Summer Engine MCP guide
How to make games in LM Studio with Summer Engine
Use LM Studio as a free local MCP host: download a model, connect Summer Engine, and build playable games with no AI subscription. Summer Engine is the desktop game engine; LM Studio drives it through MCP with a model running on your own hardware.
Summer is free for MCP use
Download the desktop engine and connect it to your agent. The model runs on your own hardware, with no AI subscription and no per-message cost.
Open LM Studio
Run a free local model on your own GPU. The setup writes the MCP config so {agentLabel} can drive the engine directly.
Run a Summer game
The local model writes code. Summer Engine shows the Summer game, runs Play mode, and helps inspect errors. Export still requires the target templates and toolchains.
Install
Connect Summer to LM Studio
- 1
Install Summer Engine
Downloads the desktop engine app, about 1 GB. Skip it if Summer Engine is already installed, or if you only need assets and video for a game built in another engine.
- 2
Sign in
Opens your browser once. The CLI and the engine share the session.
- 3
Connect LM Studio
Writes the summer-engine MCP config and installs the Summer game-dev skills.
- 4
Restart and build
Open LM Studio, toggle on the summer-engine MCP server in the Program tab, and raise the loaded model's context length to 32k or higher.
Local setup notes
The 2026 specifics.
LM Studio is the whole stack
LM Studio is both the model runtime and an MCP host. The setup command writes ~/.lmstudio/mcp.json; toggle the summer-engine server on in the Program tab, and every engine call shows a confirmation dialog you can review before it runs.
Raise the context before you build
Models load with the context length baked into their metadata — often around 4k, which MCP tool schemas overflow silently. Set 32k or more when loading the model, and keep KV-cache quantization off for long agent sessions.
Models that hold up
gpt-oss-20b is the safe default on 12–16 GB of VRAM; Qwen3-Coder-30B and Gemma 4 27B are the 24 GB picks. On Apple Silicon, prefer the MLX builds — faster and more memory-efficient in long agentic loops.
Why this matters
LM Studio runs free on your hardware. Summer Engine shows the game.
A capable local model can operate a real engine through MCP. It opens scenes, places objects, runs the project and reads errors. Your GPU does the thinking, with no subscription and no per-token bill, and your prompts never leave your machine.