, GeometryScripting, Fracture, SmartObjects) — they ship with Unreal Engine and each powers a tool domain.

2 / Connect an agent

The endpoint is a Streamable HTTP MCP server (JSON-RPC 2.0, MCP spec 2025-06-18). Point your client at:

Call initialize first and keep the Mcp-Session-Id response header — every later request must send it back. The transport is loopback-only by default.

Each tool call is one HTTP request, and the editor services requests on its render tick. When a task loops over many assets, use a batch form where one exists (get_static_mesh_info takes mesh_paths), and otherwise run the loop inside execute_python as a single call: a hundred separate requests cost a hundred round trips.

Reuse the HTTP connection. A fresh TCP connection per call costs seconds (measured around 2 s versus 0.7 s on a reused keep-alive connection, even for ping); a client that keeps one connection open is roughly three times faster. Standard MCP clients do this already — a hand-rolled one should reuse its HTTP session instead of opening a socket per request.

3 / What is inside

What it can do that a text-only agent cannot

• Nine-frame PIE previews. take_pie_screenshots schedules captures on the PIE world timer (interval_time defaults to 0.5 s), writes <base>_NN.png, tiles them into <base>_grid.png (3×3 for nine) and reports the pixel difference between consecutive frames.
• Animation assets, not only animation data. create_animation_sequence, create_montage, create_blend_space, create_aim_offset, create_pose_asset and create_anim_blueprint, plus montage sections, slots and notifies and anim-graph states and transitions — compiled and read back afterwards.
• Previews as files. render_mesh_preview, render_animation_pose, render_niagara_preview, render_umg_snapshot, render_blueprint_snapshot, take_editor_screenshot and take_pie_screenshots all write PNGs the agent can open; captures can also return base64.
• Input, not teleport. pie_inject_input holds movement and look through Enhanced Input (action_path), legacy axis keys (axis_name + mode=keys) or mode=direct; turn is a mouse delta spread over turn_frames, so the pawn actually walks. Pair it with take_pie_screenshots to see the motion.
• A closed loop. Write, read the value back, compile, capture, fix. Writes report what changed, validation returns every message, and destructive tools can require an editor-side approval before they run.

4 / Compatibility

Every stable tool registers on all four engine lanes with the same name and arguments. Where a capability depends on a newer engine API, the older lane registers a stub that returns a clear "requires UE 5.8" error instead of failing silently.

• Platform: Win64 (Editor).
• Engines: UE 5.5, 5.6, 5.7, 5.8.
• No external services — the server runs inside the editor process.

5 / Security

• Loopback-only by default; remote access is opt-in.
• Optional capability token for authenticated requests.
• Protected rails for read-only vs. destructive tools, plus an optional editor-side approval prompt.

6 / Need help?

Common issues and the details we need for a bug report are on the support page.