What is the Summer CLI?

The Summer CLI is the terminal command (run via npx summer-engine) that installs Summer Engine, signs you in, scaffolds and runs game projects, and connects your AI coding agent to the running engine through MCP. It is the fastest way to go from nothing to a playable game.

How do I install the Summer CLI?

You do not have to install it globally. Paste the setup prompt into Claude Code, Cursor, Codex, or any AI agent and it runs the CLI for you via npx. To use it yourself, run npx -y summer-engine@latest doctor. npx downloads the small package on first use and caches it.

Is the Summer CLI free and open source?

Yes. The Summer CLI, the MCP server, the game-dev skills, and the plugin manifests are MIT open source on GitHub. The Summer Engine desktop app is free to download. Only hosted AI and cloud asset generation are usage-based.

Which AI agents does the Summer CLI work with?

Claude Code, Cursor, Codex CLI, Windsurf, Cline, Roo Code, Gemini CLI, GitHub Copilot CLI, GitHub Copilot in VS Code, and OpenCode. Run summer setup and the CLI writes the right config for each one.

What is the difference between the Summer CLI and the Summer MCP server?

The CLI installs and manages Summer (download, login, scaffold, run, doctor). The MCP server is what the CLI starts so your agent can operate the running engine: create scenes, set properties, run the game, and read errors. You get both from the same package.

Yes, Node.js 18 or newer, because the CLI ships as an npm package run through npx. If node --version does not print 18+, install it from nodejs.org and re-run the setup prompt.

Summer CLI

Make games fromyour terminal.

The Summer CLI installs Summer Engine, signs you in, scaffolds a project, and connects Claude Code, Cursor, Codex, and other AI agents to a real desktop game engine. One paste to start.

or run the CLI directly

MIT open sourceFree to useWorks with every major AI agent

Download desktop app Summer MCP setup View on GitHub

How it works

One paste. The agent does the rest.

Paste the prompt

Drop the setup prompt into Claude Code, Cursor, Codex, or any AI agent. No slash commands, no manual installs.

The CLI installs what's missing

The agent reads the repo, runs the Summer CLI, downloads the engine, installs the game-dev skills, and logs you in.

Build in a real engine

Your agent gets 44 MCP tools to create scenes, run the game, fix errors, and export to Steam, desktop, and mobile.

CLI reference

What the Summer CLI can do.

Run any command through npx -y summer-engine@latest — no global install required.

summer installDownload the Summer Engine desktop app. Prints the URL and size first.

summer loginBrowser-based sign-in. The token is shared with the engine.

summer create <template> [name]Scaffold a new game project from a template.

summer run [path]Launch the engine with your project loaded.

summer setup <agent>One shot: write the MCP config, install the game-dev skills, run doctor.

summer doctorDiagnose Node, login, engine, project memory, and the MCP connection.

summer mcpStart the MCP server that gives your agent 44 engine tools.

Summer CLI

Installs and manages Summer.

Downloads the engine and signs you in
Scaffolds and runs projects
Writes agent config and installs skills
Diagnoses your setup with summer doctor

Summer MCP

Lets your agent drive the engine.

The CLI starts the Summer MCP server so your AI agent gets 44 tools to operate the running engine: create scenes, set properties, run the game, inspect errors, and import or generate assets.

Explore Summer MCP

FAQ

Summer CLI questions.

What is the Summer CLI?: The Summer CLI is the terminal command (run via npx summer-engine) that installs Summer Engine, signs you in, scaffolds and runs game projects, and connects your AI coding agent to the running engine through MCP. It is the fastest way to go from nothing to a playable game.
How do I install the Summer CLI?: You do not have to install it globally. Paste the setup prompt into Claude Code, Cursor, Codex, or any AI agent and it runs the CLI for you via npx. To use it yourself, run npx -y summer-engine@latest doctor. npx downloads the small package on first use and caches it.
Is the Summer CLI free and open source?: Yes. The Summer CLI, the MCP server, the game-dev skills, and the plugin manifests are MIT open source on GitHub. The Summer Engine desktop app is free to download. Only hosted AI and cloud asset generation are usage-based.
Which AI agents does the Summer CLI work with?: Claude Code, Cursor, Codex CLI, Windsurf, Cline, Roo Code, Gemini CLI, GitHub Copilot CLI, GitHub Copilot in VS Code, and OpenCode. Run summer setup <agent> and the CLI writes the right config for each one.
What is the difference between the Summer CLI and the Summer MCP server?: The CLI installs and manages Summer (download, login, scaffold, run, doctor). The MCP server is what the CLI starts so your agent can operate the running engine: create scenes, set properties, run the game, and read errors. You get both from the same package.
Do I need Node.js?: Yes, Node.js 18 or newer, because the CLI ships as an npm package run through npx. If node --version does not print 18+, install it from nodejs.org and re-run the setup prompt.

Install Summer Engine and make a game.

Paste the setup prompt into your AI agent, or run the CLI yourself. Free, MIT, one command to start.

Download desktop app Read the docs