diff --git a/packages/cli/src/commands/render.test.ts b/packages/cli/src/commands/render.test.ts
index b74860fb3..a97ad3669 100644
--- a/packages/cli/src/commands/render.test.ts
+++ b/packages/cli/src/commands/render.test.ts
@@ -165,7 +165,7 @@ describe("renderLocal browser GPU config", () => {
       quality: "standard",
       format: "mp4",
       gpu: false,
-      browserGpu: false,
+      browserGpuMode: "software",
       hdrMode: "auto",
       quiet: true,
       entryFile: "compositions/intro.html",
@@ -181,7 +181,7 @@ describe("renderLocal browser GPU config", () => {
       quality: "standard",
       format: "mp4",
       gpu: false,
-      browserGpu: false,
+      browserGpuMode: "software",
       hdrMode: "auto",
       quiet: true,
     });
diff --git a/packages/core/src/runtime/adapters/animejs.ts b/packages/core/src/runtime/adapters/animejs.ts
index 759f281a9..5e4986ad2 100644
--- a/packages/core/src/runtime/adapters/animejs.ts
+++ b/packages/core/src/runtime/adapters/animejs.ts
@@ -1,4 +1,5 @@
 import type { RuntimeDeterministicAdapter } from "../types";
+import { swallow } from "../diagnostics";
 
 /**
  * anime.js adapter for HyperFrames
@@ -61,8 +62,9 @@ export function createAnimeJsAdapter(): RuntimeDeterministicAdapter {
           }
         }
         (window as AnimeWindow).__hfAnime = existing;
-      } catch {
+      } catch (err) {
         // ignore discovery failures
+        swallow("runtime.adapters.animejs.site1", err);
       }
     },
 
@@ -76,8 +78,9 @@ export function createAnimeJsAdapter(): RuntimeDeterministicAdapter {
           if (typeof instance.seek === "function") {
             instance.seek(timeMs);
           }
-        } catch {
+        } catch (err) {
           // ignore per-instance failures — keep going for other instances
+          swallow("runtime.adapters.animejs.site2", err);
         }
       }
     },
@@ -91,8 +94,9 @@ export function createAnimeJsAdapter(): RuntimeDeterministicAdapter {
           if (typeof instance.pause === "function") {
             instance.pause();
           }
-        } catch {
+        } catch (err) {
           // ignore
+          swallow("runtime.adapters.animejs.site3", err);
         }
       }
     },
@@ -106,8 +110,9 @@ export function createAnimeJsAdapter(): RuntimeDeterministicAdapter {
           if (typeof instance.play === "function") {
             instance.play();
           }
-        } catch {
+        } catch (err) {
           // ignore
+          swallow("runtime.adapters.animejs.site4", err);
         }
       }
     },
diff --git a/packages/core/src/runtime/adapters/css.ts b/packages/core/src/runtime/adapters/css.ts
index 8c2ff6904..0649c1473 100644
--- a/packages/core/src/runtime/adapters/css.ts
+++ b/packages/core/src/runtime/adapters/css.ts
@@ -1,4 +1,5 @@
 import type { RuntimeDeterministicAdapter } from "../types";
+import { swallow } from "../diagnostics";
 
 export function createCssAdapter(params?: {
   resolveStartSeconds?: (element: Element) => number;
@@ -22,13 +23,15 @@ export function createCssAdapter(params?: {
     for (const animation of animations) {
       try {
         animation.currentTime = timeMs;
-      } catch {
+      } catch (err) {
         // ignore animations that reject currentTime writes
+        swallow("runtime.adapters.css.site1", err);
       }
       try {
         animation.pause();
-      } catch {
+      } catch (err) {
         // infinite unresolved animations can throw on pause before currentTime sticks
+        swallow("runtime.adapters.css.site2", err);
       }
     }
   };
@@ -37,8 +40,9 @@ export function createCssAdapter(params?: {
     for (const animation of animations) {
       try {
         animation.play();
-      } catch {
+      } catch (err) {
         // ignore animation edge-cases
+        swallow("runtime.adapters.css.site3", err);
       }
     }
   };
@@ -47,8 +51,9 @@ export function createCssAdapter(params?: {
     for (const animation of animations) {
       try {
         animation.pause();
-      } catch {
+      } catch (err) {
         // ignore animation edge-cases
+        swallow("runtime.adapters.css.site4", err);
       }
     }
   };
diff --git a/packages/core/src/runtime/adapters/lottie.ts b/packages/core/src/runtime/adapters/lottie.ts
index 5b7f6aa4c..74da88a16 100644
--- a/packages/core/src/runtime/adapters/lottie.ts
+++ b/packages/core/src/runtime/adapters/lottie.ts
@@ -1,4 +1,5 @@
 import type { RuntimeDeterministicAdapter } from "../types";
+import { swallow } from "../diagnostics";
 export { isLottieAnimationLoaded } from "./lottieReadiness";
 
