diff --git a/src/tui/local-run-shutdown.ts b/src/tui/local-run-shutdown.ts
index b4b975f23272..5bec3ad3ed2a 100644
--- a/src/tui/local-run-shutdown.ts
+++ b/src/tui/local-run-shutdown.ts
@@ -1,5 +1,8 @@
 // Coordinates graceful shutdown for local TUI runs.
-import { parseStrictNonNegativeInteger } from "../infra/parse-finite-number.js";
+import {
+  MAX_TIMER_TIMEOUT_MS,
+  parseStrictNonNegativeInteger,
+} from "../infra/parse-finite-number.js";
 
 // Local TUI runs get extra shutdown time because embedded agents/providers may still be closing.
 const LOCAL_RUN_SHUTDOWN_GRACE_MS = 120_000;
@@ -9,7 +12,7 @@ export function resolveLocalRunShutdownGraceMs(): number {
   const raw = process.env.OPENCLAW_TUI_LOCAL_RUN_SHUTDOWN_GRACE_MS?.trim();
   const parsed = parseStrictNonNegativeInteger(raw);
   if (parsed !== undefined) {
-    return parsed;
+    return Math.min(parsed, MAX_TIMER_TIMEOUT_MS);
   }
   return LOCAL_RUN_SHUTDOWN_GRACE_MS;
 }
diff --git a/src/tui/tui.test.ts b/src/tui/tui.test.ts
index a05a67f06f62..1f90313499df 100644
--- a/src/tui/tui.test.ts
+++ b/src/tui/tui.test.ts
@@ -2,6 +2,7 @@
 import { EventEmitter } from "node:events";
 import { describe, expect, it, vi } from "vitest";
 import type { OpenClawConfig } from "../config/config.js";
+import { MAX_TIMER_TIMEOUT_MS } from "../infra/parse-finite-number.js";
 import { MALFORMED_STREAMING_FRAGMENT_ERROR_MESSAGE } from "../shared/assistant-error-format.js";
 import { withEnv } from "../test-utils/env.js";
 import { getSlashCommands, parseCommand } from "./commands.js";
@@ -237,6 +238,14 @@ describe("resolveTuiShutdownHardExitMs", () => {
       expect(resolveTuiShutdownHardExitMs({ localMode: true })).toBe(122000);
     });
   });
+
+  it("clamps oversized local run shutdown grace values", () => {
+    withEnv({ OPENCLAW_TUI_LOCAL_RUN_SHUTDOWN_GRACE_MS: String(Number.MAX_SAFE_INTEGER) }, () => {
+      expect(resolveTuiShutdownHardExitMs({ localMode: true })).toBe(
+        MAX_TIMER_TIMEOUT_MS + 2000,
+      );
+    });
+  });
 });
 
 describe("resolveTuiSessionKey", () => {