Roblox Motion Tools

by yansha-os

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TypeScript

Local

motion library save

motion_library_save

Validate and save custom or revised animation/VFX recipes for Roblox; use parentId to preserve revision lineage.

Instructions

Validate and save a custom recipe or revised recipe. Supply parentId to preserve revision lineage. All positions are local units; rotations are local XYZ degrees; key times are seconds.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`recipe`	Yes
`parentId`	No

Output Schema

TableJSON Schema

Name	Required	Description	Default
`result`	No

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedv1.0.0Sep 12, 2026

changedInput schema / properties / recipe / anyOf

Previous value: -[
-  {
-    "additionalProperties": false,
-    "properties": {
-      "duration": {
-        "maximum": 30,
-        "minimum": 0.1,
-        "type": "number"
-      },
-      "kind": {
-        "const": "animation",
-        "type": "string"
-      },
-      "loop": {
-        "type": "boolean"
-      },
-      "markers": {
-        "default": [],
-        "items": {
-          "additionalProperties": false,
-          "properties": {
-            "name": {
-              "$ref": "#/properties/recipe/anyOf/0/properties/name"
-            },
-            "time": {
-              "maximum": 30,
-              "minimum": 0,
-              "type": "number"
-            }
-          },
-          "required": [
-            "name",
-            "time"
-          ],
-          "type": "object"
-        },
-        "maxItems": 100,
-        "type": "array"
-      },
-      "name": {
-        "maxLength": 80,
-        "minLength": 1,
-        "type": "string"
-      },
-      "tracks": {
-        "items": {
-          "additionalProperties": false,
-          "properties": {
-            "joint": {
-              "$ref": "#/properties/recipe/anyOf/0/properties/name"
-            },
-            "keys": {
-              "items": {
-                "additionalProperties": false,
-                "properties": {
-                  "position": {
-                    "default": [
-                      0,
-                      0,
-                      0
-                    ],
-                    "items": [
-                      {
-                        "maximum": 100,
-                        "minimum": -100,
-                        "type": "number"
-                      },
-                      {
-                        "maximum": 100,
-                        "minimum": -100,
-                        "type": "number"
-                      },
-                      {
-                        "maximum": 100,
-                        "minimum": -100,
-                        "type": "number"
-                      }
-                    ],
-                    "maxItems": 3,
-                    "minItems": 3,
-                    "type": "array"
-                  },
-                  "rotation": {
-                    "items": [
-                      {
-                        "maximum": 720,
-                        "minimum": -720,
-                        "type": "number"
-                      },
-                      {
-                        "maximum": 720,
-                        "minimum": -720,
-                        "type": "number"
-                      },
-                      {
-                        "maximum": 720,
-                        "minimum": -720,
-                        "type": "number"
-                      }
-                    ],
-                    "maxItems": 3,
-                    "minItems": 3,
-                    "type": "array"
-                  },
-                  "time": {
-                    "maximum": 30,
-                    "minimum": 0,
-                    "type": "number"
-                  }
-                },
-                "required": [
-                  "time",
-                  "rotation"
-                ],
-                "type": "object"
-              },
-              "maxItems": 128,
-              "minItems": 2,
-              "type": "array"
-            }
-          },
-          "required": [
-            "joint",
-            "keys"
-          ],
-          "type": "object"
-        },
-        "maxItems": 128,
-        "minItems": 1,
-        "type": "array"
-      }
-    },
-    "required": [
-      "kind",
-      "name",
-      "duration",
-      "loop",
-      "tracks"
-    ],
-    "type": "object"
-  },
-  {
-    "additionalProperties": false,
-    "properties": {
-      "beam": {
-        "additionalProperties": false,
-        "description": "Render a straight laser along local -Z instead of particles. Size is width and lifetime is preview duration.",
-        "properties": {
-          "length": {
-            "maximum": 100,
-            "minimum": 0.1,
-            "type": "number"
-          }
-        },
-        "required": [
-          "length"
-        ],
-        "type": "object"
-      },
-      "color": {
-        "items": [
-          {
-            "maximum": 1,
-            "minimum": 0,
-            "type": "number"
-          },
-          {
-            "maximum": 1,
-            "minimum": 0,
-            "type": "number"
-          },
-          {
-            "maximum": 1,
-            "minimum": 0,
-            "type": "number"
-          }
-        ],
-        "maxItems": 3,
-        "minItems": 3,
-        "type": "array"
-      },
-      "count": {
-        "maximum": 500,
-        "minimum": 1,
-        "type": "integer"
-      },
-      "kind": {
-        "const": "vfx",
-        "type": "string"
-      },
-      "lifetime": {
-        "maximum": 10,
-        "minimum": 0.05,
-        "type": "number"
-      },
-      "lightEmission": {
-        "default": 0.7,
-        "maximum": 1,
-        "minimum": 0,
-        "type": "number"
-      },
-      "name": {
-        "$ref": "#/properties/recipe/anyOf/0/properties/name"
-      },
-      "offset": {
-        "default": [
-          0,
-          0,
-          0
-        ],
-        "items": [
-          {
-            "maximum": 20,
-            "minimum": -20,
-            "type": "number"
-          },
-          {
-            "maximum": 20,
-            "minimum": -20,
-            "type": "number"
-          },
-          {
-            "maximum": 20,
-            "minimum": -20,
-            "type": "number"
-          }
-        ],
-        "maxItems": 3,
-        "minItems": 3,
-        "type": "array"
-      },
-      "rate": {
-        "default": 0,
-        "maximum": 200,
-        "minimum": 0,
-        "type": "number"
-      },
-      "size": {
-        "maximum": 10,
-        "minimum": 0.05,
-        "type": "number"
-      },
-      "speed": {
-        "maximum": 50,
-        "minimum": 0,
-        "type": "number"
-      },
-      "spread": {
-        "default": 30,
-        "maximum": 180,
-        "minimum": 0,
-        "type": "number"
-      },
-      "texture": {
-        "pattern": "^rbxassetid:\\/\\/\\d+$",
-        "type": "string"
-      }
-    },
-    "required": [
-      "kind",
-      "name",
-      "color",
-      "size",
-      "lifetime",
-      "speed",
-      "count"
-    ],
-    "type": "object"
-  }
-]New value: +[
+  {
+    "additionalProperties": false,
+    "properties": {
+      "duration": {