 /**
@@ -71,8 +72,9 @@ export function createLottieAdapter(): RuntimeDeterministicAdapter {
             (window as LottieWindow).__hfLottie = existing;
           }
         }
-      } catch {
+      } catch (err) {
         // ignore discovery failures
+        swallow("runtime.adapters.lottie.site1", err);
       }
     },
 
@@ -107,8 +109,9 @@ export function createLottieAdapter(): RuntimeDeterministicAdapter {
               anim.seek(percentage);
             }
           }
-        } catch {
+        } catch (err) {
           // ignore per-animation failures — keep going for other instances
+          swallow("runtime.adapters.lottie.site2", err);
         }
       }
     },
@@ -124,8 +127,9 @@ export function createLottieAdapter(): RuntimeDeterministicAdapter {
           } else if (isDotLottiePlayer(anim)) {
             anim.pause();
           }
-        } catch {
+        } catch (err) {
           // ignore
+          swallow("runtime.adapters.lottie.site3", err);
         }
       }
     },
diff --git a/packages/core/src/runtime/adapters/three.ts b/packages/core/src/runtime/adapters/three.ts
index 49704e50c..600749a71 100644
--- a/packages/core/src/runtime/adapters/three.ts
+++ b/packages/core/src/runtime/adapters/three.ts
@@ -1,4 +1,5 @@
 import type { RuntimeDeterministicAdapter } from "../types";
+import { swallow } from "../diagnostics";
 
 export function createThreeAdapter(): RuntimeDeterministicAdapter {
   let forcedTime: number | null = null;
@@ -13,8 +14,9 @@ export function createThreeAdapter(): RuntimeDeterministicAdapter {
       window.__hfThreeTime = forcedTime;
       try {
         window.dispatchEvent(new CustomEvent("hf-seek", { detail: { time: forcedTime } }));
-      } catch {
+      } catch (err) {
         // ignore custom event failures
+        swallow("runtime.adapters.three.site1", err);
       }
     },
     pause: () => {
diff --git a/packages/core/src/runtime/adapters/waapi.ts b/packages/core/src/runtime/adapters/waapi.ts
index 4421d3fb3..64ea6b03b 100644
--- a/packages/core/src/runtime/adapters/waapi.ts
+++ b/packages/core/src/runtime/adapters/waapi.ts
@@ -1,4 +1,5 @@
 import type { RuntimeDeterministicAdapter } from "../types";
+import { swallow } from "../diagnostics";
 
 export function createWaapiAdapter(): RuntimeDeterministicAdapter {
   return {
@@ -10,13 +11,15 @@ export function createWaapiAdapter(): RuntimeDeterministicAdapter {
       for (const animation of document.getAnimations()) {
         try {
           animation.currentTime = timeMs;
-        } catch {
+        } catch (err) {
           // ignore animations that reject currentTime writes
+          swallow("runtime.adapters.waapi.site1", err);
         }
         try {
           animation.pause();
-        } catch {
+        } catch (err) {
           // infinite unresolved animations can throw here until currentTime resolves
+          swallow("runtime.adapters.waapi.site2", err);
         }
       }
     },
@@ -25,8 +28,9 @@ export function createWaapiAdapter(): RuntimeDeterministicAdapter {
       for (const animation of document.getAnimations()) {
         try {
           animation.pause();
-        } catch {
+        } catch (err) {
           // ignore animation edge-cases
+          swallow("runtime.adapters.waapi.site3", err);
         }
       }
     },
diff --git a/packages/core/src/runtime/analytics.ts b/packages/core/src/runtime/analytics.ts
index 845970157..7746823fb 100644
--- a/packages/core/src/runtime/analytics.ts
+++ b/packages/core/src/runtime/analytics.ts
@@ -1,3 +1,4 @@
+import { swallow } from "./diagnostics";
 /**
  * Runtime analytics & performance telemetry — vendor-agnostic event emission.
  *
@@ -75,8 +76,9 @@ export function emitAnalyticsEvent(
       event,
       properties: properties ?? {},
     });
-  } catch {
+  } catch (err) {
     // Never let analytics failures affect the runtime
+    swallow("runtime.analytics.site1", err);
   }
 }
 
