# SimEngine

> SimEngine is a pre-release, general-purpose C++20 / Vulkan 1.3 game engine built for coding agents. Agents drive it from the command line: typed commands, seeded headless scenarios, offscreen captures and one JSON document per command. No LLM in the runtime. MIT OR Apache-2.0; the repository opens with the first distributable milestone.

There is no hosted API, no API key and no MCP server: SimEngine is a set of local executables. Any agent that can run a shell command and read JSON can use it. You cannot ship a game with it yet (no supported physics, game loop, input or audio).

## Start here

- [Agent guide](https://indiega.me/simengine/agent-guide.md): setup, the agent loop, implementation contract, scenario format, run artifacts, session protocol, skills and exit codes.
- [Copy-ready agent prompt](https://indiega.me/simengine/agent-prompt.txt): set up the engine, create a first scene, change it and prove the change.
- [CLI reference](https://indiega.me/simengine/cli.md): every command and option of simengine_host, simengine_capture, simengine_desktop and the example driver.
- [Full context](https://indiega.me/simengine/llms-full.txt): all of the above in one document.

## Skills

- [simengine-create-project](https://indiega.me/simengine/skills/simengine-create-project/SKILL.md)
- [simengine-modify-scene](https://indiega.me/simengine/skills/simengine-modify-scene/SKILL.md)
- [simengine-run-capture-diagnose](https://indiega.me/simengine/skills/simengine-run-capture-diagnose/SKILL.md)

## Examples

- [first_scene scenario](https://indiega.me/simengine/examples/first_scene/scenario.json): the reference scenario (schema simengine.scenario v1).

## Pages

- [SimEngine](https://indiega.me/simengine): spec sheet, architecture, scale, roadmap.
- [AI game engine](https://indiega.me/ai-game-engine): what an AI game engine is, comparison with Unity, Unreal and Godot, FAQ.
- [Docs](https://indiega.me/simengine/docs): the human-readable version of these files.
- [Why we built SimEngine](https://indiega.me/blog/why-we-built-simengine)