Plugin & setup

The bridge is two pieces: the addonthat runs inside s&box, and the MCP server that links Claude to it over local file IPC. Install the addon once, then connect the Claude side.

Install

1. Install the addon — everyone

Install it from the s&box Asset Library. s&box drops it into your project's Libraries/claudebridge/ automatically.

2A. Connect with the Claude Code plugin (recommended)

One command. It registers + auto-updates the MCP server 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-claude

Then restart Claude Code (or run /reload-plugins).

2B. Or connect manually — any MCP client

Works with any MCP client (not just Claude Code) — you just wire the brain in yourself. Needs Node.js 18+.

claude mcp add sbox -- npx sbox-mcp-server@latest

3. Verify

In your project folder, ask Claude “Check the bridge status” — you want connected: true with a live 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.

Using the plugin

Once it's connected, you just talk to Claude in your project folder — no commands to memorize.

1. Describe what you want

Plain English; Claude writes the C#, wires it up, and checks its own work.

“Add a double-jump and a sprint with a stamina bar.”
“Make the campfire flicker and cast warm light at night.”
“Spawn 5 patrolling guards that chase the player on sight.”

2. Ask for whole systems by name

This is where the cookbook brain kicks in and builds it the way shipped games do.

“Build me a host-authoritative shop with a currency wallet.”
“Give me a save system with autosave and versioned saves.”
“Add an inventory with a hotbar and drag-and-drop.”

3. Let it verify itself

For anything visual, Claude aims a camera, screenshots it, reads the result back, 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.

4. Hand off big tasks to the specialist agent

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.”

What the plugin bundles

sbox-cookbook

The brain — code-grounded recipes mined from 51 shipped open-source s&box games. Genre playbooks, system how-tos, engine references.

sbox-api

Correct s&box C# — Unity→s&box translation, the rules, and component/UI/networking/physics references. Stops Unity-pattern hallucination.

sbox-build-feature

The screenshot-driven build → verify → fix workflow, so Claude isn't building blind.

sbox-scaffold-game + onboarding

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.

Tips for best results

• Use the plugin — the brain + agent + screenshot skill is most of the value, and it's one command.
• Save before a big batch (Ctrl+S), then turn Claude loose. Keep .scene files in Git.
• Ask for systems by name so the brain routes you to a proven recipe.
• Don't edit the scene during play mode — the bridge refuses it with a clear message.

Stuck? See Troubleshooting or the FAQ.