The bridge is an addonthat runs inside s&box; its tools are served by the editor's built-in MCP server over local HTTP (on by default: Editor → Preferences → MCP Server). Install the addon once, then connect the Claude side. No Node.js required.
Install it from the s&box Asset Library. s&box drops it into your project's Libraries/claudebridge/ automatically.
One command. From v2.0.0 it registers bothMCP servers: the editor's native endpoint and the optional lifeline, and bundles the cookbook brain, the specialist agent, the screenshot workflow skill, and onboarding: the full experience.
/plugin marketplace add LouSputthole/Sbox-Claude
/plugin install sbox-claudeThen restart Claude Code (or run /reload-plugins).
The editor hosts the MCP server itself (streamable HTTP, loopback-only, port 7269), so any MCP client can connect, no Node.js required. You just wire the brain in yourself:
claude mcp add --transport http sbox http://127.0.0.1:7269/mcpOptional but recommended: add the lifeline: a slim diagnostics server that keeps answering (logs, compile errors, docs) when the editor crashes and takes the native server with it. This one does need Node.js 18+:
claude mcp add sbox-lifeline -- npx -y sbox-mcp-server@2 --lifelineWith s&box open on your project, ask Claude “Check the bridge status”, you want the bridge_* toolsets visible and a healthy handler count. Then try “Create a cube at 0, 0, 100 with a box model.”
The Claude Bridge dock (View → Claude Bridge) gives a status readout, but you do not need to keep it open. Since v1.3 the bridge runs on a static frame handler that processes requests with the dock closed.
Once it's connected, you just talk to Claude in your project folder, no commands to memorize.
Plain English; Claude writes the C#, wires it up, and checks its own work.
This is where the cookbook brain kicks in and builds it the way shipped games do.
For anything visual, Claude aims a camera and screenshots it. The PNG arrives inline in the tool result, so it sees the image immediately and fixes the angle/lighting before showing you. For multiplayer it runs networking_lint + inspect_networked_object. You don't have to ask, the sbox-build-feature skill enforces the build → screenshot → verify → fix loop.
For a self-contained feature, point Claude at the bundled sbox-game-dev agent: “Use the sbox-game-dev agent to build a wave-survival mode with a round timer, escalating spawns, and a HUD.”
The brain: code-grounded recipes mined from 51 shipped open-source s&box games. Genre playbooks, system how-tos, engine references.
Correct s&box C#: Unity→s&box translation, the rules, and component/UI/networking/physics references. Stops Unity-pattern hallucination.
The screenshot-driven build → verify → fix workflow, so Claude isn't building blind.
Turn one ask into a playable starter scene; a wizard checks the bridge and your libraries on first connect.
You can also invoke any skill explicitly, e.g. /sbox-claude:sbox-build-feature.
.scene files in Git.