godot-mcp-runtime

Godot MCP Runtime

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A lightweight MCP server that pairs comprehensive headless editing with full runtime control over a Godot 4.x project. Scene, node, autoload, and validation ops cover everything short of the most niche corners of the engine; the runtime bridge adds screenshots, input simulation, UI discovery, and live GDScript against the running scene tree.

<p align="center"><img src="docs/assets/demo.gif" alt="Agent driving a Godot game via MCP runtime tools" width="1000"></p>

<h3 align="center">The AI doesn't just write your game, it can check its work.</h3> <br>

• Headless editing — scenes, nodes, scripts, signals, validation, no editor window
• Runtime control — screenshots, input simulation, UI discovery, and live GDScript against the running game
• Zero footprint — no Godot addon, no project commits, auto-cleanup on shutdown

No addon required. Most Godot MCP servers that offer runtime support ship as a Godot addon, something you install into your project, commit to version control, and manage as a dependency. Use npx and there's no install or setup needed.

Think of it as Playwright MCP, but for Godot. This does the same thing for games: run the project, take a screenshot, simulate input, read what's on screen, execute a script against the live scene tree. The agent closes the loop on its own changes rather than handing off to you to verify.

[!NOTE] This is not a playtesting replacement. It doesn't catch the subtle feel issues that only a human notices, and it won't tell you if your game is fun. What it does is let an agent confirm that a scene loads, a button responds, a value updated, a script ran without errors. The ability to check work is crucial for AI driven workflows.

Contents

• What It Does
• How It Compares
• Quick Start
• Docs
• Acknowledgments
• License

What It Does

Built for agents. Every tool is purpose-built and self-documenting. When something fails, the response tells the agent how to fix it; when something succeeds, it points toward the next step. The result is an AI that stays unstuck and self-corrects without needing you to nudge it along.

Headless editing. Create scenes, add nodes, set properties, attach scripts, connect signals, validate GDScript. All the standard operations, no editor window required.

Runtime bridge. When run_project or attach_project is called, the server injects McpBridge as an autoload. This opens a localhost-only TCP listener (both auto-select a free port when bridgePort is omitted; pass bridgePort to pin a specific port) and enables:

• Screenshots: Capture the viewport — by default returns a 960x540 preview inline plus the full PNG on disk; use responseMode: 'full' for pixel-perfect or 'path_only' to skip the inline image
• Input simulation: Batched sequences of key presses, mouse clicks, mouse motion, UI element clicks by name or path, Godot action events, and timed waits
• UI discovery: Walk the live scene tree and collect every visible Control node with its position, type, text content, and disabled state
• Live script execution: Compile and run arbitrary GDScript with full SceneTree access while the game is running

Background mode. Pass background: true to run_project and the Godot window moves off-screen (positioned at (-9999, -9999)) with physical input blocked: borderless, unfocusable, mouse-passthrough. Programmatic input, screenshots, and all runtime tools work exactly the same. Useful for automated agent-driven testing where the window shouldn't be visible or interactive.

Manual attach mode. When something other than MCP launches the game (a CI pipeline, an external debugger, your own shell), call attach_project first. It injects the bridge and marks the project active without spawning Godot, so when you launch the game manually, runtime tools work against it. Use detach_project when done.

[!IMPORTANT] get_debug_output is unavailable in attached mode. stdout and stderr only flow through processes MCP started itself, so when Godot is launched externally there's no captured output to return. Use run_project if you need the debug stream.

The bridge cleans itself up automatically when stop_project or detach_project is called. No leftover autoloads, no modified project files.

How It Compares

The Godot MCP space splits on two axes: whether a server can drive a _running_ game (runtime) or only edit files, and what it costs your project to do so. Most servers that offer real runtime control ship as a Godot addon you install and commit to version control, or as a custom engine you download. This one injects a bridge transiently and removes it on shutdown, so you get full live-game control against stock Godot with nothing left in your repo.

| Server | Live-game runtime | Footprint | License | Price | | ------------------------- | ---------------------------------------------------------- | ------------------------------------ | ------------------------------ | --------------------- | | Godot MCP Runtime | Full: screenshots, input, live scene tree, script exec | Zero (npx, no committed addon) | MIT | Free | | Summer Engine | Full | Custom engine download + sign-in | MIT layer / proprietary engine | Free core, paid cloud | | tugcantopaloglu/godot-mcp | Full | Committed autoload addon | MIT | Free | | Godot MCP Pro | Full | Committed editor addon | Proprietary | $15 | | GDAI MCP | Editor-mediated | Committed editor addon | Proprietary | $19 | | Coding-Solo/godot-mcp | No (launch + debug output) | Zero (npx) | MIT | Free |

Among servers with full live-game control, Godot MCP Runtime pairs a zero-footprint install (no addon committed to version control, no custom engine, no account) with a single npx command, and it has shipped this transient-autoload runtime bridge since February 2026. One other project, Vollkorn-Games/godot-mcp, independently arrived at the same design at the same time and is the only other server in this niche; it's earlier-stage and installs from source rather than npm. For the full field of ~20 servers with a source for every claim, see docs/comparison.md.