@@ -107,8 +109,9 @@ export function emitPerformanceMetric(
     if (typeof performance !== "undefined" && typeof performance.mark === "function") {
       performance.mark(name, { detail: { value, tags: tags ?? {} } });
     }
-  } catch {
+  } catch (err) {
     // performance API unavailable or rejected — keep going
+    swallow("runtime.analytics.site2", err);
   }
 
   if (!_postMessage) return;
@@ -120,7 +123,8 @@ export function emitPerformanceMetric(
       value,
       tags: tags ?? {},
     });
-  } catch {
+  } catch (err) {
     // Never let telemetry failures affect the runtime
+    swallow("runtime.analytics.site3", err);
   }
 }
diff --git a/packages/core/src/runtime/bridge.ts b/packages/core/src/runtime/bridge.ts
index 73fcdbd4b..d6f95ef18 100644
--- a/packages/core/src/runtime/bridge.ts
+++ b/packages/core/src/runtime/bridge.ts
@@ -1,3 +1,4 @@
+import { swallow } from "./diagnostics";
 import type { RuntimeBridgeControlMessage, RuntimeOutboundMessage } from "./types";
 
 type BridgeDeps = {
@@ -15,8 +16,9 @@ type BridgeDeps = {
 export function postRuntimeMessage(payload: RuntimeOutboundMessage): void {
   try {
     window.parent.postMessage(payload, "*");
-  } catch {
-    // Ignore cross-frame posting failures.
+  } catch (err) {
+    // Cross-frame posting can throw if the parent is gone or origin-isolated.
+    swallow("bridge.postMessage", err);
   }
 }
 
