diff --git a/packages/core/src/runtime/player.test.ts b/packages/core/src/runtime/player.test.ts
index d066b51d3..13d1cadbe 100644
--- a/packages/core/src/runtime/player.test.ts
+++ b/packages/core/src/runtime/player.test.ts
@@ -488,6 +488,73 @@ describe("createRuntimePlayer", () => {
     });
   });
 
+  describe("tolerates non-conformant timeline objects", () => {
+    it("handles duration as a number property instead of a function", () => {
+      const timeline = {
+        play: vi.fn(),
+        pause: vi.fn(),
+        seek: vi.fn(),
+        totalTime: vi.fn(),
+        time: vi.fn(() => 2),
+        duration: 10,
+        add: vi.fn(),
+        paused: vi.fn(),
+        set: vi.fn(),
+      } as unknown as RuntimeTimelineLike;
+      const deps = createMockDeps(timeline);
+      const player = createRuntimePlayer(deps);
+      expect(player.getDuration()).toBe(10);
+      expect(() => player.play()).not.toThrow();
+    });
+
+    it("handles missing pause method", () => {
+      const timeline = {
+        play: vi.fn(),
+        seek: vi.fn(),
+        time: vi.fn(() => 0),
+        duration: vi.fn(() => 10),
+        add: vi.fn(),
+        paused: vi.fn(),
+        set: vi.fn(),
+      } as unknown as RuntimeTimelineLike;
+      const deps = createMockDeps(timeline);
+      const player = createRuntimePlayer(deps);
+      expect(() => player.pause()).not.toThrow();
+      expect(() => player.seek(3)).not.toThrow();
+    });
+
+    it("handles missing play method", () => {
+      const timeline = {
+        pause: vi.fn(),
+        seek: vi.fn(),
+        time: vi.fn(() => 0),
+        duration: vi.fn(() => 10),
+        add: vi.fn(),
+        paused: vi.fn(),
+        set: vi.fn(),
+      } as unknown as RuntimeTimelineLike;
+      const deps = createMockDeps(timeline);
+      const player = createRuntimePlayer(deps);
+      expect(() => player.play()).not.toThrow();
+    });
+
+    it("handles time as a number property instead of a function", () => {
+      const timeline = {
+        play: vi.fn(),
+        pause: vi.fn(),
+        seek: vi.fn(),
+        time: 5,
+        duration: vi.fn(() => 10),
+        add: vi.fn(),
+        paused: vi.fn(),
+        set: vi.fn(),
+      } as unknown as RuntimeTimelineLike;
+      const deps = createMockDeps(timeline);
+      const player = createRuntimePlayer(deps);
+      expect(player.getTime()).toBe(5);
+    });
+  });
+
   describe("getters", () => {
     it("getTime returns timeline time", () => {
       const timeline = createMockTimeline({ time: 7.5 });
diff --git a/packages/core/src/runtime/player.ts b/packages/core/src/runtime/player.ts
index 9d1ef263b..d28f3592a 100644
--- a/packages/core/src/runtime/player.ts
+++ b/packages/core/src/runtime/player.ts
@@ -2,6 +2,35 @@ import type { RuntimePlayer, RuntimeTimelineLike } from "./types";
 import { quantizeTimeToFrame } from "../inline-scripts/parityContract";
 import { swallow } from "./diagnostics";
 
+/**
+ * Safely read a numeric value from a timeline property that may be either a
+ * function (conformant GSAP) or a bare number (user-authored timeline-like).
+ */
+function safeNum(obj: unknown, prop: string, fallback: number): number {
+  const val = (obj as Record<string, unknown>)?.[prop];
+  if (typeof val === "function") return Number(val.call(obj)) || fallback;
+  if (typeof val === "number" && Number.isFinite(val)) return val;
+  if (val !== undefined && val !== null) {
+    swallow("runtime.player.nonConformantNum", { prop, actual: typeof val });
+  }
+  return fallback;
+}
+
+/**
+ * Safely invoke a void method on a timeline. If the method is not a function
+ * (missing or overwritten with a non-callable value), silently skip.
+ */
+function safeVoid(obj: unknown, method: string): void {
+  const fn = (obj as Record<string, unknown>)?.[method];
+  if (typeof fn === "function") {
+    fn.call(obj);
+    return;
+  }
+  if (fn !== undefined) {
+    swallow("runtime.player.nonConformantVoid", { method, actual: typeof fn });
+  }
+}
+
 type PlayerDeps = {
   getTimeline: () => RuntimeTimelineLike | null;
   setTimeline: (timeline: RuntimeTimelineLike | null) => void;
@@ -52,11 +81,11 @@ function seekTimelineDeterministically(
   canonicalFps: number,
 ): number {
   const quantized = quantizeTimeToFrame(timeSeconds, canonicalFps);
-  timeline.pause();
+  safeVoid(timeline, "pause");
   if (typeof timeline.totalTime === "function") {
     timeline.totalTime(quantized, false);
   } else {
-    timeline.seek(quantized, false);
+    if (typeof timeline.seek === "function") timeline.seek(quantized, false);
   }
   return quantized;
 }
@@ -69,7 +98,7 @@ function seekMasterAndSiblingTimelinesDeterministically(
 ): number {
   const rearmedSiblings: RuntimeTimelineLike[] = [];
   forEachSiblingTimeline(registry, master, (tl) => {
-    tl.play();
+    safeVoid(tl, "play");
     rearmedSiblings.push(tl);
   });
   try {
@@ -77,7 +106,7 @@ function seekMasterAndSiblingTimelinesDeterministically(
   } finally {
     for (const tl of rearmedSiblings) {
       try {
-        tl.pause();
+        safeVoid(tl, "pause");
       } catch (err) {
         // ignore sibling failures — one broken timeline shouldn't poison seek
         swallow("runtime.player.site2", err);
@@ -91,7 +120,7 @@ function activateSiblingTimelines(
   master: RuntimeTimelineLike,
 ): void {
   forEachSiblingTimeline(registry, master, (tl) => {
-    tl.play();
+    safeVoid(tl, "play");
   });
 }
 
