robloxstudio-mcp

Start playtest. Captures print/warn/error via LogService. Poll with get_playtest_output, end with stop_playtest. Use numPlayers for multi-client testing (server + N clients).

Diff two instances by comparing their properties. Useful for debugging why a duplicate behaves differently.

Remove a tag

Undo the last change in Roblox Studio. Uses ChangeHistoryService to reverse the most recent operation.

Search for MaterialVariant instances in MaterialService by name. Use this to find custom materials before using them in generate_build or create_build palettes. Returns material names and their base material types.

Create multiple instances. Each can have optional properties.

Delete an instance

Get an attribute value

Stop playtest and return all captured output.

Import a build into Roblox Studio. Accepts either a full build data object OR a library ID string (e.g. "medieval/church_01") to load from the build library. When using generate_build or create_build, pass the build ID string instead of the full data.

Get the Studio output log history. Works in both edit and play mode.

Run syntax analysis on Luau scripts using loadstring. Detects compile errors with line numbers. Pass a script path to analyze one script, or a container path to analyze all scripts under it.

Get all attributes on an instance

Get available services and their children

Clone an instance to a new parent location. Creates a deep copy of the instance and all its descendants.

Get all instances with a specific tag

Search instances by name, class, or script content

Redo the last undone change in Roblox Studio. Uses ChangeHistoryService to reapply the most recently undone operation.

Capture a screenshot of the Roblox Studio viewport and return it as a PNG image. Requires EditableImage API to be enabled: Game Settings > Security > "Allow Mesh / Image APIs". Only works in Edit mode with the viewport visible.

Get full game hierarchy tree. Increase maxDepth (default 3) for deeper traversal.

Batch smart_duplicate operations

Create a new build model from scratch and save it to the library. Define parts using compact arrays [posX, posY, posZ, sizeX, sizeY, sizeZ, rotX, rotY, rotZ, paletteKey, shape?, transparency?]. Palette maps short keys to [BrickColor, Material] pairs. The build is saved and can be referenced by import_build or import_scene.

Move the player character to a target position or instance during playtest. Uses PathfindingService for automatic navigation around obstacles, falling back to direct movement. Requires an active playtest in "play" mode. Does NOT simulate player input — moves the character directly.

Execute Luau code in plugin context. Use print()/warn() for output. Return value is captured.

List all connected plugin instances with their roles. Use during multi-client playtest to discover server and client instances for targeted commands.

Get all currently selected objects

Delete an attribute

Get all tags on an instance

List available builds in the local build library. Returns build IDs, styles, bounds, and part counts. Optionally filter by style.

Get detailed marketplace metadata for a specific asset. Uses ROBLOX_OPEN_CLOUD_API_KEY or falls back to ROBLOSECURITY cookie (own assets only).

Set a property on an instance

Create a new instance. Optionally set properties on creation.

Search the Creator Store (Roblox marketplace) for assets by type and keywords. Requires ROBLOX_OPEN_CLOUD_API_KEY env var (no cookie auth for this endpoint).

Duplicate with naming, positioning, and property variations

Add a tag

Export a Model/Folder into a compact, token-efficient build JSON format and auto-save it to the local build library. The output contains a palette (unique BrickColor+Material combos mapped to short keys) and compact part arrays with positions normalized relative to the bounding box center. The file is saved to build-library/{style}/{id}.json automatically.

Import a full scene layout. Provide a scene with model references (resolved from library) and placement data. Each model is placed at the specified position/rotation. Can also include inline custom builds.

Find and replace text across all scripts in the game. Supports literal and Lua pattern matching. Use dryRun to preview changes before applying. Pairs with grep_scripts for search-only operations.

Get a property from multiple instances

Set an attribute. Supports primitives, Vector3, Color3, UDim2, BrickColor.

Get properties/methods for a class

Get a build from the library by ID. Returns metadata, palette, and generator code (if the build was created with generate_build). IMPORTANT: When the user asks to modify an existing build, ALWAYS call get_build first to retrieve the original code, then make targeted edits to only the relevant lines, and call generate_build with the modified code. Never rewrite the entire code from scratch — only change what the user asked to change.

Get instance hierarchy tree from Studio

Set a property on multiple instances

Set multiple attributes on an instance in a single call. More efficient than repeated set_attribute calls.

