rbx-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.

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

Or downloadStudioMCP.rbxmxfromReleasesinto your Studio plugins folder.

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

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

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

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

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

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

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

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

3.Open Studio and accept the127.0.0.1prompt — the plugin connects automatically. Verify withstudio_status.

4.debugadditionally needsDebugger Luau APIin File → Beta Features, plus a Studio restart. Nothing else requires it.

Port defaults to44755— change with--portorROBLOX_STUDIO_MCP_PORT, and match it in the plugin widget. Loopback only.

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_studiois per client), so two agents can work on two open places and neither can retarget the other. PassstudioIdon a single call to reach elsewhere without changing your default.

Subagents share their parent's connection and therefore its target — a subagent callingset_active_studiosilently retargets its parent. Give subagents an explicitstudioIdper call.

Gotchas: during a playtest two sessions connect — passstudioIdexplicitly and use the edit session for anything that must persist.deviceemulation persists untildevice op="stop".

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

modifycapsentries, not targets — one entry can anchor five hundred parts, so pair it withfindto change a whole place in one call.

Each batch is a singleChangeHistoryServicerecording: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.

- 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, notscript.Source; your unsaved editor buffer survives.
- ~16k tokens of schemaagainst 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.

Binds127.0.0.1, rejectsOrigin, 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.

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

Needsluau,luau-compileandluau-analyzefromthe Luau releasesonPATHor intools/.

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

Local stdio MCP server that lets AI coding agents read and maintain structured architecture, rules, and decisions directly from your repository.