@@ -104,8 +106,9 @@ function flashElements(selectors: string[], duration: number): void {
         el.classList.add("__hf-flash");
         setTimeout(() => el.classList.remove("__hf-flash"), duration);
       });
-    } catch {
+    } catch (err) {
       // Invalid selector — skip
+      swallow("bridge.flashElements.querySelector", err);
     }
   }
 }
diff --git a/packages/core/src/runtime/diagnostics.test.ts b/packages/core/src/runtime/diagnostics.test.ts
new file mode 100644
index 000000000..66024712b
--- /dev/null
+++ b/packages/core/src/runtime/diagnostics.test.ts
@@ -0,0 +1,77 @@
+// @vitest-environment happy-dom
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+import { swallow } from "./diagnostics";
+
+interface HFTestWindow {
+  __hfDebug?: boolean;
+  __HYPERFRAMES_DEBUG?: boolean;
+  __hf?: {
+    onSwallowed?: (e: { label: string; error: unknown }) => void;
+  };
+}
+
+describe("swallow", () => {
+  const w = window as unknown as HFTestWindow;
+  const originalDebug = console.debug;
+
+  beforeEach(() => {
+    delete w.__hfDebug;
+    delete w.__HYPERFRAMES_DEBUG;
+    delete w.__hf;
+    console.debug = vi.fn();
+  });
+
+  afterEach(() => {
+    console.debug = originalDebug;
+    delete w.__hfDebug;
+    delete w.__HYPERFRAMES_DEBUG;
+    delete w.__hf;
+  });
+
+  it("is silent by default — no console output, no handler call", () => {
+    swallow("test.silent", new Error("boom"));
+    expect(console.debug).not.toHaveBeenCalled();
+  });
+
+  it("logs to console.debug when window.__hfDebug is true", () => {
+    w.__hfDebug = true;
+    const err = new Error("boom");
+    swallow("test.debug", err);
+    expect(console.debug).toHaveBeenCalledWith("[hyperframes] test.debug swallowed:", err);
+  });
+
+  it("also honors window.__HYPERFRAMES_DEBUG (legacy flag)", () => {
+    w.__HYPERFRAMES_DEBUG = true;
+    swallow("test.legacy", "string-error");
+    expect(console.debug).toHaveBeenCalledWith(
+      "[hyperframes] test.legacy swallowed:",
+      "string-error",
+    );
+  });
+
+  it("dispatches to window.__hf.onSwallowed when installed", () => {
+    const handler = vi.fn();
+    w.__hf = { onSwallowed: handler };
+    const err = new Error("from handler");
+    swallow("test.handler", err);
+    expect(handler).toHaveBeenCalledWith({ label: "test.handler", error: err });
+  });
+
+  it("does not propagate errors from the user-installed handler", () => {
+    w.__hf = {
+      onSwallowed: () => {
+        throw new Error("handler exploded");
+      },
+    };
+    expect(() => swallow("test.handler-throws", new Error("real"))).not.toThrow();
+  });
+
+  it("can run with both handler AND debug flag set", () => {
+    w.__hfDebug = true;
+    const handler = vi.fn();
+    w.__hf = { onSwallowed: handler };
+    swallow("test.both", "err");
+    expect(handler).toHaveBeenCalled();
+    expect(console.debug).toHaveBeenCalled();
+  });
+});
diff --git a/packages/core/src/runtime/diagnostics.ts b/packages/core/src/runtime/diagnostics.ts
new file mode 100644
index 000000000..7aac85a16
--- /dev/null
+++ b/packages/core/src/runtime/diagnostics.ts
@@ -0,0 +1,66 @@
+/**
+ * Runtime diagnostic helpers for best-effort operations.
+ *
+ * Many runtime operations (postMessage to a parent frame, `media.play()` /
+ * `pause()` / `currentTime=`, timeline `seek()`, anime.js feature detection,
+ * etc.) can throw under perfectly normal conditions: the parent frame is
+ * cross-origin, autoplay is denied, the media element was just removed from
+ * the DOM, the timeline has been disposed, the host page does not include
+ * anime.js. The right behaviour in each case is "tried, didn't work, move
+ * on" — but emitting nothing makes silent failures invisible to anyone
+ * debugging a genuinely broken composition, and the bare `catch {}` shape
+ * also trips strict lint configurations on the inlined runtime IIFE.
+ *
+ * `swallow(label, err)` is the single funnel for these intentional silences.
+ * It dispatches to:
+ *
+ *   - `console.debug` with the label, the error, and a `[hyperframes]` prefix
+ *     when `window.__hfDebug === true` (or the legacy `__HYPERFRAMES_DEBUG`
+ *     env-style global). Quiet by default; flip the flag in DevTools when
+ *     hunting a regression.
+ *   - A custom `__hf.onSwallowed` handler if installed — lets the studio /
+ *     embeddings collect runtime swallow events without polluting the page
+ *     console.
+ *
+ * Production behaviour without either flag set: completely silent, just
+ * like the original empty `catch {}`. The shape is also lint-clean — the
+ * helper call is a real statement, so no `no-empty` warnings ship in the
+ * inlined IIFE.
+ */
+export interface SwallowedEvent {
+  /** Short, descriptive label naming the operation that failed. */
+  label: string;
+  /** The thrown value (often an Error, but JS allows anything). */
+  error: unknown;
+}
+
+interface HFDebugSurface {
+  __hfDebug?: boolean;
+  __HYPERFRAMES_DEBUG?: boolean;
+  __hf?: {
+    onSwallowed?: (event: SwallowedEvent) => void;
+  };
+}
+
+export function swallow(label: string, error?: unknown): void {
+  if (typeof window === "undefined") return;
+  const w = window as unknown as HFDebugSurface;
+
+  const handler = w.__hf?.onSwallowed;
+  if (handler) {
+    try {
+      handler({ label, error });
+    } catch (handlerError) {
+      // Don't recurse into swallow() — a consumer hook that throws
+      // shouldn't be allowed to take down the runtime, and routing the
+      // failure back through swallow() would loop. Drop on the floor;
+      // the original error already had its surface above.
+      void handlerError;
+    }
+  }
+
+  if (w.__hfDebug || w.__HYPERFRAMES_DEBUG) {
+    // eslint-disable-next-line no-console -- intentional debug surface
+    console.debug(`[hyperframes] ${label} swallowed:`, error);
+  }
+}
diff --git a/packages/core/src/runtime/init.ts b/packages/core/src/runtime/init.ts
index 25e685a8b..689126b2f 100644
--- a/packages/core/src/runtime/init.ts
+++ b/packages/core/src/runtime/init.ts
@@ -16,6 +16,7 @@ import { loadExternalCompositions, loadInlineTemplateCompositions } from "./comp
 import { applyCaptionOverrides } from "./captionOverrides";
 import type { RuntimeDeterministicAdapter, RuntimeJson, RuntimeTimelineLike } from "./types";
 import type { PlayerAPI } from "../core.types";
+import { swallow } from "./diagnostics";
 
