Skip to main content

​
Overview

The Summer Engine CLI (summer) lets you install the engine, manage projects, sign in, and run the MCP server. Use it from the terminal or via npx summer-engine <command> without a global install. Install (one-time): 
npm install -g summer-engine
Or use without installing: 
npx summer-engine <command>

​
Commands

​
summer install

Download and install Summer Engine to your system. 
summer install [--path <dir>]
OptionDescription
--path <dir>Custom install directory (macOS: default is /Applications/Summer.app)
Platforms: macOS and Windows. Linux users are directed to download manually from summerengine.com. What it does: Fetches the latest release from Summer Engine’s API, downloads the installer (~145MB), and installs the app. On macOS it mounts the DMG and copies Summer.app to Applications. On Windows it runs the installer. Next steps after install: Run summer login to sign in, then summer run to launch.

​
summer login

Sign in to your Summer Engine account via browser OAuth. 
summer login [--force]
OptionDescription
--forceRe-authenticate even if already logged in
What it does: Opens your browser to the Summer Engine login page. After you sign in with Google, GitHub, or email, the CLI polls for the session and saves the token to ~/.summer/auth-token. Used for analytics and future cloud features. The MCP server uses a separate local token (~/.summer/api-token) for engine communication. You don’t need to be logged in for MCP to work, but login is recommended.

​
summer logout

Clear your saved auth tokens. 
summer logout
What it does: Removes ~/.summer/auth-token and user info. Does not affect the engine’s local API token. Run summer login again to re-authenticate.

​
summer status

Check engine status, API connection, and auth state. 
summer status
What it does: Reports:
  • Auth: Whether you’re logged in and with which email
  • Engine: Whether Summer Engine is running, which project is open, current scene
  • API: Port (default 6550) and token presence
Use this to debug “Summer Engine is not running” errors or verify your setup.

​
summer run

Launch Summer Engine, optionally opening a project. 
summer run [path]
ArgumentDescription
pathPath to a project directory (must contain project.godot). Optional.
What it does: Finds the Summer Engine binary (e.g., /Applications/Summer.app on macOS), spawns it with --editor, and optionally passes --path <projectPath>. Waits for the local API to respond (up to 20 seconds). If the engine is already running, it reports the current state and exits. Examples: 
summer run                    # Launch engine (no project)
summer run my-game            # Launch and open my-game/
summer run ./projects/racer   # Launch and open relative path

​
summer open

Open a project in Summer Engine. 
summer open <path>
ArgumentDescription
pathPath to project directory (must contain project.godot)
What it does: Resolves the path and checks for project.godot. If the engine is not running, it launches the engine with that project (same as summer run <path>). If the engine is already running, it prints the path and a note: to switch projects, close the current one in the engine first or run summer run <path>.

​
summer create

Create a new project from a template. 
summer create <template> [name]
ArgumentDescription
templateTemplate name: empty or 3d-basic
nameProject directory name (defaults to template name)
Templates:
TemplateDescription
emptyEmpty 3D project with a root Node3D
3d-basic3D scene with Camera3D, DirectionalLight3D, floor mesh, and sky
What it does: Creates a new directory, writes project.godot and a scene file. The project is ready to open with summer run <name>. Examples: 
summer create 3d-basic my-game    # Creates my-game/ with 3d-basic template
summer create empty                # Creates empty/ with empty template

​
summer list

List available templates or local projects. 
summer list <what>
ArgumentDescription
whattemplates or projects
What it does:
  • templates: Shows built-in templates (empty, 3d-basic) with short descriptions
  • projects: Scans the current directory for subdirectories containing project.godot and lists them
Examples: 
summer list templates   # See available templates
summer list projects   # See projects in current folder

​
summer mcp

Start the MCP server for AI tool integration. 
summer mcp
What it does: Starts the MCP server on stdio. This command is typically invoked by your IDE (Cursor, Claude Code, Windsurf) when they load the MCP config. You rarely run it manually. When run directly, it blocks and waits for JSON-RPC messages on stdin. Exposes 23 tools for scene manipulation, debugging, and project operations. Used by: Cursor, Claude Code, Windsurf, and other MCP-compatible tools. See MCP Setup for configuration.

​
summer skills

Install and manage best-practice guides for AI agents building games. Skills are markdown files that teach patterns for GDScript, scene composition, FPS controllers, lighting, and UI. 
summer skills list                    # List available skills
summer skills install <name>          # Install to ~/.summer/skills/
summer skills install --all           # Install all skills at once
summer skills install <name> --as-claude-skill   # Install to ~/.claude/skills/ for Claude Code
summer skills install <name> --as-cursor-skill   # Install to ~/.cursor/skills/ for Cursor
summer skills info <name>             # Show description and preview
OptionDescription
--allInstall all available skills
--as-claude-skillInstall to ~/.claude/skills/ so Claude Code auto-discovers the skill
--as-cursor-skillInstall to ~/.cursor/skills/ so Cursor auto-discovers the skill
Available skills:
SkillDescription
gdscript-patternsCommon GDScript idioms, signals, exports, type hints
scene-compositionScene structure, sub-scenes, node hierarchy
fps-controllerFirst-person character controller (movement, camera, physics)
3d-lightingLighting setup, environment, sky, shadows
ui-basicsHUD, menus, health bars, responsive layout
What it does: Copies the skill from the bundled package to ~/.summer/skills/<name>/. AI agents can read the SKILL.md file when building games. Skills follow the Agent Skills open standard. Examples: 
summer skills list
summer skills install fps-controller
summer skills install --all
summer skills install fps-controller --as-claude-skill   # For Claude Code
summer skills install fps-controller --as-cursor-skill   # For Cursor
summer skills info gdscript-patterns
See Skills for a full overview of the skills system.

​
Environment Variables

VariableDescription
SUMMER_GATEWAY_URLOverride the auth/gateway URL (default: https://www.summerengine.com). Used for local development.
SUMMER_SKILLS_DIROverride skills install directory (default: ~/.summer/skills/).

​
File Locations

PathPurpose
~/.summer/auth-tokenUser auth token (from summer login)
~/.summer/user.jsonCached user info (id, email, name)
~/.summer/api-tokenLocal engine API token (created by engine on startup)
~/.summer/api-portOverride port if default 6550 is occupied
~/.summer/skills/Installed skills (from summer skills install)
~/.claude/skills/Skills installed with --as-claude-skill (Claude Code auto-discovery)
~/.cursor/skills/Skills installed with --as-cursor-skill (Cursor auto-discovery)

​
Next Steps

Skills

Best-practice guides for AI agents

MCP Setup

Connect Cursor, Claude Code, or Windsurf

Tools Reference

All 23 MCP tools with parameters

Building a Game

Step-by-step guide for AI agents
Need help or have questions? Reach out to our founders at founders@summerengine.com or join our community on Discord for fast responses.