Merge remote-tracking branch 'origin/main' into ochafik/readme-mcp-config

examples/threejs-server/README.md

@@ -129,3 +129,31 @@ React component that:
 - Displays streaming preview from `toolInputsPartial.code` as code arrives
 - Executes final code from `toolInputs.code` when complete
 - Renders to a pre-created canvas with configurable height
+
+## Performance
+
+### Visibility-Based Pause
+
+Animation automatically pauses when the widget scrolls out of view:
+
+- Uses `IntersectionObserver` to track visibility (browser-native, no polling)
+- Wraps `requestAnimationFrame` to skip frames when not visible
+- Animation loop stops completely → zero CPU usage while hidden
+- Queued callbacks resume instantly when scrolled back into view
+
+This is transparent to user code - just use `requestAnimationFrame` normally.
+
+### Transparent Background
+
+Supports alpha transparency for seamless host UI integration:
+
+```javascript
+const renderer = new THREE.WebGLRenderer({
+  canvas,
+  antialias: true,
+  alpha: true,
+});
+renderer.setClearColor(0x000000, 0); // Fully transparent
+```
+
+This is the default - 3D objects composite directly over the host background.