Roblox MCP

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mutate_instances

Create, delete, clone, move, rename, or pivot Roblox instances. Supports batch operations for efficient editing.

Instructions

Create, delete, clone, move, rename, or pivot instances. [PRO] create_tree, mass_create, mass_delete, mass_duplicate, smart_duplicate.

Input Schema

TableJSON Schema

Name	Required	Description
`action`	Yes	Mutation action. Basic: create, create_with_props, delete, clone, move, rename, pivot. [PRO]: create_tree, mass_create, mass_delete, mass_duplicate, smart_duplicate.
`contextId`	No	Optional execution context identifier. Used to continue an existing context for mutating actions.
`contextSummary`	No	Optional structured execution context attached to this tool call.
`replayMetadata`	No	Optional replay-ready metadata attached to this tool call.
`className`	No	Roblox class name (e.g., Part, Script, Folder). Used by: create, create_with_props.
`parent`	No	Parent path for new instance. Used by: create, create_with_props.
`name`	No	Name for the instance. Used by: create (optional), create_with_props (required).
`properties`	No	Properties to set on the instance. Supports Vector3, Color3, CFrame, UDim2, Enum types. Used by: create (optional), create_with_props (required).
`path`	No	Instance path to operate on. Used by: delete, clone (as sourcePath), move, rename, pivot, smart_duplicate.
`sessionDebugId`	No	Optional same Studio/plugin session debug identity for verifying a duplicate-named target. Used by: delete, clone, move, rename, pivot, smart_duplicate.
`siblingIndex`	No	Optional 1-based same-name sibling index fallback for verifying a duplicate-named target. Used by: delete, clone, move, rename, pivot, smart_duplicate.
`sourcePath`	No	Source instance path to clone from. Used by: clone. Alternative to path.
`targetParent`	No	Target parent for cloned/duplicated instances. Used by: clone, mass_duplicate, smart_duplicate.
`newName`	No	New name for instance. Used by: rename (required), clone (optional).
`newParent`	No	New parent path to move instance to. Used by: move.
`position`	No	Target position as Vector3 {x, y, z}. Used by: pivot.
`cframe`	No	Target CFrame as 12-number array [x, y, z, r00, r01, r02, r10, r11, r12, r20, r21, r22]. Used by: pivot.
`offset`	No	Relative offset to move by (ignores position/cframe). Used by: pivot, smart_duplicate.
`tree`	No	[PRO] Instance tree specification for hierarchical creation. Used by: create_tree.
`instances`	No	[PRO] Array of instance specifications for batch creation. Used by: mass_create. Each item: {className, name, parentPath, properties?}.
`paths`	No	[PRO] Array of instance paths. Used by: mass_delete, mass_duplicate.
`count`	No	[PRO] Number of copies to create. Used by: smart_duplicate.

Schema Changelog

Changes observed during successful MCP inspections.

Changed6 schema fields changedv2.7.5May 12, 2026

addedInput schema / properties / contextId

Added value: +{
+  "description": "Optional execution context identifier. Used to continue an existing context for mutating actions.",
+  "type": "string"
+}

addedInput schema / properties / contextSummary

Added value: +{
+  "description": "Optional structured execution context attached to this tool call.",
+  "properties": {
+    "affectedAreas": {
+      "items": {
+        "properties": {
+          "kind": {
+            "enum": [
+              "script",
+              "instance",
+              "property",
+              "system",
+              "gameplay",
+              "ui",
+              "terrain",
+              "lighting",
+              "asset",
+              "other"
+            ],
+            "type": "string"
+          },
+          "label": {
+            "type": "string"
+          },
+          "target": {
+            "type": "string"
+          }
+        },
+        "required": [
+          "kind",
+          "target",
+          "label"
+        ],
+        "type": "object"
+      },
+      "type": "array"
+    },
+    "expectedBehavior": {
+      "type": "string"
+    },
+    "intent": {
+      "type": "string"
+    },
+    "observedBehavior": {
+      "type": "string"
+    },
+    "testScenario": {
+      "type": "string"
+    }
+  },
+  "type": "object"
+}

addedInput schema / properties / replayMetadata

Added value: +{
+  "description": "Optional replay-ready metadata attached to this tool call.",
+  "properties": {
+    "artifactRefs": {
+      "items": {
+        "type": "string"
+      },
+      "type": "array"
+    },
+    "assertionRefs": {
+      "items": {
+        "type": "string"
+      },
+      "type": "array"
+    },
+    "inputRefs": {
+      "items": {
+        "type": "string"
+      },
+      "type": "array"
+    },
+    "mode": {
+      "type": "string"
+    },
+    "seed": {
+      "type": "number"
+    },
+    "setupRefs": {
+      "items": {
+        "type": "string"
+      },
+      "type": "array"
+    },
+    "timeout": {
+      "type": "number"
+    }
+  },
+  "type": "object"
+}

addedInput schema / properties / sessionDebugId

Added value: +{
+  "description": "Optional same Studio/plugin session debug identity for verifying a duplicate-named target. Used by: delete, clone, move, rename, pivot, smart_duplicate.",
+  "type": "string"
+}

addedInput schema / properties / siblingIndex

Added value: +{
+  "description": "Optional 1-based same-name sibling index fallback for verifying a duplicate-named target. Used by: delete, clone, move, rename, pivot, smart_duplicate.",
+  "type": "number"
+}

removedInput schema / properties / spacing

Removed value: -{
-  "description": "[PRO] Spacing between duplicated instances. Used by: smart_duplicate. Alias for offset.",
-  "properties": {
-    "x": {
-      "type": "number"
-    },
-    "y": {
-      "type": "number"
-    },
-    "z": {
-      "type": "number"
-    }
-  },
-  "type": "object"
-}

First observedv2.0.1Mar 24, 2026

TDQS

B3.4/5.0

Behavior2/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full burden of transparency. It mentions destructive actions (delete) but does not disclose side effects, authorization needs, rate limits, or that some actions are irreversible.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness4/5

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is concise (two lines, front-loaded with actions). However, it could be slightly more structured to group actions clearly.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness3/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the high parameter count (22) and multiple actions, the description does not adequately explain the overall tool behavior or how to select among actions. The schema covers details, but the description lacks high-level context.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the parameter descriptions in the schema are thorough. The tool description adds no additional meaning beyond listing actions; it does not explain how parameters relate to actions.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description clearly states the tool performs multiple mutation actions (create, delete, clone, move, rename, pivot) on instances. It lists specific actions and distinguishes PRO features, making the purpose immediately obvious.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines3/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies this tool is for mutating instances but provides no explicit guidance on when to use it versus alternatives like query_instances. It does not mention exclusions or prerequisites.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

mutate_instances

Instructions

Input Schema

Schema Changelog

TDQS

Other Tools