R3

Take a picture of the project in the user's open R3 editor

r3_editor_capture

Read-only

Capture the canvas of a project open in the user's R3 editor — the scene as it looks NOW, running physics included — and LOOK at it: the answer is an image. Call it after a visual change (r3_editor_set, r3_editor_create, r3_editor_code …) to check what you built, and after r3_editor_run to see it move. By default (camera: "editor") it is what the user sees: the editor's view camera, edit aids included. camera: "project" takes it through the project's own camera instead, with no edit aids, as a visitor sees it: use that to check a camera or a camera script. At most 1280 px each way (width, default 1024); a JPEG. Needs project:read.

Input Schema

Name	Required	Description
`width`	No	The picture's largest width in px, 64..1280 (default 1024); it keeps the canvas's aspect and is never scaled up.
`camera`	No	Whose view: "editor" (default) = the editor's view camera the user looks through, edit aids included; "project" = the project's own camera, no edit aids, as a visitor sees it (check a camera script with it).
`projectId`	Yes	A project open in the user's editor (r3_whoami lists them).

Output Schema

Name	Required	Description
`bytes`	Yes
`width`	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.
`camera`	Yes
`editor`	Yes
`height`	Yes
`mimeType`	Yes
`projectId`	Yes

Schema Changelog

Changes observed during successful MCP inspections.

Changed3 schema fields changedOct 20, 2026

addedInput schema / properties / camera

Added value: +{
+  "description": "Whose view: \"editor\" (default) = the editor's view camera the user looks through, edit aids included; \"project\" = the project's own camera, no edit aids, as a visitor sees it (check a camera script with it).",
+  "enum": [
+    "editor",
+    "project"
+  ],
+  "type": "string"
+}

addedOutput schema / properties / camera

Added value: +{
+  "enum": [
+    "editor",
+    "project"
+  ],
+  "type": "string"
+}

changedOutput schema / required

Previous value: -[
-  "projectId",
-  "width",
-  "height",
-  "mimeType",
-  "bytes",
-  "editor",
-  "answer"
-]New value: +[
+  "projectId",
+  "camera",
+  "width",
+  "height",
+  "mimeType",
+  "bytes",
+  "editor",
+  "answer"
+]

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",
-  "width",
-  "height",
-  "mimeType",
-  "bytes",
-  "editor"
-]New value: +[
+  "projectId",
+  "width",
+  "height",
+  "mimeType",
+  "bytes",
+  "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?

Annotations only declare readOnlyHint and openWorldHint; the description goes well beyond by disclosing the return type (an image, JPEG), the resolution ceiling (1280 px each way), the default camera semantics, and the project:read permission requirement. That is exactly the kind of context annotations cannot convey.

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 action and outcome, then branches into usage and camera modes. Dense and mostly waste-free, though the parenthetical asides and repeated camera explanations make it longer than strictly necessary.

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?

With an output schema present, the description need not explain return values, yet it still signals that the answer is an image. Auth needs, default resolution, camera modes, and sequencing with sibling editor tools are all covered, so nothing needed to call it 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 practical meaning: the default behavior of camera:'editor' (user's view, edit aids included) versus 'project' (visitor's view, no edit aids) and the output format/size implications of width. It slightly exceeds what the schema alone conveys.

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 (capture) and resource (the canvas of a project open in the user's R3 editor) with a clear qualifier ('the scene as it looks NOW, running physics included'). It distinguishes itself from siblings like r3_image_create or r3_preview_create by scoping to the live editor viewport.

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?

Explicitly names the trigger conditions and the sibling tools that precede it: call after a visual change (r3_editor_set, r3_editor_create, r3_editor_code) and after r3_editor_run to see motion. It also gives a targeted use case for the camera:'project' variant (checking a camera or camera script), leaving little to inference.

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

All R3 tools Inspect

Try in Browser

Shareable, User-Owned Context BackendPeople, applications, and agents read, write, and coordinate together in one context lake. Reach it over MCP, a CLI, a Python SDK, or REST.fulcradynamics.comAd

Glama MCP Gateway

Add one secure layer between your agents and this server.

Resources

Need Help?