R3

Read live component values from the user's open R3 editor

r3_editor_inspect

Read-only

Read what components hold RIGHT NOW in an R3 tab that has the project open: runtime values included — a moving body's position while the project runs. Use it to debug live behaviour. It needs a tab with the project open (r3_editor_open opens one). r3_component_read reads the kept values without a tab.

Select with any of: ids (component ids from r3_project_load), type ("Mesh", "RigidBodyDynamic", …) and entityRef; they combine. fields keeps only the properties you name (e.g. ["position", "rotation"]). At most 50 components per call; a larger answer is refused with how to narrow it.

Values are in r3_component_read's shape (value components inline, references as entityRefs), so they can be handed to r3_component_set. The project must be open in the editor (r3_editor_open opens it). Read-only: nothing is changed.

Input Schema

Name	Required	Description
`ids`	No	Component ids to read.
`type`	No	Only components of this type, e.g. "Mesh" or "R3ComponentMesh".
`fields`	No	Only these properties, e.g. ["position", "rotation"].
`entityRef`	No	Only the component with this entityRef.
`projectId`	Yes	The project, open in the user's editor.

Output Schema

Name	Required	Description
`live`	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
`projectId`	Yes
`components`	Yes
`unreadable`	Yes
`projectName`	Yes
`fieldsNotFound`	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"
+  }
+]

Changed1 schema field changedOct 16, 2026
- addedOutput schema / properties / components / items / properties / eventName
```
Added value: +{
+  "type": "string"
+}
```

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",
-  "projectName",
-  "live",
-  "components",
-  "unreadable",
-  "fieldsNotFound",
-  "editor"
-]New value: +[
+  "projectId",
+  "projectName",
+  "live",
+  "components",
+  "unreadable",
+  "fieldsNotFound",
+  "editor",
+  "answer"
+]

First observedOct 15, 2026

TDQS

A4.8/5.0

Behavior5/5

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

Beyond the annotations, it discloses that runtime values are included (a moving body's position while the project runs), that a limit of 50 components per call exists and larger answers are refused with narrowing guidance, and that output shape matches r3_component_read so results can feed r3_component_set. readOnlyHint/destructiveHint are reinforced by 'Read-only: nothing is changed', and the changing live values are consistent with idempotentHint=false.

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-loaded with the core purpose and the live-value distinction, then parameters then constraints. Slightly redundant: the 'project must be open in the editor (r3_editor_open opens it)' requirement is stated twice, once early and once at the end.

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

Completeness5/5

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, and the description still flags the output shape and its compatibility with r3_component_set. Prerequisite, limits, filtering semantics, and read-only nature are all covered — nothing an agent needs to call this correctly is missing.

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

Parameters4/5

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

Schema coverage is 100%, so the baseline is 3, but the description adds semantics the schema does not encode — that ids, type, and entityRef 'combine' (conjunctive filtering) and that fields keeps only the named properties. Examples for fields and type types align with the schema rather than duplicating it verbatim.

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 precise verb+resource+scope: reading live/runtime component values from a project open in an R3 editor tab. It explicitly contrasts with the nearest siblings, r3_component_read ('kept values without a tab') and r3_editor_open (opens the tab), so an agent can route without opening schemas.

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

Usage Guidelines5/5

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

Gives the when ('use it to debug live behaviour'), the prerequisite ('needs a tab with the project open'), the tool that satisfies that prerequisite, and the alternative (r3_component_read) with the condition that selects it. Nothing 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.

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