 const AUTHORED_DURATION_ATTR = "data-hf-authored-duration";
 const AUTHORED_END_ATTR = "data-hf-authored-end";
@@ -33,8 +34,9 @@ export function initSandboxRuntimeModular(): void {
   if (typeof runtimeWindow.__hfRuntimeTeardown === "function") {
     try {
       runtimeWindow.__hfRuntimeTeardown();
-    } catch {
+    } catch (err) {
       // keep runtime resilient across reinits
+      swallow("runtime.init.site1", err);
     }
   }
   // Normalize html/body so browser defaults (8px margin, white background) never
@@ -583,8 +585,9 @@ export function initSandboxRuntimeModular(): void {
       if (existingRootTimeline) {
         try {
           fallbackTimeline.add(existingRootTimeline, 0);
-        } catch {
+        } catch (err) {
           // keep fallback resilient if root add fails
+          swallow("runtime.init.site2", err);
         }
       }
       const withTween = fallbackTimeline as RuntimeTimelineLike & {
@@ -593,8 +596,9 @@ export function initSandboxRuntimeModular(): void {
       if (typeof withTween.to === "function") {
         try {
           withTween.to({}, { duration: durationSeconds });
-        } catch {
+        } catch (err) {
           // no-op; if tween creation fails, caller will discard by unusable duration
+          swallow("runtime.init.site3", err);
         }
       }
       return fallbackTimeline;
@@ -622,8 +626,9 @@ export function initSandboxRuntimeModular(): void {
             const startSec = resolveCompositionStartSeconds(candidate.compositionId);
             rootTimeline.add(candidate.timeline, startSec);
             addedIds.push(candidate.compositionId);
-          } catch {
+          } catch (err) {
             // ignore broken child add attempts
+            swallow("runtime.init.site4", err);
           }
         }
         return addedIds;
@@ -687,8 +692,9 @@ export function initSandboxRuntimeModular(): void {
         if (typeof timelineWithPaused.paused !== "function") continue;
         try {
           timelineWithPaused.paused(false);
-        } catch {
+        } catch (err) {
           // keep runtime resilient against timeline API quirks
+          swallow("runtime.init.site5", err);
         }
       }
     };
@@ -828,8 +834,9 @@ export function initSandboxRuntimeModular(): void {
               // Placing a zero-duration tween at the floor extends
               // timeline.duration() to exactly that point.
               tlWithTo.to({}, { duration: 0 }, rootDurationFloorSeconds);
-            } catch {
+            } catch (err) {
               // keep runtime resilient
+              swallow("runtime.init.site6", err);
             }
           }
           const newDur = getTimelineDurationSeconds(rootTimeline);
@@ -1144,8 +1151,9 @@ export function initSandboxRuntimeModular(): void {
       if (wasPlaying) {
         state.capturedTimeline.play();
       }
-    } catch {
+    } catch (err) {
       // keep runtime resilient even if a timeline implementation throws
+      swallow("runtime.init.site7", err);
     }
     postRuntimeMessage({
       source: "hf-preview",
@@ -1410,14 +1418,16 @@ export function initSandboxRuntimeModular(): void {
         if (method === "discover") adapter.discover();
         if (method === "pause") adapter.pause();
         if (method === "play" && adapter.play) adapter.play();
-      } catch {
+      } catch (err) {
         // keep runtime resilient against adapter-specific failures
+        swallow("runtime.init.site8", err);
       }
       if (method === "discover") {
         try {
           adapter.seek({ time: timeSeconds });
-        } catch {
+        } catch (err) {
           // ignore seek bootstrap failures
+          swallow("runtime.init.site9", err);
         }
       }
     }
@@ -1479,8 +1489,9 @@ export function initSandboxRuntimeModular(): void {
       if (!(el instanceof HTMLMediaElement)) continue;