Procedurally generate a build via JS code. ALWAYS generate the entire scene in ONE call — never split into multiple small builds. PREFER high-level primitives over manual loops. No comments. No unnecessary variables. Maximize build detail per line. EDITING: When modifying an existing build, call get_build first to retrieve the original code. Then make ONLY the targeted changes the user requested — do not rewrite unchanged code. Pass the modified code to generate_build. HIGH-LEVEL (use these first — each replaces 5-20 lines): room(x,y,z, w,h,d, wallKey, floorKey?, ceilKey?, wallThickness?) - Complete enclosed room (floor+ceiling+4 walls) roof(x,y,z, w,d, style, key, overhang?) - style: "flat"|"gable"|"hip" stairs(x1,y1,z1, x2,y2,z2, width, key) - Auto-generates steps between two points column(x,y,z, height, radius, key, capKey?) - Cylinder with base+capital pew(x,y,z, w,d, seatKey, legKey?) - Bench with seat+backrest+legs arch(x,y,z, w,h, thickness, key, segments?) - Curved archway fence(x1,z1, x2,z2, y, key, postSpacing?) - Fence with posts+rails BASIC: part(x,y,z, sx,sy,sz, key, shape?, transparency?) rpart(x,y,z, sx,sy,sz, rx,ry,rz, key, shape?, transparency?) wall(x1,z1, x2,z2, height, thickness, key) — vertical plane from (x1,z1) to (x2,z2) floor(x1,z1, x2,z2, y, thickness, key) — horizontal plane at height y, corners (x1,z1)-(x2,z2). NOT fill — only takes 2D corners+y, not 3D points fill(x1,y1,z1, x2,y2,z2, key, [ux,uy,uz]?) — 3D volume between two 3D points beam(x1,y1,z1, x2,y2,z2, thickness, key) IMPORTANT: Palette keys must match exactly. Use only keys defined in your palette object, not color names. CUSTOM MATERIALS: Use search_materials to find MaterialVariant names, then reference them as the 3rd palette element: {"a": ["Color", "BaseMaterial", "VariantName"]}. REPETITION: row(x,y,z, count, spacingX, spacingZ, fn(i,cx,cy,cz)) grid(x,y,z, countX, countZ, spacingX, spacingZ, fn(ix,iz,cx,cy,cz)) Shapes: Block(default), Wedge, Cylinder, Ball, CornerWedge. Max 10000 parts. Math and rng() available. CYLINDER AXIS: Roblox cylinders extend along the X axis. For upright cylinders, use size (height, diameter, diameter) with rz=90. The column() primitive handles this automatically. EXAMPLE — compact cabin (17 lines): room(0,0,0,8,4,6,"a","b","a") roof(0,4,0,8,6,"gable","c") wall(-4,0,-2,4,0,-2,4,1,"a") part(0,2,3,3,3,0.3,"a","Block",0.4) row(-2,0,-1,3,0,2,(i,cx,cy,cz)=>{pew(cx,0,cz,3,2,"d")}) column(-3,0,-2,4,0.5,"a","b") column(3,0,-2,4,0.5,"a","b") part(0,2,0,2,1,1,"b")

Find instances by name, class, or properties

Ripgrep-inspired search across all script sources. Supports literal and Lua pattern matching, context lines, early termination, and results grouped by script with line/column numbers.

Get all descendants of an instance recursively with depth info. More efficient than repeated get_instance_children calls.

Insert lines after a given line number (0 = beginning).

Replace exact text in a script. old_string must match exactly once in the script (whitespace-sensitive). Use get_script_source first to see current content.

Find objects with specific property values

Poll output buffer without stopping. Returns isRunning and captured messages.

Rename an instance.

Get the thumbnail image for an asset as base64 PNG, suitable for vision LLMs. Thumbnails API is public but asset validation uses ROBLOX_OPEN_CLOUD_API_KEY.

Replace entire script source. For partial edits use edit/insert/delete_script_lines.

Preview a Roblox asset without permanently inserting it. Loads the asset, builds a hierarchy tree with properties and summary stats, then destroys it. Useful for inspecting asset contents before insertion.

Get place ID, name, and game settings

Get children and their class types

Simulate keyboard input via VirtualInputManager. Use during playtest for character movement (W/A/S/D), jumping (Space), interactions (E), or any key-driven action. For sustained movement, use "press" to hold and "release" to let go.

Simulate mouse input in the Roblox Studio viewport via VirtualInputManager. Use during playtest to click UI buttons, interact with objects, or navigate menus. Coordinates are viewport pixels (top-left is 0,0). Use capture_screenshot to identify UI element positions before clicking.

Delete a range of lines. 1-indexed, inclusive.

Set multiple properties on a single instance in one call.

Get all properties of an instance

Create an entire instance hierarchy from a nested JSON tree in one call.

Get script source. Returns "source" and "numberedSource" (line-numbered). Use startLine/endLine for large scripts.

Upload an image file as a Decal asset to Roblox. Supports ROBLOSECURITY cookie auth (recommended, simpler) or ROBLOX_OPEN_CLOUD_API_KEY (needs asset:write scope + creator ID). Cookie auth is used automatically when ROBLOSECURITY is set.

Move (reparent) an instance to a new parent location. Preserves all children and properties.

Insert a Roblox asset into Studio by loading it via AssetService and parenting it to a target location. Optionally set position.