Build Games in Devin Desktop with Summer Engine MCP

Summer Engine in Devin Desktop

Devin Desktop (formerly Windsurf) is an AI-powered IDE that supports MCP (Model Context Protocol). With Summer Engine’s integration, Devin Local (formerly Cascade) — Devin Desktop’s agent panel — can control your game engine: add nodes to scenes, set properties, import assets, run the game, and debug, all from within your coding workflow. This guide covers the configuration. Setup takes about a minute.

Prerequisites

Devin Desktop: The Cognition-powered IDE (formerly Windsurf)
Node.js 22+: For running the MCP server
Summer Engine: Open with your project, for engine work only
Sign in once: npx -y summer-engine@latest login. One browser sign-in also connects the store, publishing and Grow tools

Configuration

Devin Desktop reads MCP servers from ~/.config/devin/mcp_config.json (or $XDG_CONFIG_HOME/devin/mcp_config.json; on Windows %APPDATA%\devin\mcp_config.json). The file uses the same mcpServers format as Cursor. There is no project-level file. Older Windsurf versions read ~/.codeium/windsurf/mcp_config.json.

Devin’s docs say mcp_config.json configures the Cascade agent. For the Devin agent, add the same command in the app’s MCP settings.

Step 1: Create or Edit the Config File

Create ~/.config/devin/mcp_config.json. If the file already exists (for example, for other MCP servers), add Summer Engine to the existing mcpServers object.

Step 2: Add Summer Engine

Use the one-line setup command:

npx -y summer-engine@latest setup windsurf --yes

setup devin works as an alias and produces the same result. Or add the config manually:

{
  "mcpServers": {
    "summer-engine": {
      "command": "npx",
      "args": ["-y", "summer-engine@latest", "mcp"]
    }
  }
}

{
  "mcpServers": {
    "other-server": { ... },
    "summer-engine": {
      "command": "npx",
      "args": ["-y", "summer-engine@latest", "mcp"]
    }
  }
}

Step 3: Restart Devin Desktop

Close and reopen Devin Desktop so it loads the new MCP config. The Summer Engine MCP server starts when Devin Desktop starts; it connects to the engine on the first tool call.

Step 4: Verify

Check Devin Desktop’s MCP or AI settings to confirm “summer-engine” appears and its tools are listed. Then try a prompt:

“Use Summer Engine to add a MeshInstance3D with a BoxMesh to the scene”

If the node appears in Summer Engine, the setup is working.

Cloud work only: connect by URL

For assets, plans, the store, publishing and Grow, with nothing to install, add the hosted Summer server under mcpServers in ~/.config/devin/mcp_config.json (Windows %APPDATA%\devin\mcp_config.json), then sign in when Devin Desktop asks:

{
  "mcpServers": {
    "summer-cloud": {
      "serverUrl": "https://mcp.summerengine.com/mcp"
    }
  }
}

Engine tools (scenes, scripts, play, screenshots) need the local server above. After summer login, the local server also runs the cloud tools, so use one of the two.

Using Summer Engine with Devin Desktop

Once configured, Devin Local can use Summer Engine’s tools when you ask for game-related changes. Example prompts:

“Add a Camera3D and DirectionalLight3D to the scene root”
“Get the scene tree from Summer Engine”
“Import this model and add it to the World node: [URL]”
“Run the game and capture a screenshot”
“Set the project’s main scene to res://main.tscn”

Engine tools need the engine. Open your project in Summer Engine first, or run npx summer-engine run from the project directory. Asset, plan, store and publishing tools do not need it.

Troubleshooting

”Summer Engine is not running” (`engine_not_running`)

Start Summer Engine and open your project. The MCP server connects to the engine’s local API on port 6550. The engine writes a token to ~/.summer/api-token when it starts. Every Summer error names its code and one next step (next). not_signed_in: run npx -y summer-engine@latest login. no_credits: add credits at https://www.summerengine.com/studio/credits. All codes: How Summer answers.

MCP server not appearing

Config path: Verify you’re using the config file Devin Desktop actually reads. Check the app’s MCP settings or documentation.
JSON validity: Ensure no trailing commas, proper quotes, and valid JSON structure
Restart: Fully quit and reopen Devin Desktop

Tools return errors

See Value formats for parameter formats. Common issues: wrong node path format (./World/Player), invalid property values (use engine string format like "Vector3(0, 10, 0)"), or the game running when scene edits are attempted (stop it first with summer_stop).

Next Steps

Operations reference

Every operation with its inputs and an example

Building a Game

How an AI builds a full game using MCP

MCP Setup Overview

Architecture, prerequisites, and other IDEs

CLI Reference

summer install, run, create, and more

Need help? Ask in Discord first. That is where you get the fastest reply and support. For concrete help, email support@summerengine.com or founders@summerengine.com.

​Summer Engine in Devin Desktop

​Prerequisites

​Configuration

​Step 1: Create or Edit the Config File

​Step 2: Add Summer Engine

​Step 3: Restart Devin Desktop

​Step 4: Verify

​Cloud work only: connect by URL

​Using Summer Engine with Devin Desktop

​Troubleshooting

​”Summer Engine is not running” (engine_not_running)

​MCP server not appearing

​Tools return errors

​Next Steps

Operations reference

Building a Game

MCP Setup Overview

CLI Reference

Summer Engine in Devin Desktop

Prerequisites

Configuration

Step 1: Create or Edit the Config File

Step 2: Add Summer Engine

Step 3: Restart Devin Desktop

Step 4: Verify

Cloud work only: connect by URL

Using Summer Engine with Devin Desktop

Troubleshooting

”Summer Engine is not running” (`engine_not_running`)

MCP server not appearing

Tools return errors

Next Steps