# 🕹️ Agents Plugins
**The CS Modding marketplace (`csmodding`) of agent plugins for Claude Code and OpenAI Codex CLI.**
Give your coding agent **eyes and hands inside a running game**: its HTML UI, and its C#/ECS
internals.
Generic tooling, developed and verified against Cities: Skylines II.
Encourage my work by putting a star ⭐ if it has been useful to you!
[](https://github.com/CitiesSkylinesModding/agents-plugins/actions/workflows/ci.yml)
[](https://www.npmjs.com/package/@csmodding/gameface-devtools-mcp)
[](LICENSE)
[Plugins](#plugins) · [Install](#install) · [Development](#development)
---
## Plugins
| Plugin | Give your agent… | Runs on | Docs |
| --- | --- | --- | --- |
| 🔬 **[unity-devtools](plugins/unity-devtools/README.md)** | A live line into a **Unity Mono dev build** over the Mono Soft Debugger: see the rendered frame, reflect types, evaluate C# expressions, read & write ECS state. No code injection. Plus a driving skill. | .NET 10 SDK (Windows, Linux) | [README](plugins/unity-devtools/README.md) · [Tools reference](plugins/unity-devtools/README.md#tools) · [NuGet](https://www.nuget.org/packages/UnityDevtools.Mcp) |
| 🖼️ **[coherent-gameface](plugins/coherent-gameface/README.md)** | Eyes and hands in any **Coherent Gameface** (Cohtml) game UI over CDP: evaluate JS, screenshot, drive the DOM, console, JS breakpoints. Plus an engine skill and a driving skill. | Node 22.4+ | [README](plugins/coherent-gameface/README.md) · [Why](plugins/coherent-gameface/WHY.md) · [Tools reference](plugins/coherent-gameface/mcp/README.md) · [npm](https://www.npmjs.com/package/@csmodding/gameface-devtools-mcp) |
| 📚 **[cs2-modding](plugins/cs2-modding/README.md)** | How **Cities: Skylines II** is built and how a mod changes it: the game's architecture, the modding techniques and the game mechanics behind them, every claim checked against the game itself, with unconfirmed claims marked. Plus the `cs2-dev` MCP server, which restarts the game, waits on it, reports its errors, and runs a mod's in-game scenarios. | Node 22.4+ | [README](plugins/cs2-modding/README.md) · [Tools reference](plugins/cs2-modding/README.md#the-server) |
The two toolkit plugins are **generic**: they target any game or application embedding the
technology, with Cities: Skylines II as the reference target where everything is field-verified.
`cs2-modding` is the deliberate exception, and is about that game throughout.
> [!IMPORTANT]
> **Coherent Labs published their own Gameface MCP — which should you use?** Theirs is built around
> a `Player.exe` from a licensed Gameface SDK; this one attaches to a game that is already running.
> [**Read the full comparison →**](plugins/coherent-gameface/WHY.md)
> [!TIP]
> **Not using Claude Code or Codex CLI?** The Gameface MCP server is also published on npm as
> [`@csmodding/gameface-devtools-mcp`](https://www.npmjs.com/package/@csmodding/gameface-devtools-mcp)
> and works with any MCP client (Cursor, Gemini CLI, VS Code, …).
## Install
Add the marketplace once, then install the plugin(s) you want. Each plugin that carries an MCP
server autoloads it, version-locked to the plugin, with no setup step of your own. How it gets
there differs: `coherent-gameface` and `cs2-modding` run a bundle committed alongside the plugin,
so they need nothing but Node and work offline. `unity-devtools` needs the .NET 10 SDK and fetches
its server from NuGet the first time it launches, then caches it.
### Claude Code
```
/plugin marketplace add CitiesSkylinesModding/agents-plugins
/plugin install coherent-gameface@csmodding
/plugin install unity-devtools@csmodding
/plugin install cs2-modding@csmodding
```
Or from your terminal, `claude plugin marketplace add …` / `claude plugin install …` with the same
arguments.
### Codex CLI
```sh
codex plugin marketplace add CitiesSkylinesModding/agents-plugins
codex plugin add coherent-gameface@csmodding
codex plugin add unity-devtools@csmodding
codex plugin add cs2-modding@csmodding
```
Then run `/mcp` to confirm the servers connected. Each plugin's README covers its requirements,
configuration and troubleshooting.
## Development
Uses `mise` + `bun` (never `npx`). The repository is a marketplace: plugin sources live under
`plugins//`, and everything a plugin ships lives inside its directory. The root is a bun
workspace carrying the lint/format tooling (oxlint, oxfmt) and the lefthook git hooks; the
Gameface and `cs2-dev` MCP servers are the `plugins/coherent-gameface/mcp/` and
`plugins/cs2-modding/mcp/` workspace packages, and the Unity MCP server is a .NET solution
(`agents-plugins.slnx`).
```sh
bun install # install all workspace deps (also installs the git hooks)
mise check # verify (read-only): type-check, lint, format
mise fix # auto-fix lint + format in place
mise build # rebuild every shipped artifact (commit the results)
```
The unity-devtools integration tests need Mono and skip without it; on Linux, install `mono-devel`
(`mono-runtime` alone lacks the facade assemblies they load).
Run `mise tasks` for the full list, and see [`AGENTS.md`](AGENTS.md) (plus each plugin's own
`AGENTS.md`) for the architecture notes.