Summer Engine

Name: Summer Engine
Author: summerengine

by summerengineversion 4.5.0i★ –iComputer or cloud

Registry nameio.github.SummerEngine/summer

Install

Overview

Description from the maker (original English)

The game engine built for AI. Any agent makes a multiplayer game and publishes it.

PopNx MCP’s three pillars

These three are never merged into one score: opinions, measurements and popularity are different things.

User voiceiNo reviews yetReviews open together with accounts in a later step
Our basic checksi3 of 3 passedChecked from public information; code not scanned yet
UsageiNot measured yet★ –

What you can do with it

We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.

Connection: Computer or cloud
Transport: stdio, Streamable HTTP
Category: Games, sports, food & learning

Install

Pick the AI app you use, then copy the settings.

Before you install

Basic checks: 3 of 3 passed
Runs on the maker’s server: what you ask it goes through their server.
The registry lists no key to fill in.

You need

Runs in the cloudNothing to install; it connects over the internet
npmNode.js installed (for the npx command)

Which app do you use?

ClaudeClaude CodeCursorVS CodeChatGPT

Pick your app above. We remember it, so next time the button says “Install in …”.

Works in Claude on the web, desktop and mobile:

Open Settings → Connectors
Press Add custom connector
Paste the address below and press Add
If it asks you to sign in, sign in with the maker

https://mcp.summerengine.com/mcp

Or run it on your computer

Open Claude Desktop → Settings → Developer → Edit Config, and paste this into claude_desktop_config.json

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

Run this in your terminal

claude mcp add --transport http summer https://mcp.summerengine.com/mcp

Or run it on your computer

claude mcp add summer -- npx -y summer-engine mcp

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

{
  "mcpServers": {
    "summer": {
      "url": "https://mcp.summerengine.com/mcp"
    }
  }
}

Or run it on your computer

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

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

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "summer": {
      "type": "http",
      "url": "https://mcp.summerengine.com/mcp"
    }
  }
}

Or run it on your computer

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "summer": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "summer-engine",
        "mcp"
      ]
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

ChatGPT connects only to servers on the internet:

Open ChatGPT on the web → Settings → Connectors (Apps)
Press Create or Add (some plans need Developer mode under Advanced first)
Paste the address below, give it a name and save
If it asks you to sign in, sign in with the maker

https://mcp.summerengine.com/mcp

Menu names can differ slightly by plan and over time.

Your choice stays on this device in a cookie; no account needed.

These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

What it can do

The server asks you to sign in before it lists its tools.

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 7, 2026

✓ Pass
Maker matches the repo
The registry name was verified with the GitHub account summerengine, which owns the repo
… Not checked yet
Still maintained
We have not read this repo from GitHub yet
… Not checked yet
Has a licence
We have not read this repo from GitHub yet
✓ Pass
Endpoint responds
Responded in 403 ms (HTTP 401)
✓ Pass
Sign-in with OAuth
Declares OAuth sign-in, so your AI app can take you to log in
… Not checked yet
No hidden instructions in tool descriptions
Not checked yet; we read the tool list when we check the endpoint

Compared with others in Games, sports, food & learningi

More stars than 0% of the other 1283 servers in this category
Published to the registry more recently than 64% of the other 1283 servers in this category
Basic checks equal to or better than 100% of the other 1283 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Common questions

Is Summer Engine safe?

It passed 3 of 3 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.

What keys or codes does it need?

The registry does not list a required key, though some servers ask you to sign in on first use.

Does it run on my computer or in the cloud?

Either way works: install it on your computer or connect to the cloud version.

Is it still maintained?

The GitHub repo last changed –, and the latest version (4.5.0) reached the registry 18 days ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. It connects by URL, so apps that accept remote MCP servers work too, such as ChatGPT in developer mode.

What can I use instead?

In the same category: Neural Cosmology, slopped.site, Artsonia MCP

Alternatives

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Reading a card:★ GitHub starsiThree pillars: reviews · checks · usageiUpdated = latest version published to the registryi

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README from the maker

Open the README

Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.

Summer Engine: MCP server, CLI and skills

The game engine built for AI.

Any agent builds, tests and publishes a full multiplayer game. MCP server · game-dev skills · `summer` CLI, in one npm package: `summer-engine`.

Website · Docs · CLI setup · MCP setup

Install

Start a game now (Node 22+): npx -y summer-engine@latest dev. It asks before it installs the Summer Engine app (about 660 MB, free) when it is missing, creates a starter project here (in ./my-game when this folder has other files) and opens it, ready for your agent. No sign-in needed to build.
Chat apps (Claude, ChatGPT, Cursor...): add https://mcp.summerengine.com/mcp. Nothing to install.
Homebrew: brew install summerengine/tap/summer
npm (Node 22+): npm install -g summer-engine

CLI only (summer-engine 4.2.0 or newer), no MCP server: summer setup --cli. summer ops search "publish my game" finds any operation, signed in or not.

