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Summer Engine in Zed

Zed is a fast, AI-powered code editor that supports MCP (Model Context Protocol) through its Agent Panel. With Summer Engine’s integration, Zed’s AI 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.

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Prerequisites

  • Zed: The high-performance editor with built-in AI
  • Node.js: For running the MCP server (Node 18+)
  • Summer Engine: Installed and running with your project open

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Configuration

Zed uses context_servers in its settings. You can add Summer Engine via:
  • Settings file: ~/.config/zed/settings.json (or $XDG_CONFIG_HOME/zed/settings.json on Linux)
  • Project-level: .zed/settings.json in your project root (create via zed: open project settings)
  • UI: Agent Panel → Settings → Add Custom Server

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Step 1: Open Settings

Press Cmd+, (Mac) or Ctrl+, (Linux/Windows), or run zed: open settings from the Command Palette. For project-specific config, run zed: open project settings to create .zed/settings.json.

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Step 2: Add Summer Engine

Add the context_servers entry. If it already exists, add summer-engine to the object: 
{
  "context_servers": {
    "summer-engine": {
      "command": "npx",
      "args": ["summer-engine", "mcp"],
      "env": {}
    }
  }
}

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Step 3: Restart Zed

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

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Step 4: Verify

  1. Open the Agent Panel (top-right menu or Command Palette)
  2. Go to Settings and check the context servers list
  3. A green dot next to summer-engine means it’s active
  4. 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.

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Using Summer Engine with Zed

Once configured, the AI 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 must be running. Zed’s AI talks to Summer Engine over localhost. Open your project in the engine first, or run npx summer-engine run from the project directory.

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Troubleshooting

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”Summer Engine is 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.

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MCP server not appearing or red dot

  • Config path: Verify settings are in ~/.config/zed/settings.json or .zed/settings.json in your project
  • JSON validity: Ensure no trailing commas, proper quotes, and valid JSON structure
  • Restart: Fully quit and reopen Zed

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Tools return errors

See the Tools Reference 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).

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Next Steps

Tools Reference

All 23 MCP tools with parameters and examples

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 or have questions? Reach out to our founders at founders@summerengine.com or join our community on Discord for fast responses.