diff --git a/CHANGELOG.md b/CHANGELOG.md
index a54da3d139f..9afc20b9d93 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -65,6 +65,7 @@ Docs: https://docs.openclaw.ai
 - Talk/macOS: stop direct system-voice failures from replaying system speech, use app-locale fallback for shared watchdog timing, and add regression coverage for the macOS fallback route and language-aware timeout policy. (#53511) thanks @hongsw.
 - Discord/gateway cleanup: keep late Carbon reconnect-exhausted errors suppressed through startup/dispose cleanup so Discord monitor shutdown no longer crashes on late gateway close events. (#55373) Thanks @Takhoffman.
 - Discord/gateway shutdown: treat expected reconnect-exhausted events during intentional lifecycle stop as clean shutdowns so startup-abort cleanup no longer surfaces false gateway failures. (#55324) Thanks @joelnishanth.
+- GitHub Copilot/auth refresh: treat large `expires_at` values as seconds epochs and clamp far-future runtime auth refresh timers so Copilot token refresh cannot fall into a `setTimeout` overflow hot loop. (#55360) Thanks @michael-abdo.
 
 ## 2026.3.24
 
diff --git a/src/agents/github-copilot-token.test.ts b/src/agents/github-copilot-token.test.ts
new file mode 100644
index 00000000000..0bad7397c14
--- /dev/null
+++ b/src/agents/github-copilot-token.test.ts
@@ -0,0 +1,24 @@
+import { describe, expect, it, vi } from "vitest";
+import { resolveCopilotApiToken } from "./github-copilot-token.js";
+
+describe("resolveCopilotApiToken", () => {
+  it("treats 11-digit expires_at values as seconds epochs", async () => {
+    const fetchImpl = vi.fn(async () => ({
+      ok: true,
+      json: async () => ({
+        token: "copilot-token",
+        expires_at: 12_345_678_901,
+      }),
+    }));
+
+    const result = await resolveCopilotApiToken({
+      githubToken: "github-token",
+      cachePath: "/tmp/github-copilot-token-test.json",
+      loadJsonFileImpl: () => undefined,
+      saveJsonFileImpl: () => undefined,
+      fetchImpl: fetchImpl as unknown as typeof fetch,
+    });
+
+    expect(result.expiresAt).toBe(12_345_678_901_000);
+  });
+});
diff --git a/src/agents/github-copilot-token.ts b/src/agents/github-copilot-token.ts
index a5d9a6b1e8e..ee0d09098a2 100644
--- a/src/agents/github-copilot-token.ts
+++ b/src/agents/github-copilot-token.ts
@@ -36,15 +36,16 @@ function parseCopilotTokenResponse(value: unknown): {
   }
 
   // GitHub returns a unix timestamp (seconds), but we defensively accept ms too.
+  // Use a 1e11 threshold so large seconds-epoch values are not misread as ms.
   let expiresAtMs: number;
   if (typeof expiresAt === "number" && Number.isFinite(expiresAt)) {
-    expiresAtMs = expiresAt > 10_000_000_000 ? expiresAt : expiresAt * 1000;
+    expiresAtMs = expiresAt < 100_000_000_000 ? expiresAt * 1000 : expiresAt;
   } else if (typeof expiresAt === "string" && expiresAt.trim().length > 0) {
     const parsed = Number.parseInt(expiresAt, 10);
     if (!Number.isFinite(parsed)) {
       throw new Error("Copilot token response has invalid expires_at");
     }
-    expiresAtMs = parsed > 10_000_000_000 ? parsed : parsed * 1000;
+    expiresAtMs = parsed < 100_000_000_000 ? parsed * 1000 : parsed;
   } else {
     throw new Error("Copilot token response missing expires_at");
   }
diff --git a/src/agents/pi-embedded-runner/run.ts b/src/agents/pi-embedded-runner/run.ts
index 22e26cd9628..da37d9ee69a 100644
--- a/src/agents/pi-embedded-runner/run.ts
+++ b/src/agents/pi-embedded-runner/run.ts
@@ -63,6 +63,7 @@ import {
   parseImageSizeError,
   pickFallbackThinkingLevel,
 } from "../pi-embedded-helpers.js";
+import { clampRuntimeAuthRefreshDelayMs } from "../runtime-auth-refresh.js";
 import { ensureRuntimePluginsLoaded } from "../runtime-plugins.js";
 import { isLikelyMutatingToolName } from "../tool-mutation.js";
 import { derivePromptTokens, normalizeUsage, type UsageLike } from "../usage.js";
@@ -507,7 +508,11 @@ export async function runEmbeddedPiAgent(
         clearRuntimeAuthRefreshTimer();
         const now = Date.now();
         const refreshAt = runtimeAuthState.expiresAt - RUNTIME_AUTH_REFRESH_MARGIN_MS;
-        const delayMs = Math.max(RUNTIME_AUTH_REFRESH_MIN_DELAY_MS, refreshAt - now);
+        const delayMs = clampRuntimeAuthRefreshDelayMs({
+          refreshAt,
+          now,
+          minDelayMs: RUNTIME_AUTH_REFRESH_MIN_DELAY_MS,
+        });
         const timer = setTimeout(() => {
           if (runtimeAuthRefreshCancelled) {
             return;
diff --git a/src/agents/runtime-auth-refresh.test.ts b/src/agents/runtime-auth-refresh.test.ts
new file mode 100644
index 00000000000..b57eeb27b5c
--- /dev/null
+++ b/src/agents/runtime-auth-refresh.test.ts
@@ -0,0 +1,24 @@
+import { describe, expect, it } from "vitest";
+import { clampRuntimeAuthRefreshDelayMs } from "./runtime-auth-refresh.js";
+
+describe("clampRuntimeAuthRefreshDelayMs", () => {
+  it("clamps far-future refresh delays to a timer-safe ceiling", () => {
+    expect(
+      clampRuntimeAuthRefreshDelayMs({
+        refreshAt: 12_345_678_901_000,
+        now: 0,
+        minDelayMs: 60_000,
+      }),
+    ).toBe(2_147_483_647);
+  });
+
+  it("still respects the configured minimum delay", () => {
+    expect(
+      clampRuntimeAuthRefreshDelayMs({
+        refreshAt: 1_000,
+        now: 900,
+        minDelayMs: 60_000,
+      }),
+    ).toBe(60_000);
+  });
+});
diff --git a/src/agents/runtime-auth-refresh.ts b/src/agents/runtime-auth-refresh.ts
new file mode 100644
index 00000000000..0860e1e4031
--- /dev/null
+++ b/src/agents/runtime-auth-refresh.ts
@@ -0,0 +1,9 @@
+const MAX_SAFE_TIMEOUT_MS = 2_147_483_647;
+
+export function clampRuntimeAuthRefreshDelayMs(params: {
+  refreshAt: number;
+  now: number;
+  minDelayMs: number;
+}): number {
+  return Math.min(MAX_SAFE_TIMEOUT_MS, Math.max(params.minDelayMs, params.refreshAt - params.now));
+}