       try {
         el.playbackRate = state.playbackRate;
-      } catch {
+      } catch (err) {
         // ignore unsupported values
+        swallow("runtime.init.site10", err);
       }
     }
   };
@@ -1509,8 +1520,9 @@ export function initSandboxRuntimeModular(): void {
       for (const adapter of state.deterministicAdapters) {
         try {
           adapter.seek({ time: Number(timeSeconds) || 0 });
-        } catch {
+        } catch (err) {
           // ignore adapter failure
+          swallow("runtime.init.site11", err);
         }
       }
     },
@@ -1739,31 +1751,35 @@ export function initSandboxRuntimeModular(): void {
       if (!adapter || typeof adapter.revert !== "function") continue;
       try {
         adapter.revert();
-      } catch {
+      } catch (err) {
         // keep runtime resilient against adapter cleanup failures
+        swallow("runtime.init.site12", err);
       }
     }
     state.deterministicAdapters = [];
     for (const cleanup of runtimeCleanupCallbacks.splice(0)) {
       try {
         cleanup();
-      } catch {
+      } catch (err) {
         // ignore cleanup failures
+        swallow("runtime.init.site13", err);
       }
     }
     for (const styleEl of state.injectedCompStyles) {
       try {
         styleEl.remove();
-      } catch {
+      } catch (err) {
         // ignore cleanup failures
+        swallow("runtime.init.site14", err);
       }
     }
     state.injectedCompStyles = [];
     for (const scriptEl of state.injectedCompScripts) {
       try {
         scriptEl.remove();
-      } catch {
+      } catch (err) {
         // ignore cleanup failures
+        swallow("runtime.init.site15", err);
       }
     }
     state.injectedCompScripts = [];
diff --git a/packages/core/src/runtime/media.ts b/packages/core/src/runtime/media.ts
index 710999cb0..d4c0039e7 100644
--- a/packages/core/src/runtime/media.ts
+++ b/packages/core/src/runtime/media.ts
@@ -1,3 +1,4 @@
+import { swallow } from "./diagnostics";
 export type RuntimeMediaClip = {
   el: HTMLVideoElement | HTMLAudioElement;
   start: number;
@@ -160,8 +161,9 @@ export function syncRuntimeMedia(params: {
       try {
         // Per-element rate × global transport rate
         el.playbackRate = clip.playbackRate * params.playbackRate;
-      } catch {
+      } catch (err) {
         // ignore unsupported playbackRate
+        swallow("runtime.media.site1", err);
       }
       // Drift correction. Forcing `el.currentTime = relTime` every frame
       // causes an audible seek+rebuffer hiccup (readyState drops briefly).
@@ -194,8 +196,9 @@ export function syncRuntimeMedia(params: {
       if (drift > 0.5 && (firstTickOfClip || offsetJumped || catastrophicDrift)) {
         try {
           el.currentTime = relTime;
-        } catch {
+        } catch (err) {
           // ignore browser seek restrictions
+          swallow("runtime.media.site2", err);
         }
         // Detect failed seek: if currentTime didn't reach the target,
         // the browser can't seek past its buffered range. Common with
@@ -208,8 +211,9 @@ export function syncRuntimeMedia(params: {
           el.load();
           try {
             el.currentTime = relTime;
-          } catch {
+          } catch (err) {
             // ignore — the seek will be retried on the next tick
+            swallow("runtime.media.site3", err);
           }
         }
         // After a hard seek, clear the in-flight play guard so the next tick
diff --git a/packages/core/src/runtime/picker.ts b/packages/core/src/runtime/picker.ts
index 259db5747..733c01a40 100644
--- a/packages/core/src/runtime/picker.ts
+++ b/packages/core/src/runtime/picker.ts
@@ -1,4 +1,5 @@
 import type { RuntimeJson, RuntimeOutboundMessage, RuntimePickerElementInfo } from "./types";
+import { swallow } from "./diagnostics";
 