+        "maximum": 30,
+        "minimum": 0.1,
+        "type": "number"
+      },
+      "kind": {
+        "const": "animation",
+        "type": "string"
+      },
+      "loop": {
+        "type": "boolean"
+      },
+      "markers": {
+        "default": [],
+        "items": {
+          "additionalProperties": false,
+          "properties": {
+            "name": {
+              "$ref": "#/properties/recipe/anyOf/0/properties/name"
+            },
+            "time": {
+              "maximum": 30,
+              "minimum": 0,
+              "type": "number"
+            }
+          },
+          "required": [
+            "name",
+            "time"
+          ],
+          "type": "object"
+        },
+        "maxItems": 100,
+        "type": "array"
+      },
+      "name": {
+        "maxLength": 80,
+        "minLength": 1,
+        "type": "string"
+      },
+      "tracks": {
+        "items": {
+          "additionalProperties": false,
+          "properties": {
+            "joint": {
+              "$ref": "#/properties/recipe/anyOf/0/properties/name"
+            },
+            "keys": {
+              "items": {
+                "additionalProperties": false,
+                "properties": {
+                  "position": {
+                    "default": [
+                      0,
+                      0,
+                      0
+                    ],
+                    "items": [
+                      {
+                        "maximum": 100,
+                        "minimum": -100,
+                        "type": "number"
+                      },
+                      {
+                        "maximum": 100,
+                        "minimum": -100,
+                        "type": "number"
+                      },
+                      {
+                        "maximum": 100,
+                        "minimum": -100,
+                        "type": "number"
+                      }
+                    ],
+                    "maxItems": 3,
+                    "minItems": 3,
+                    "type": "array"
+                  },
+                  "rotation": {
+                    "items": [
+                      {
+                        "maximum": 720,
+                        "minimum": -720,
+                        "type": "number"
+                      },
+                      {
+                        "maximum": 720,
+                        "minimum": -720,
+                        "type": "number"
+                      },
+                      {
+                        "maximum": 720,
+                        "minimum": -720,
+                        "type": "number"
+                      }
+                    ],
+                    "maxItems": 3,
+                    "minItems": 3,
+                    "type": "array"
+                  },
+                  "time": {
+                    "maximum": 30,
+                    "minimum": 0,
+                    "type": "number"
+                  }
+                },
+                "required": [
+                  "time",
+                  "rotation"
+                ],
+                "type": "object"
+              },
+              "maxItems": 128,
+              "minItems": 2,
+              "type": "array"
+            }
+          },
+          "required": [
+            "joint",
+            "keys"
+          ],
+          "type": "object"
+        },
+        "maxItems": 128,
+        "minItems": 1,
+        "type": "array"
+      }
+    },
+    "required": [
+      "kind",
+      "name",
+      "duration",
+      "loop",
+      "tracks"
+    ],
+    "type": "object"
+  },
+  {
+    "additionalProperties": false,
+    "properties": {
+      "beam": {
+        "additionalProperties": false,
+        "description": "Render a straight laser along local -Z instead of particles. Size is width and lifetime is preview duration.",
+        "properties": {
+          "length": {
+            "maximum": 100,
+            "minimum": 0.1,
+            "type": "number"
+          }
+        },
+        "required": [
+          "length"
+        ],
+        "type": "object"
+      },
+      "color": {
+        "items": [
+          {
+            "maximum": 1,
+            "minimum": 0,
+            "type": "number"
+          },
+          {
+            "maximum": 1,
+            "minimum": 0,
+            "type": "number"
+          },
+          {
+            "maximum": 1,
+            "minimum": 0,
+            "type": "number"
+          }
+        ],
+        "maxItems": 3,
+        "minItems": 3,
+        "type": "array"
+      },
+      "column": {
+        "additionalProperties": false,
+        "description": "Growing 3D energy column along local -Z. Size is diameter; lifetime includes travel, hold, and fade.",
+        "properties": {
+          "fadeTime": {
+            "default": 0.25,
+            "maximum": 2,
+            "minimum": 0.05,
+            "type": "number"
+          },
+          "length": {
+            "maximum": 100,
+            "minimum": 0.1,
+            "type": "number"
+          },
+          "origin": {
+            "default": "attachment",
+            "enum": [
+              "attachment",
+              "hands"
+            ],
+            "type": "string"
+          },
+          "travelTime": {
+            "maximum": 5,
+            "minimum": 0.05,
+            "type": "number"
+          }
+        },
+        "required": [
+          "length",
+          "travelTime"
+        ],
+        "type": "object"
+      },
+      "count": {
+        "maximum": 500,
+        "minimum": 1,
+        "type": "integer"
+      },
+      "kind": {
+        "const": "vfx",
+        "type": "string"
+      },
+      "lifetime": {
+        "maximum": 10,
+        "minimum": 0.05,
+        "type": "number"
+      },
+      "lightEmission": {
+        "default": 0.7,
+        "maximum": 1,
+        "minimum": 0,
+        "type": "number"
+      },
+      "name": {
+        "$ref": "#/properties/recipe/anyOf/0/properties/name"
+      },
+      "offset": {
+        "default": [
+          0,
+          0,
+          0
+        ],
+        "items": [
+          {
+            "maximum": 20,
+            "minimum": -20,
+            "type": "number"
+          },
+          {
+            "maximum": 20,
+            "minimum": -20,
+            "type": "number"
+          },
+          {
+            "maximum": 20,
+            "minimum": -20,
+            "type": "number"
+          }
+        ],
+        "maxItems": 3,
+        "minItems": 3,
+        "type": "array"
+      },
+      "rate": {
+        "default": 0,
+        "maximum": 200,
+        "minimum": 0,
+        "type": "number"
+      },
+      "size": {
+        "maximum": 10,
+        "minimum": 0.05,
+        "type": "number"
+      },
+      "speed": {
+        "maximum": 50,
+        "minimum": 0,
+        "type": "number"
+      },
+      "spread": {
+        "default": 30,
+        "maximum": 180,
+        "minimum": 0,
+        "type": "number"
+      },
+      "texture": {
+        "pattern": "^rbxassetid:\\/\\/\\d+$",
+        "type": "string"
+      }
+    },
+    "required": [
+      "kind",
+      "name",
+      "color",
+      "size",
+      "lifetime",
+      "speed",
+      "count"
+    ],
+    "type": "object"
+  }
+]