Connect

Cloud work: `https://mcp.summerengine.com/mcp`. Nothing to install. Add the URL to your agent and sign in to your Summer account once. Your agent then makes assets (images, 3D models, motion, sound effects, music, voices, video), searches and downloads your Summer asset library, plans games, and runs your projects, the store, publishing, prices, analytics, A/B tests, your team and Studio. It has no engine tools: for those, use the local server below.

Agent	Add the hosted server
Claude Code	`claude mcp add --transport http summer-cloud https://mcp.summerengine.com/mcp`, then `/mcp` to sign in
Codex	`codex mcp add summer-cloud --url https://mcp.summerengine.com/mcp`, then `codex mcp login summer-cloud`
Cursor	Add to Cursor, or add `"summer-cloud": {"url": "https://mcp.summerengine.com/mcp"}` under `mcpServers` in `~/.cursor/mcp.json`
VS Code	Add to VS Code, or `code --add-mcp '{"name":"summer-cloud","type":"http","url":"https://mcp.summerengine.com/mcp"}'`
Devin Desktop (formerly Windsurf)	add `"summer-cloud": {"serverUrl": "https://mcp.summerengine.com/mcp"}` under `mcpServers` in `~/.config/devin/mcp_config.json` (Windows `%APPDATA%\devin\mcp_config.json`)
Claude Desktop, claude.ai	Settings > Connectors > Add custom connector, then paste the URL

Engine work: `npx -y summer-engine@latest setup --yes` (needs Node 22+). It writes the local server (summer mcp) into your agent's config with the skills. The local server drives the Summer Engine app on your machine: build scenes, write scripts, play the game, take screenshots, read errors. After summer login it also runs every cloud operation, so your agent needs one server. Or paste the prompt in Get started and your agent does every step.

CLI only (summer-engine 4.2.0 or newer): `npx -y summer-engine@latest setup --cli --yes`. No MCP server: your agent runs Summer as commands in its shell. Setup installs the skills for your agent, with summer-cli, the guide to the commands, and writes no MCP entry. Your agent signs you in with summer login, finds an operation with summer ops search " " and runs it as summer -- , with --dry-run, --wait and --json. Engine commands (summer engine …) drive the Summer Engine app on your machine. Each skill ends with a table of the command for every tool it names. Add --assets-only for only the asset skills. --no-mcp is the same as --cli.

ChatGPT and Claude's connector directory use two reviewed store versions with a fixed tool list: https://mcp.summerengine.com/chatgpt (games, assets and generation; no publishing, no billing links) and https://mcp.summerengine.com/directory (the store, publishing and Grow reads; no image, 3D, audio or video generation). They keep their 3.x tool names and have no summer_search or summer_call. For everything else, use /mcp.

What this is

Summer Engine is the game engine built for AI. This repo connects your AI coding agent (Claude Code, Cursor, Codex, Copilot and many more) to it: the agent builds a whole game in the engine, tests it, publishes it to summer.games and reads how players play it.

Part	What it does
MCP server (`summer mcp`)	Tools your agent calls to drive the running editor: build scenes, write scripts, play the game, take screenshots, read errors. After `summer login` it also runs the cloud operations: assets, plans, the store, publishing, prices and analytics.
Skills	Game-dev know-how your agent loads: movement, combat, multiplayer, VFX, audio, UI, level design and more.
CLI (`summer`)	Installs the engine, signs you in, sets up your agent, creates projects from templates and publishes games.

This repo is not the engine itself. The CLI downloads the Summer Engine app for you.

With Summer installed, your agent can:

Build real games: scenes, scripts, physics and UI, through live MCP tools.
Build multiplayer games on Summer's own networking: matchmaking, parties, leaderboards, player data and world saves.
Add analytics to the game and read it back: store page views, launches, play sessions, play time and your own events.
Publish games to the summer.games store: the store page, art, the build, a private preview link and the release. Summer's automatic checks run before anything goes live; staff review games afterwards.
Use proven recipes: skills, templates and references, all searchable through one index.
Check its own work: play the game, take screenshots, read the debugger, press real keys.
Resume any project: .summer/ project memory lets a fresh agent pick up where the last one stopped.

You decide what your agent may do

Studio > Settings > Agent permissions has six switches. They apply to every app you connect, like Claude or ChatGPT. These defaults apply now. You can change them soon. Until then, Summer Games still asks the game's owner before an agent publishes, and price, A/B test and member changes ask you first.