Quick Start

Prerequisites

• Node.js v20+
• Godot 4.x

That's it. No Godot addon, no project modifications.

Configure Your MCP Client

Add the following to your MCP client config. Works with Claude Code, Claude Desktop, Cursor, or any MCP-compatible client.

Zero-install via npx (recommended):

{
  "mcpServers": {
    "godot": {
      "command": "npx",
      "args": ["-y", "godot-mcp-runtime"],
      "env": {
        "GODOT_PATH": "<path-to-godot-executable>"
      }
    }
  }
}

Or install globally:

npm install -g godot-mcp-runtime

{
  "mcpServers": {
    "godot": {
      "command": "godot-mcp-runtime",
      "env": {
        "GODOT_PATH": "<path-to-godot-executable>"
      }
    }
  }
}

Or clone from source:

git clone https://github.com/Erodenn/godot-mcp-runtime.git
cd godot-mcp-runtime
npm install
npm run build

{
  "mcpServers": {
    "godot": {
      "command": "node",
      "args": ["<path-to>/godot-mcp-runtime/dist/index.js"],
      "env": {
        "GODOT_PATH": "<path-to-godot-executable>"
      }
    }
  }
}

[!TIP] Prefer pnpm? All three install paths work with pnpm. Substitute pnpm dlx godot-mcp-runtime for npx -y godot-mcp-runtime, pnpm add -g godot-mcp-runtime for the global install, or pnpm install && pnpm run build for the source build. pnpm ships stronger defaults against npm supply-chain attacks; see pnpm's supply chain security guide.

If Godot is on your PATH, you can omit GODOT_PATH entirely. The server will auto-detect it.

Optional environment variables

All are set in the same env block as GODOT_PATH:

| Variable | Effect | | ------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | DEBUG | "true" enables verbose [DEBUG] logging. | | GODOT_MCP_DISABLE_ELICITATION | "true" disables the confirmation prompts for run_project and run_script. Use this if your client cannot display elicitation prompts (e.g. Claude Desktop, which auto-cancels them). Fail-open: the action proceeds with a warning. Tier 1 security hard-blocks still apply. | | GODOT_MCP_STRICT | "true" hard-rejects anything that would otherwise prompt, for unattended operation. Takes precedence over GODOT_MCP_DISABLE_ELICITATION when both are set. |

{
  "mcpServers": {
    "godot": {
      "command": "npx",
      "args": ["-y", "godot-mcp-runtime"],
      "env": {
        "GODOT_PATH": "<path-to-godot-executable>",
        "GODOT_MCP_DISABLE_ELICITATION": "true"
      }
    }
  }
}

[!IMPORTANT] Windows path gotchas. GODOT_PATH must point at the Godot executable itself, not its install folder. Backslashes in JSON must be escaped or replaced with forward slashes: ``json "GODOT_PATH": "D:\\Godot\\Godot_v4.4-stable_win64.exe" // or equivalently "GODOT_PATH": "D:/Godot/Godot_v4.4-stable_win64.exe" ` Setting the variable from a wrapper .bat does not propagate to the MCP server — the path must live in the client's env` block above.

Verify

Ask your AI assistant to call get_project_info. If it returns a Godot version string (e.g., 4.4.stable), you're connected and working.

Security model

run_script and run_project execute arbitrary GDScript inside the live Godot process, which runs with full user privileges. The server defends against this with a three-tier static-analysis gate that inspects GDScript before forwarding it to the bridge:

• Tier 1 (hard block) — direct exec (OS.execute/shell_open/…), reflection bypasses (ClassDB.instantiate, Object.set_script), dynamic code (Expression, str_to_var), and non-literal load/preload/call are rejected server-side.
• Tier 2 (elicit) — filesystem writes (FileAccess.open, DirAccess.remove) and network primitives (HTTPRequest, TCPServer, …) trigger a user-confirmation prompt via MCP elicitation.
• Tier 3 (warn) — literal load("res://…") and similar common idioms execute, but findings surface in the response warnings array.

run_project runs the same scan over [autoload] scripts and scripts attached to the launched scene before spawning Godot.

Set GODOT_MCP_STRICT=true to promote every Tier 2 finding to a hard block — needed for unattended operation where MCP client bypass-permissions modes auto-accept elicitation. Off by default.

Set GODOT_MCP_DISABLE_ELICITATION=true for clients that cannot display elicitation prompts (e.g. Claude Desktop, which auto-cancels them). It skips the confirmation prompts and proceeds (fail-open): run_project launches and Tier 2 run_script findings run with a warning. Tier 1 hard blocks are unaffected. Strict mode takes precedence when both are set. Off by default.

Every run_script call writes a .policy.json sidecar next to the audit-trail .gd file in .mcp/scripts/. See docs/security.md for the full rule catalogue.

Docs

• docs/tools.md — full tool reference, grouped by category
• docs/tool-authoring.md — standards for adding or modifying tools
• docs/architecture.md — source layout, bridge sequence diagram, lifecycle steps, runtime artifact behavior
• docs/security.md — run_script / run_project security model, full rule catalogue, strict-mode behavior

Acknowledgments

Built on the foundation laid by Coding-Solo/godot-mcp for headless Godot operations.

Developed with Claude Code.

License

MIT