Roblox MCP

by hope1026

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manage_tween

Create, play, pause, or cancel tweens to animate properties of instances in Roblox Studio.

Instructions

[PRO] Tween service: create, play, pause, cancel tweens for smooth animations.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "action": "<action>"
    },
    "name": "manage_tween"
  }
}

Input Schema

Name	Required	Description
`action`	Yes	[PRO] Tween action. create: create a new tween with target properties. play: play a created tween. pause: pause a running tween. cancel: cancel a tween.
`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.
`path`	No	Instance path to tween. Used by: create (required).
`tweenInfo`	No	Tween configuration. Used by: create.
`properties`	No	Target property values to tween to. Used by: create. Supports Vector3, Color3, numbers, etc.
`tweenId`	No	Tween identifier returned by create. Used by: play, pause, cancel.

Schema Changelog

Changes observed during successful MCP inspections.

Changed3 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"
+}

First observedv2.0.1Mar 24, 2026

TDQS

B3.1/5.0

Behavior2/5

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

With no annotations, the description should disclose behavioral traits like destructiveness, permission requirements, or side effects. It only says 'smooth animations' and lists actions, missing critical context for an AI agent.

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 a single, front-loaded sentence. It is concise but could be more informative without becoming verbose.

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?

Given 8 parameters, nested objects, and no output schema, the description fails to explain return values (e.g., tweenId from create) or provide sufficient behavioral context for a complex tool.

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 parameters are fully documented there. The description adds little beyond summarizing actions, meeting the baseline.

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 verb 'manage tween service' and enumerates the specific actions (create, play, pause, cancel). It distinguishes this tool from siblings like manage_animation by focusing on tweens.

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

Usage Guidelines2/5

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

No guidance on when to use this tool versus alternatives such as manage_animation or manage_effects. No mention of prerequisites, typical use cases, or when not to use it.

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