First observedv0.1.0Sep 7, 2026

TDQS

B3.1/5.0

Behavior3/5

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

Annotations already declare readOnlyHint=false, destructiveHint=false and idempotentHint=false, so the mutation/safety profile is covered structurally. The description adds that the recipe is validated before persisting and mentions revision lineage, which is useful context, but does not explain validation failures, overwrite behavior, or what save does to an existing name.

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?

Three tight sentences with the primary action front-loaded, then the parentId condition, then the unit conventions. Little waste, though the unit notes are terse fragments rather than fully structured.

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

Completeness2/5

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

An output schema exists so return values need not be described, but for a tool with a large two-variant recipe schema the description is thin: it never distinguishes the animation vs vfx shapes, explains required fields, or notes constraints like track/key limits, leaving an agent under-informed about what a valid recipe looks like.

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

Parameters2/5

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

Schema description coverage is 0%, so the description carries the burden. It does add real meaning for parentId (revision lineage) and for the units of position, rotation, and key time, but the bulk of the large nested recipe schema (kind discriminator between animation/vfx, name, markers, loop, duration, and the vfx fields) remains undocumented.

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

Purpose4/5

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

States specific verbs (validate and save) and the resource (custom/revised recipe), which is clearly distinct from read-only siblings like motion_library_list and motion_library_read. However, it does not differentiate itself from motion_animation_create or motion_vfx_create, which also create recipes, leaving some sibling ambiguity.

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?

Gives one concrete usage rule ('Supply parentId to preserve revision lineage'), which is helpful for the revision case. But it offers no guidance on when to choose this tool over motion_animation_create/motion_vfx_create or motion_studio_save_animation, so the routing decision is left to inference.

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