Switch	Default	What the agent may do without asking
Make and build	on	Edit drafts, scenes, plans and uploads, and start builds.
Spend credits	on	Generate assets and run paid builds, within your credits and your auto top-up limit.
Publish	on	Publish store pages, versions and releases. Summer's automatic checks still run first.
Prices and live changes	on	Change prices and sales, start or stop A/B tests, change member roles.
Delete for good	off: asks	Delete games, assets, pages and releases.
Contact people	off: asks	Send invites and other emails to real people.

When a switch is off, the agent asks you first. It gives you a link (https://www.summerengine.com/studio/approvals/ ), and an open Studio tab shows the request with Approve and Decline. Nothing changes until you approve. The agent always asks before it changes agent permissions or auto top-up, enters a jam, or changes the analytics event limit. Studio > Settings > Agent activity lists what agents changed or asked for, newest first, with Undo for prices, sales, country prices, member roles, team names and the event limit.

Generation and paid builds spend your Summer credits. Turn on auto top-up in Studio Billing: when your credits fall below an amount you pick, Summer adds the amount you choose, up to a monthly limit you set. Agents can never change auto top-up on their own. When credits run out, your agent gets the error no_credits with one link: https://www.summerengine.com/studio/credits.

Summer never installs software without your explicit confirmation. Library entries are structurally prevented (by a capability lint in CI) from instructing agents to touch the network, credentials, or package managers.

Get started: one prompt

Open your AI agent (Claude Code, Cursor, Codex, Copilot, Devin Desktop, etc.) and paste:

Install Summer Engine and let's make a game. Read github.com/summerengine/summer, check what I already have installed, install whatever is missing, and open a starter project so we can start building.

The agent reads this README, checks what is already on your machine, and runs only the missing steps in its shell.

The first run will:

Fetch the summer-engine npm package (~2 MB) through npx.
Install Summer's game-dev skills into ~/.claude/skills/ (or your agent's user-skill directory) so the agent loads them next session.
Run npx -y summer-engine@latest dev: download the Summer Engine app (about 660 MB) if it's not installed, create a starter project and open it in the engine.

Building needs no sign-in. Your agent asks you to sign in only when you first use Summer's cloud (generating assets, publishing).

Agents with no shell (Claude Desktop, chat apps with the local server) do the same through the MCP: summer_projects_create_local writes the starter project and summer_projects_open_local opens it, after you say yes to installing the engine.

In most agents (Claude Code, Codex, Cursor, GitHub Copilot (VS Code, CLI, JetBrains), Zed, Cline, Kilo Code, OpenCode, Devin Desktop, Antigravity, Kiro, Trae, Warp, Goose, Hermes, Crush, Amp, Factory, Junie, Qwen Code, Kimi Code, Grok Build and Mistral Vibe), setup also connects Summer Games (summer-games), so the agent can see your friends, start parties and send messages as you. You sign in once; setup prints the step for your agent (Claude Code: /mcp, choose summer-games; Codex: /mcp login summer-games; Cursor: Connect next to summer-games in its MCP settings). A summer.games page opens in your browser; sign in and choose Allow.

Then ask the agent to build something.

Claude Code: the Summer plugin

In Claude Code, type:

/plugin install summer --marketplace summerengine/summer

Then type /summer:start. It gets a first game playing in about five minutes, with one OK from you and no sign-in: from a template that already plays, or from a plan of concept art Summer draws for your idea right in the chat, built in the Summer Engine desktop app. The plugin brings Summer's skills and two MCP servers: summer-engine drives the desktop app (needs Node), and summer-cloud is Summer's hosted server (sign in once with /mcp). Use the plugin or summer setup claude-code, not both: they install the same skills.

Only want assets?

Sound effects, music, voices, images, 3D models, motion and video are made on Summer's servers, so you do not need the Summer Engine app for them. The quickest way is the hosted server in Connect: no Node, no install. To get the asset skills too, paste this instead:

Connect Summer to this agent so I can make game assets. Read github.com/summerengine/summer, connect yourself to Summer and log me in. Skip the Summer Engine app and the starter project, I only want assets.

The agent installs the asset skills and the MCP config (summer-engine 4.0.0 or newer) and signs you in. It does not download the engine. Each a

Only the beginning is shown; read the rest in the repo

Summer Engine

Overview

PopNx MCP’s three pillars

What you can do with it

Install

Before you install

Or run it on your computer

Or run it on your computer

Or run it on your computer

Or run it on your computer

What it can do

Basic checksi

Maker matches the repo

Still maintained

Has a licence

Endpoint responds

Sign-in with OAuth

No hidden instructions in tool descriptions

Compared with others in Games, sports, food & learningi

Common questions

Alternatives

Neural Cosmology

slopped.site

Artsonia MCP

README from the maker

Summer Engine: MCP server, CLI and skills

The game engine built for AI.

Install

Connect

What this is

You decide what your agent may do

Get started: one prompt

Claude Code: the Summer plugin

Only want assets?