Roblox Studio MCP

MCP server for Roblox Studio: 29 tools over a push-based bridge, batched writes that undo as one step, editor-safe script edits. MIT.

Install

1. The Studio plugin

npx -y @el4cteo/rbx-studio-mcp --install-plugin

Or download StudioMCP.rbxmx from Releases into your Studio plugins folder.

2. The server, in whichever client you use:

<details> <summary><b>Claude Code</b></summary>

claude mcp add roblox-studio -- npx -y @el4cteo/rbx-studio-mcp

</details>

<details> <summary><b>Codex CLI</b></summary>

codex mcp add roblox-studio -- npx -y @el4cteo/rbx-studio-mcp

</details>

<details> <summary><b>Cursor</b> — <code>~/.cursor/mcp.json</code> or <code>.cursor/mcp.json</code></summary>

{
  "mcpServers": {
    "roblox-studio": {
      "command": "npx",
      "args": ["-y", "@el4cteo/rbx-studio-mcp"]
    }
  }
}

</details>

<details> <summary><b>Claude Desktop</b> — <code>claude_desktop_config.json</code></summary>

{
  "mcpServers": {
    "roblox-studio": {
      "command": "npx",
      "args": ["-y", "@el4cteo/rbx-studio-mcp"]
    }
  }
}

</details>

<details> <summary><b>Gemini CLI</b> — <code>~/.gemini/settings.json</code></summary>

{
  "mcpServers": {
    "roblox-studio": {
      "command": "npx",
      "args": ["-y", "@el4cteo/rbx-studio-mcp"]
    }
  }
}

</details>

<details> <summary><b>Windsurf</b> — <code>~/.codeium/windsurf/mcp_config.json</code></summary>

{
  "mcpServers": {
    "roblox-studio": {
      "command": "npx",
      "args": ["-y", "@el4cteo/rbx-studio-mcp"]
    }
  }
}

</details>

<details> <summary><b>VS Code / Copilot</b> — <code>.vscode/mcp.json</code></summary>

{
  "servers": {
    "roblox-studio": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "@el4cteo/rbx-studio-mcp"]
    }
  }
}

</details>

<details> <summary><b>opencode</b> — <code>opencode.json</code></summary>

{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "roblox-studio": {
      "type": "local",
      "command": ["npx", "-y", "@el4cteo/rbx-studio-mcp"],
      "enabled": true
    }
  }
}

</details>

3. Open Studio and accept the 127.0.0.1 prompt — the plugin connects automatically. Verify with studio_status.

4. debug additionally needs Debugger Luau API in File → Beta Features, plus a Studio restart. Nothing else requires it.

Port defaults to 44755 — change with --port or ROBLOX_STUDIO_MCP_PORT, and match it in the plugin widget. Loopback only.

Multiple agents

Register the server in as many clients as you like — the plugin connects out to one port, the first server owns it and the rest proxy through. No configuration, no second Studio connection.

Each agent keeps its own target (set_active_studio is per client), so two agents can work on two open places and neither can retarget the other. Pass studioId on a single call to reach elsewhere without changing your default.

Subagents share their parent's connection and therefore its target — a subagent calling set_active_studio silently retargets its parent. Give subagents an explicit studioId per call.

Tools

Session	studio_status list_studios set_active_studio
Discover	tree inspect find api
Scripts	script_read script_edit script_grep script_create
Instances	create modify delete move
World	geometry assets collision undo
Run & debug	playtest execute_luau character input console debug performance
Look	screenshot viewport device

Gotchas: during a playtest two sessions connect — pass studioId explicitly and use the edit session for anything that must persist. device emulation persists until device op="stop".

Batching

Every write tool takes an array — ten script edits or two hundred deletions is one call.

tool	takes	cap
create	instances, each nesting children to any depth	100
modify	entries, each with an unlimited list of paths	100 entries
delete	paths	200
move	moves	200
script_edit	edits, across any number of scripts	50
script_create	scripts	50
inspect	paths	50
input	input steps, delivered in order	40

modify caps entries, not targets — one entry can anchor five hundred parts, so pair it with find to change a whole place in one call.

Each batch is a single ChangeHistoryService recording: one Ctrl+Z. Batches are all-or-nothing — everything is transformed in memory first, so a failed match leaves the place untouched.

Parallel tool calls also work (responses are keyed by request id), but prefer a batch: N parallel calls are N round trips and N undo steps, a batch is one of each.

Compared to what else exists

	tools	transport	editor-safe writes	undo recording	live API dump	licence
this	29	SSE push	yes	yes	yes	MIT
Roblox built-in	~27	stdio	partial	—	n/a	closed source
Chrrxs	~40	poll	no	partial	no	MIT
drgost1	51	poll 500 ms	no	yes	no	MIT
boshyxd	43	long-poll	no	no	no	MIT (archived)
Roblox/studio-rust-mcp-server	2	HTTP	no	no	no	MIT (superseded)

• Push, not poll — 50 sequential round trips: 13.6 ms mean vs 25.8 ms, 12.8 ms median vs 29.9 ms (node scripts/latency.mjs --count 50 --compare).
• Safe script edits — ScriptEditorService:UpdateSourceAsync, not script.Source; your unsaved editor buffer survives.
• ~16k tokens of schema against 43–51 tools elsewhere. Cursor-paged, capped, detail: concise | standard | full.
• Live API dump — property typos get suggestions (Anchorred → Anchored).

Not built here: terrain, AI mesh and material generation.

Security

Binds 127.0.0.1, rejects Origin, and requires a header a browser cannot set cross-origin — closing the DNS-rebinding hole. HTTP permission is granted per plugin and per URL, so your experience's "Allow HTTP Requests" setting is untouched.

Development

npm install
npm run build          # TypeScript -> dist/
npm run build:plugin   # plugin/src -> build/StudioMCP.rbxmx
npm run install:plugin # build + copy into the Studio plugins folder
npm test               # plugin (Luau) + bridge (Node) tests

Needs luau, luau-compile and luau-analyze from the Luau releases on PATH or in tools/.

evals/ holds ten questions answerable only by driving a real Studio session — see evals/README.md.

Licence

MIT.