auto-git:

[add] src/geometry/model-instance-collider-generation.ts
 [add] src/runtime-three/rapier-collision-world.ts
 [change] AGENTS.md
 [change] CHAT_CONTEXT.md
 [change] architecture.md
 [change] package.json
 [change] prompts-lite.txt
 [change] prompts.txt
 [change] roadmap.md
 [change] src/assets/model-instances.ts
 [change] src/document/migrate-scene-document.ts
 [change] src/document/scene-document-validation.ts
 [change] src/document/scene-document.ts
 [change] src/runtime-three/first-person-navigation-controller.ts
 [change] src/runtime-three/navigation-controller.ts
 [change] src/runtime-three/runtime-host.ts
 [change] src/runtime-three/runtime-scene-build.ts
 [change] src/runtime-three/runtime-scene-validation.ts
 [change] src/viewport-three/viewport-host.ts
 [change] testing.md

src/document/scene-document-validation.ts

@@ -6,6 +6,7 @@ import {
   type ProjectAssetRecord
 } from "../assets/project-assets";
 import type { ModelInstance } from "../assets/model-instances";
+import { isModelInstanceCollisionMode } from "../assets/model-instances";
 import {
   type InteractableEntity,
   type PointLightEntity,
@@ -646,6 +647,28 @@ function validateModelInstance(modelInstance: ModelInstance, path: string, docum
     diagnostics.push(createDiagnostic("error", "invalid-model-instance-scale", "Model instance scales must remain finite and positive on every axis.", `${path}.scale`));
   }
 
+  if (!isModelInstanceCollisionMode(modelInstance.collision.mode)) {
+    diagnostics.push(
+      createDiagnostic(
+        "error",
+        "invalid-model-instance-collision-mode",
+        "Model instance collision mode must be one of none, terrain, static, dynamic, or simple.",
+        `${path}.collision.mode`
+      )
+    );
+  }
+
+  if (!isBoolean(modelInstance.collision.visible)) {
+    diagnostics.push(
+      createDiagnostic(
+        "error",
+        "invalid-model-instance-collision-visibility",
+        "Model instance collision visibility must be a boolean.",
+        `${path}.collision.visible`
+      )
+    );
+  }
+
   const asset = document.assets[modelInstance.assetId];
 
   if (asset === undefined) {