Open source · MIT

Use Summer Engine
from any AI agent.

Open-source MCP server, 37 engine tools, and 20 game-dev skills. One install, every coding agent. Free.

Or paste this into your agent: "Install Summer Engine and let's make a game."

claude-code · summer
$ npx -y summer-engine@latest doctor
Detecting harness... Claude Code
Engine: Summer Engine 0.5.29 ✓
MCP server: ready on localhost:6550 ✓
20 skills loaded ✓
Summer Engine is ready.
> add a third-person character controller with double jump
→ Reading skill: character-controllers
→ summer_create_scene player.tscn
→ summer_add_node CharacterBody3D
→ summer_play scene
Player controller running. Try moving.
LIVE

Works with every coding agent

Claude Code
Cursor
Codex CLI
Gemini CLI
Windsurf
Cline
Roo
Copilot CLI
Factory Droid
OpenCode

What you get

One package, three layers.

37

Engine tools

Direct MCP bridge to a running Summer Engine. Create scenes, add nodes, set properties, run the game, read errors, generate assets, inspect resources.

20

Game-dev skills

Short markdown discipline guides. They auto-fire on intent so the agent reads production patterns before writing code, not after.

1

CLI

summer install · login · run · create · doctor · skills · mcp. Bootstraps your harness, handles auth, and runs the engine headlessly when an agent needs it.

How it works

Agent ↔ MCP ↔ Engine.

01

Your agent

Claude Code, Cursor, Codex, or any agent that speaks MCP. You write prompts, the agent picks tools and skills.

02

MCP server

Local Node process. Ships 37 tools the agent can call. Speaks to the engine over localhost:6550.

03

Summer Engine

AI-native game engine compatible with Godot 4. Receives ops, runs scenes, returns diagnostics. You see results live.

Frequently asked

Common questions

What is the Summer Engine MCP?
An open-source MCP (Model Context Protocol) server plus a library of game-dev skills that lets AI coding agents work inside a running Summer Engine instance. Install it once and every agent you use, Claude Code, Cursor, Codex, Gemini, gets the same toolset for building games.
Do I need Summer Engine installed?
Yes. Download Summer Engine first at https://www.summerengine.com/download. The CLI then bootstraps the MCP server and connects your agent to the running engine on localhost:6550.
Is it really free?
The plugin (MCP server + skills + CLI) is MIT licensed. The Summer Engine desktop app is free to download. Heavy cloud asset generation (3D models, animation, audio) is usage-based, with a free monthly credit pool.
Which agents does it support?
Claude Code, Cursor, Codex CLI, Gemini CLI, Windsurf, Cline, Roo, Copilot CLI, Factory Droid, and OpenCode. Any agent that speaks MCP works.
What can the skills do?
Skills are short markdown playbooks that auto-fire on intent. They cover 20 game-dev disciplines, from character controllers and multiplayer to shaders, post-processing, and Steam deployment. Each one is a discipline guide an agent reads before writing code, so you get production patterns instead of one-shot snippets.
Can I contribute a skill?
Yes. The repo lives at https://github.com/SummerEngine/summer. Run `summer skills create` in the CLI and it scaffolds a new skill folder you can PR.

Open the editor your agent already lives in.

Free, MIT licensed, and ready in a single command. Star the repo if you want updates, or paste the install line into your agent and start building.

Read the docs on github.com/SummerEngine/summer.