R3

Change a property LIVE in the user's open R3 editor

r3_editor_set

Destructive

The same tool as r3_component_set (this is its older name): change properties of a component, kept at once in the project's live copy: every R3 tab with the project open shows it now, no editor needed and nothing to save.

Name the component with componentId or entityRef. values take r3_component_set's shapes: a plain value {"roughness": 0.25}; a value component as an object of the keys to change {"position": {"y": 2}} (an EMPTY slot, e.g. a rigid body's centerOfMass, is made from the fields given: {"centerOfMass": {"z": -0.3, "mass": 8}}); a reference as the target's entityRef {"material": "material_cube_1"} (null clears it); a list of references as an array of entityRefs (it REPLACES the list). All-or-nothing: an unknown name is refused with the valid ones. A Code component's code is r3_editor_code's.

Input Schema

Name	Required	Description
`values`	Yes	What to set: {"visible": false, "position": {"y": 2}, "material": "material_cube_1"}.
`entityRef`	No	Or its entityRef, e.g. "mesh_cube_1".
`projectId`	Yes	The project (r3_project_list).
`componentId`	No	The component's id (r3_project_load / r3_editor_inspect).

Output Schema

Name	Required	Description
`seq`	No
`live`	Yes
`type`	Yes
`saved`	Yes
`answer`	Yes	This answer in words: what was done, what R3 measured, decided or refused, and what to do next. The same text as the result's text block. Read it: the fields beside it are the data, this is the guidance.
`editor`	Yes
`landed`	Yes
`changes`	Yes
`entityRef`	Yes
`projectId`	Yes
`componentId`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed1 schema field changedOct 19, 2026

changedOutput schema / properties / editor / anyOf

Previous value: -[
-  {
-    "additionalProperties": false,
-    "properties": {
-      "lastActiveAgoMs": {
-        "type": "number"
-      },
-      "lastActiveAt": {
-        "type": "string"
-      },
-      "openProjects": {
-        "anyOf": [
-          {
-            "items": {
-              "additionalProperties": false,
-              "properties": {
-                "id": {
-                  "type": "string"
-                },
-                "name": {
-                  "type": [
-                    "string",
-                    "null"
-                  ]
-                }
-              },
-              "required": [
-                "id",
-                "name"
-              ],
-              "type": "object"
-            },
-            "type": "array"
-          },
-          {
-            "type": "null"
-          }
-        ]
-      },
-      "openedAt": {
-        "type": [
-          "string",
-          "null"
-        ]
-      }
-    },
-    "required": [
-      "openedAt",
-      "lastActiveAt",
-      "lastActiveAgoMs",
-      "openProjects"
-    ],
-    "type": "object"
-  },
-  {
-    "type": "null"
-  }
-]New value: +[
+  {
+    "additionalProperties": false,
+    "properties": {
+      "frames": {
+        "anyOf": [
+          {
+            "additionalProperties": false,
+            "properties": {
+              "advancing": {
+                "type": "boolean"
+              },
+              "frameSeen": {
+                "type": "boolean"
+              },
+              "sceneShown": {
+                "type": "boolean"
+              },
+              "visible": {
+                "type": "boolean"
+              }
+            },
+            "required": [
+              "advancing",
+              "visible",
+              "sceneShown",
+              "frameSeen"
+            ],
+            "type": "object"
+          },
+          {
+            "type": "null"
+          }
+        ]
+      },
+      "lastActiveAgoMs": {
+        "type": "number"
+      },
+      "lastActiveAt": {
+        "type": "string"
+      },
+      "openProjects": {
+        "anyOf": [
+          {
+            "items": {
+              "additionalProperties": false,
+              "properties": {
+                "id": {
+                  "type": "string"
+                },
+                "name": {
+                  "type": [
+                    "string",
+                    "null"
+                  ]
+                }
+              },
+              "required": [
+                "id",
+                "name"
+              ],
+              "type": "object"
+            },
+            "type": "array"
+          },
+          {
+            "type": "null"
+          }
+        ]
+      },
+      "openedAt": {
+        "type": [
+          "string",
+          "null"
+        ]
+      }
+    },
+    "required": [
+      "openedAt",
+      "lastActiveAt",
+      "lastActiveAgoMs",
+      "openProjects"
+    ],
+    "type": "object"
+  },
+  {
+    "type": "null"
+  }
+]

Changed2 schema fields changedOct 15, 2026

addedOutput schema / properties / answer

Added value: +{
+  "description": "This answer in words: what was done, what R3 measured, decided or refused, and what to do next. The same text as the result's text block. Read it: the fields beside it are the data, this is the guidance.",
+  "type": "string"
+}

changedOutput schema / required

Previous value: -[
-  "projectId",
-  "componentId",
-  "entityRef",
-  "type",
-  "changes",
-  "landed",
-  "live",
-  "saved",
-  "editor"
-]New value: +[
+  "projectId",
+  "componentId",
+  "entityRef",
+  "type",
+  "changes",
+  "landed",
+  "live",
+  "saved",
+  "editor",
+  "answer"
+]

First observedOct 15, 2026

TDQS

A4.4/5.0

Behavior4/5

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

Annotations already flag destructive=true, idempotent=false and openWorld=true, so the safety profile is covered. The description adds real behavioral context beyond that: all-or-nothing application, unknown names refused with the valid ones returned, live propagation across tabs, and the null-clears / list-replaces semantics.

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?

Front-loads the identity and live-propagation point, then spends the rest on parameter shape detail, which is dense and mostly earns its place. The opening parenthetical about the older name is slightly redundant but sets up the sibling relationship.

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

Completeness4/5

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

For a destructive mutation with an output schema present and full annotation coverage, the description supplies the missing pieces: atomicity, null/list semantics, and code-change routing. It stops short of noting permission or session prerequisites, but the agent otherwise has enough to call it correctly.

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

Parameters5/5

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

Although schema coverage is 100%, the description goes well past the schema's thin 'What to set' note by enumerating every accepted values shape: plain value, value-component object, empty-slot construction, entityRef reference, null to clear, and array-of-refs which replaces the list. It also clarifies that componentId and entityRef are interchangeable identifiers.

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?

States a specific verb and resource (change component properties) and pinpoints scope: the project's live copy, reflected in every open R3 tab. It also explicitly disambiguates from siblings, noting it is the older name for r3_component_set and deferring code changes to r3_editor_code.

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

Usage Guidelines4/5

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

Gives clear operating context ('live', 'no editor needed, nothing to save') and routes one case to an alternative, telling the agent that a Code component's code belongs to r3_editor_code. It does not, however, explain when to prefer this over its alias r3_component_set, which is a notable gap given it declares them identical.

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

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