Engine-agnostic Model Context Protocol server shared by the game-engine MCP plugins:

Unity-MCP — Unity Editor & games
Godot-MCP — Godot Editor & games
Unreal-MCP — Unreal Editor & games

It is a thin host over the NuGet packages com.IvanMurzak.McpPlugin.Server and com.IvanMurzak.ReflectorNet, where all the real server logic lives. The server bridges MCP clients (Claude, Cursor, Copilot, …) and an engine plugin over SignalR:

MCP client  ⇄  gamedev-mcp-server  ⇄ (SignalR) ⇄  engine plugin (Unity / Godot / Unreal)

There is no engine-specific code in this repository — one server binary serves all three engine plugins. Tools, resources and prompts are provided dynamically by whichever engine plugin connects.

Not to be confused with AI-Game-Dev-Server — the cloud LLM/billing proxy. This project is the local MCP stdio/http proxy host.

Install / Run

Pre-built executables

Download the zip for your platform from Releases (gamedev-mcp-server-<rid>.zip — win-x64, win-x86, win-arm64, linux-x64, linux-arm64, osx-x64, osx-arm64), unzip, and run:

./gamedev-mcp-server --port 8080 --client-transport stdio

Typical MCP client configuration (stdio):

{
  "mcpServers": {
    "GameDev-MCP": {
      "command": "path/to/gamedev-mcp-server",
      "args": ["--port=8080", "--client-transport=stdio"]
    }
  }
}

Docker

docker run -i --rm -p 8080:8080 aigamedeveloper/mcp-server

dotnet tool

dotnet tool install --global com.IvanMurzak.GameDev.MCP.Server
gamedev-mcp-server --port 8080

Build from source

dotnet build com.IvanMurzak.GameDev.MCP.Server.csproj
dotnet run --project com.IvanMurzak.GameDev.MCP.Server.csproj -- --client-transport stdio --port 8080

Cross-platform self-contained executables for all 7 RIDs: ./build/build-all.sh (bash) or ./build/build-all.ps1 (PowerShell). Outputs land in publish/<rid>/ and are zipped as gamedev-mcp-server-<rid>.zip (skip zipping with --no-zip / -NoZip).

Configuration

CLI arguments override environment variables.

Environment variable	CLI argument	Default	Description
`MCP_PLUGIN_PORT`	`--port`	`8080`	Client → Server ← Plugin connection port
`MCP_PLUGIN_CLIENT_TIMEOUT`	`--plugin-timeout`	`10000`	Plugin → Server connection timeout (ms)
`MCP_PLUGIN_CLIENT_TRANSPORT`	`--client-transport`	`stdio`	Client → Server transport: `stdio` or `streamableHttp`
`MCP_PLUGIN_IDLE_TIMEOUT_SECONDS`	`--idle-timeout-seconds`	`21600`	streamableHttp idle-session eviction window (this host seeds 6h instead of the package default of 600s)
`MCP_AUTH`	`--auth`	transport-dependent (see Authentication)	Authentication mode: `none` or `oauth`
`MCP_AUTH_ISSUER`	`--auth-issuer`	—	OAuth authorization-server URL (e.g. `https://ai-game.dev`). Required for `oauth`
`MCP_PUBLIC_URL`	`--public-url`	—	This server's canonical public URL / token audience (e.g. `https://ai-game.dev/mcp`). Required for `oauth`; seeds the Origin allow-list
`MCP_BIND`	`--bind`	`loopback`	Bind address: `loopback`, `any` (0.0.0.0), or a specific IP. Hosted deploys behind a proxy set `any`/`0.0.0.0`
`MCP_ALLOWED_ORIGINS`	`--allowed-origins`	—	Comma/semicolon-separated additional allowed browser Origins (added to loopback + the `--public-url` origin)

Logs are written to logs/server-log.txt (and logs/server-log-error.txt); in stdio mode console logging is redirected to stderr so stdout stays clean for the MCP JSON stream.

Authentication

The server is an OAuth 2.1 resource server. Two modes:

Mode	Auth	Default for	Use
`none`	none — single-instance, zero-config	stdio	offline / local dev / CI
`oauth`	ES256 JWT validated locally via cached JWKS (with PAT introspection fallback); `401` + `resource_metadata` challenge	streamableHttp	signed-in localhost and hosted

Transport-conditional default: stdio defaults to none. streamableHttp defaults to oauth when both --auth-issuer and --public-url are configured; otherwise it stays on none and logs a warning (so the zero-config docker run / --port 8080 quickstart still works). An explicit --auth always wins.
oauth requires --auth-issuer (the authorization server, e.g. https://ai-game.dev) and --public-url (this server's canonical audience). Startup fails fast if either is missing while --auth oauth is set.
Origin validation (DNS-rebinding defense) runs in all modes: a request with a non-allowed Origin gets 403. Loopback and the --public-url origin are allowed by default; add more with MCP_ALLOWED_ORIGINS.
Bind defaults to loopback. Set --bind any (or 0.0.0.0) for a hosted deployment a reverse proxy must reach.

# Local, offline (stdio, none) — unchanged zero-config default:
gamedev-mcp-server --client-transport stdio --port 8080

# Hosted resource server (streamableHttp, oauth), reachable by nginx:
gamedev-mcp-server --client-transport streamableHttp --port 8080 \
  --auth oauth --auth-issuer https://ai-game.dev --public-url https://ai-game.dev/mcp \
  --bind 0.0.0.0

Configure an AI agent

Write a project-scoped, pinned MCP client config for any supported AI agent from the terminal — no editor UI, no token copy/paste (native OAuth authorize):

# Local server, current project:
gamedev-mcp-server configure --agent claude-code
# Hosted server:
gamedev-mcp-server configure --agent codex --url https://ai-game.dev/mcp
# List agents:
gamedev-mcp-server configure --help

Each written config is URL-only (credentials are never written into project files) and carries the project pin (…/p/<pin> path segment) plus, for local servers, the deterministic per-project port — so agent sessions launched in this project folder route strictly to this project's engine. --agent <id> accepts any id from configure --help (e.g. claude-code, codex, cursor, vscode-copilot, …); --transport stdio writes a stdio spawn config instead of an HTTP one; --project <path> targets a different project root (default: current directory).

Compatibility

GameDev-MCP-Server	McpPlugin.Server	ReflectorNet	Engine plugins
8.0.3 (released)	6.11.0	5.3.1	engine plugins on McpPlugin 6.x
9.0.0 (released)	7.0.0-preview.1	5.3.2	engine plugins on McpPlugin 7.x (Phase 4)

Development snapshot. The released 9.0.0 server line builds against McpPlugin.Server 7.0.0-preview.1 (the mcp-authorize resource-server major). The main branch is now an in-development 9.1.0 snapshot building against McpPlugin.Server 7.1.1 — its <Version> / server.json version bump and the Docker/zip/dotnet-tool publish are a separate, owner-gated release step. Any 9.x server needs an engine plugin built on McpPlugin 7.x (the instance-metadata handshake + oauth mode); older McpPlugin 6.x plugins pair with the released 8.0.3 server line.

GameDev MCP Server

README