StudioSwitch

Choose which open Roblox Studio windows your AI assistant can use.

Roblox Studio's built-in MCP server connects every open Studio window to your MCP client (Claude, Cursor, VS Code, …). With three or four places open, the assistant has to pick a studio_id on every call, and it can easily run code in the wrong place.

StudioSwitch is a small Windows app that sits in between. Tick the places the assistant may see, star a default, and switch while you work: no closing Studio windows, no restarting the assistant.

• ✅ Hide places: unticked Studios disappear from list_roblox_studios, and any call aimed at one is refused before it reaches Studio.
• ⭐ Default place: calls that leave out studio_id go to your starred Studio (or the only ticked one).
• 🔁 One-click switch: Use only this one hides everything else and stars the selection.
• ⚡ Live: changes apply to sessions that are already running, on their next Studio call.
• 📋 Status at a glance: place name, place ID, Edit/Play mode, and whether each window is connected.
• 🧩 Works with several clients: finds the Roblox Studio entry in Claude, Claude Code, Cursor, VS Code, Windsurf and Gemini CLI configs.

Not affiliated with Roblox Corporation or Anthropic. StudioSwitch builds on the behaviour of Roblox's StudioMCP.exe 1.0 (September 2026); a future Studio update could change that.

How it works

flowchart LR
    C[MCP client<br/>Claude / Cursor / VS Code] -- stdio --> S[StudioSwitchShim.exe]
    S -- stdio --> M[StudioMCP.exe<br/>from Roblox]
    M -- ws 127.0.0.1:13469 --> A[Studio: Place A]
    M --> B[Studio: Place B]
    M --> D[Studio: Place C]
    U[StudioSwitch.exe<br/>window] -- writes --> F[(config.json)]
    S -. reads on every call .-> F

Loading

1. Hook rewrites the Roblox Studio server entry in your MCP client's config so it launches StudioSwitchShim.exe instead of Roblox's mcp.bat. Only that entry changes, a backup of the file is saved next to it, and Unhook restores the original byte-for-byte.
2. The shim starts the real StudioMCP.exe and relays everything unchanged, except that it:
   • filters the list_roblox_studios result down to the Studios you ticked, marks your default with "default": true, and notes how many are hidden;
   • refuses calls whose studio_id belongs to a hidden Studio;
   • fills in studio_id for calls that omit it (and marks it optional in the tool schemas).
3. The window reads live status through its own connection to the same local MCP hub and saves your choices to %LOCALAPPDATA%\StudioSwitch\config.json. The shim re-reads that file whenever it changes.

Studios are identified by place ID, so your choices survive closing and reopening a place.

Install

1. Download StudioSwitch.exe from the latest release and put it somewhere permanent.
2. Make sure Roblox Studio's MCP server is set up in your client (Studio → Assistant settings → MCP).
3. Run StudioSwitch.exe and click Hook.
4. Restart your MCP client once (e.g. fully quit and reopen the Claude app).

StudioSwitch adds itself to the Start menu the first time it runs, so afterwards you can open it from there. If you move the exe, the shortcut follows the next time you open it from the new location. Keep the window open while you work and tick or untick places as you go.

Windows SmartScreen may warn because the exe isn't code-signed. Choose More info → Run anyway, or build it yourself from source (below).

Build from source

Windows 10/11 already includes everything needed (the .NET Framework 4.x C# compiler). No SDK, no NuGet.

powershell -NoProfile -ExecutionPolicy Bypass -File build.ps1

This produces StudioSwitch.exe (with the shim embedded) and obj\StudioSwitchShim.exe.

Command line

StudioSwitch.exe                         open the window
StudioSwitch.exe status [config.json …]  show hook status of every known (or given) config
StudioSwitch.exe hook   [config.json …]  hook them
StudioSwitch.exe unhook [config.json …]  restore them

Supported MCP clients

Client	Config file
Claude app	%APPDATA%\Claude\claude_desktop_config.json
Claude app (Microsoft Store)	%LOCALAPPDATA%\Packages\Claude_*\LocalCache\Roaming\Claude\claude_desktop_config.json
Claude Code	%USERPROFILE%\.claude.json (global and per-project entries)
Cursor	%USERPROFILE%\.cursor\mcp.json
VS Code / Insiders	%APPDATA%\Code\User\mcp.json, %APPDATA%\Code - Insiders\User\mcp.json
Windsurf	%USERPROFILE%\.codeium\windsurf\mcp_config.json
Gemini CLI	%USERPROFILE%\.gemini\settings.json

An entry is recognised by what it runs (StudioMCP.exe, or mcp.bat in the Roblox folder), not by its name. Other clients work too: pass the config path to StudioSwitch.exe hook <path>.

Files StudioSwitch writes

Path	What
%LOCALAPPDATA%\StudioSwitch\config.json	your choices: {"hidden": [placeIds], "pinned": placeId}
%LOCALAPPDATA%\StudioSwitch\StudioSwitchShim.exe	the shim your clients launch
%LOCALAPPDATA%\StudioSwitch\hooks.json	original config entries, for Unhook
<config>.studioswitch-<timestamp>.bak	a copy of each config file before it was edited
%APPDATA%\Microsoft\Windows\Start Menu\Programs\StudioSwitch.lnk	Start menu shortcut to wherever the exe lives

Set STUDIOSWITCH_DIR to use a different folder instead of %LOCALAPPDATA%\StudioSwitch.

Troubleshooting

The assistant still sees a place I unticked. The client is still running the Studio MCP it started before you hooked. Restart it once. If the window shows not hooked again afterwards, the client rewrote its config on exit: click Hook and restart once more.

A Studio window shows "NOT connected". Turn the MCP server on in that window's Assistant settings, and make sure the place has finished loading.

"Access is denied" when starting StudioSwitch (or MCP tools stop working after hooking). Some hardened setups enable the Microsoft Defender attack surface reduction rule Block executable files from running unless they meet a prevalence, age, or trusted list criterion. A small unsigned tool can never meet it. Check Windows Security → Protection history; if that rule blocked StudioSwitch, an administrator can allow exactly its two files:

Add-MpPreference -AttackSurfaceReductionOnlyExclusions "C:\path\to\StudioSwitch.exe","$env:LOCALAPPDATA\StudioSwitch\StudioSwitchShim.exe"

Uninstall

Click Unhook (or run StudioSwitch.exe unhook), restart your MCP clients, then delete StudioSwitch.exe, %LOCALAPPDATA%\StudioSwitch and the Start menu shortcut (%APPDATA%\Microsoft\Windows\Start Menu\Programs\StudioSwitch.lnk).

Tests

py tests\test_hooks.py                                    # synthetic configs in a temp folder
py tests\test_shim.py "$env:LOCALAPPDATA\StudioSwitch\StudioSwitchShim.exe"   # needs 2+ Studio windows open

Both use a temporary STUDIOSWITCH_DIR, so your real settings and configs are never touched. The shim test's only action inside Studio is a read-only return game.PlaceId.

License

MIT