@@ -103,13 +132,13 @@ export function createRuntimePlayer(deps: PlayerDeps): RuntimePlayer {
       if (!timeline || deps.getIsPlaying()) return;
       const safeDuration = Math.max(
         0,
-        Number(deps.getSafeDuration?.() ?? timeline.duration() ?? 0) || 0,
+        Number(deps.getSafeDuration?.() ?? safeNum(timeline, "duration", 0)) || 0,
       );
       if (safeDuration > 0) {
-        const currentTime = Math.max(0, Number(timeline.time()) || 0);
+        const currentTime = Math.max(0, safeNum(timeline, "time", 0));
         if (currentTime >= safeDuration) {
-          timeline.pause();
-          timeline.seek(0, false);
+          safeVoid(timeline, "pause");
+          if (typeof timeline.seek === "function") timeline.seek(0, false);
           deps.onDeterministicSeek(0);
           deps.setIsPlaying(false);
           deps.onSyncMedia(0, false);
@@ -119,10 +148,10 @@ export function createRuntimePlayer(deps: PlayerDeps): RuntimePlayer {
       if (typeof timeline.timeScale === "function") {
         timeline.timeScale(deps.getPlaybackRate());
       }
-      timeline.play();
+      safeVoid(timeline, "play");
       forEachSiblingTimeline(deps.getTimelineRegistry?.(), timeline, (tl) => {
         if (typeof tl.timeScale === "function") tl.timeScale(deps.getPlaybackRate());
-        tl.play();
+        safeVoid(tl, "play");
       });
       deps.onDeterministicPlay();
       deps.setIsPlaying(true);
@@ -132,11 +161,11 @@ export function createRuntimePlayer(deps: PlayerDeps): RuntimePlayer {
     pause: () => {
       const timeline = deps.getTimeline();
       if (!timeline) return;
-      timeline.pause();
+      safeVoid(timeline, "pause");
       forEachSiblingTimeline(deps.getTimelineRegistry?.(), timeline, (tl) => {
-        tl.pause();
+        safeVoid(tl, "pause");
       });
-      const time = Math.max(0, Number(timeline.time()) || 0);
+      const time = Math.max(0, safeNum(timeline, "time", 0));
       deps.onDeterministicSeek(time);
       deps.onDeterministicPause();
       deps.setIsPlaying(false);
@@ -162,10 +191,10 @@ export function createRuntimePlayer(deps: PlayerDeps): RuntimePlayer {
         if (typeof timeline.timeScale === "function") {
           timeline.timeScale(deps.getPlaybackRate());
         }
-        timeline.play();
+        safeVoid(timeline, "play");
         forEachSiblingTimeline(deps.getTimelineRegistry?.(), timeline, (tl) => {
           if (typeof tl.timeScale === "function") tl.timeScale(deps.getPlaybackRate());
-          tl.play();
+          safeVoid(tl, "play");
         });
         deps.onDeterministicPlay();
         deps.onShowNativeVideos();
@@ -199,8 +228,8 @@ export function createRuntimePlayer(deps: PlayerDeps): RuntimePlayer {
       deps.onRenderFrameSeek(quantized);
       deps.onStatePost(true);
     },
-    getTime: () => Number(deps.getTimeline()?.time() ?? 0),
-    getDuration: () => Number(deps.getTimeline()?.duration() ?? 0),
+    getTime: () => safeNum(deps.getTimeline(), "time", 0),
+    getDuration: () => safeNum(deps.getTimeline(), "duration", 0),
     isPlaying: () => deps.getIsPlaying(),
     setPlaybackRate: (rate: number) => deps.setPlaybackRate(rate),
     getPlaybackRate: () => deps.getPlaybackRate(),