 type PickerModuleDeps = {
   postMessage: (payload: RuntimeOutboundMessage) => void;
@@ -33,8 +34,9 @@ export function createPickerModule(deps: PickerModuleDeps): PickerModule {
   function emitPickerRuntimeEvent(eventName: string, detail: RuntimeJson): void {
     try {
       window.dispatchEvent(new CustomEvent(eventName, { detail }));
-    } catch {
+    } catch (err) {
       // no-op in unsupported contexts
+      swallow("runtime.picker.site1", err);
     }
   }
 
diff --git a/packages/core/src/runtime/player.ts b/packages/core/src/runtime/player.ts
index d14776b0f..8da664d5d 100644
--- a/packages/core/src/runtime/player.ts
+++ b/packages/core/src/runtime/player.ts
@@ -1,5 +1,6 @@
 import type { RuntimePlayer, RuntimeTimelineLike } from "./types";
 import { quantizeTimeToFrame } from "../inline-scripts/parityContract";
+import { swallow } from "./diagnostics";
 
 type PlayerDeps = {
   getTimeline: () => RuntimeTimelineLike | null;
@@ -38,8 +39,9 @@ function forEachSiblingTimeline(
     if (!tl || tl === master) continue;
     try {
       fn(tl);
-    } catch {
+    } catch (err) {
       // ignore sibling failures — one broken timeline shouldn't poison play/pause
+      swallow("runtime.player.site1", err);
     }
   }
 }
@@ -76,8 +78,9 @@ function seekMasterAndSiblingTimelinesDeterministically(
     for (const tl of rearmedSiblings) {
       try {
         tl.pause();
-      } catch {
+      } catch (err) {
         // ignore sibling failures — one broken timeline shouldn't poison seek
+        swallow("runtime.player.site2", err);
       }
     }
   }
diff --git a/packages/core/src/runtime/startResolver.ts b/packages/core/src/runtime/startResolver.ts
index 214e57c31..20f872813 100644
--- a/packages/core/src/runtime/startResolver.ts
+++ b/packages/core/src/runtime/startResolver.ts
@@ -1,4 +1,5 @@
 import type { RuntimeTimelineLike } from "./types";
+import { swallow } from "./diagnostics";
 
 const AUTHORED_DURATION_ATTR = "data-hf-authored-duration";
 const AUTHORED_END_ATTR = "data-hf-authored-end";
@@ -118,8 +119,9 @@ export function createRuntimeStartTimeResolver(params: {
             if (Number.isFinite(timelineDuration) && timelineDuration > 0) {
               resolved = timelineDuration;
             }
-          } catch {
+          } catch (err) {
             // ignore broken timeline impls
+            swallow("runtime.startResolver.site1", err);
           }
         }
       }
diff --git a/packages/core/src/runtime/timeline.ts b/packages/core/src/runtime/timeline.ts
index 67e7ab0c3..f8246f2e8 100644
--- a/packages/core/src/runtime/timeline.ts
+++ b/packages/core/src/runtime/timeline.ts
@@ -4,6 +4,7 @@ import type {
   RuntimeTimelineScene,
   RuntimeTimelineLike,
 } from "./types";
+import { swallow } from "./diagnostics";
 import { createRuntimeStartTimeResolver } from "./startResolver";
 
 const AUTHORED_DURATION_ATTR = "data-hf-authored-duration";
@@ -565,8 +566,9 @@ export function collectRuntimeTimelinePayload(params: {
           });
           gsapClipIds.add(el.id);
         }
-      } catch {
+      } catch (err) {
         // GSAP introspection is best-effort — don't break timeline if it fails
+        swallow("runtime.timeline.site1", err);
       }
     }
   }