From 7840fdbada9bb4b4ea397f8831cb69efe96a4387 Mon Sep 17 00:00:00 2001
From: Peter Steinberger <steipete@gmail.com>
Date: Sat, 30 May 2026 02:40:32 -0400
Subject: [PATCH] fix(agent-core): cap shell exec timeouts

---
 .../agent-core/src/harness/env/nodejs.test.ts | 21 +++++++++++++++
 packages/agent-core/src/harness/env/nodejs.ts | 26 ++++++++++++++++---
 2 files changed, 43 insertions(+), 4 deletions(-)
 create mode 100644 packages/agent-core/src/harness/env/nodejs.test.ts

diff --git a/packages/agent-core/src/harness/env/nodejs.test.ts b/packages/agent-core/src/harness/env/nodejs.test.ts
new file mode 100644
index 00000000000..919f1615de5
--- /dev/null
+++ b/packages/agent-core/src/harness/env/nodejs.test.ts
@@ -0,0 +1,21 @@
+import { describe, expect, it } from "vitest";
+import { resolveExecTimeoutMs } from "./nodejs.js";
+
+describe("NodeExecutionEnv timeout helpers", () => {
+  it("converts positive timeout seconds to milliseconds", () => {
+    expect(resolveExecTimeoutMs(1)).toBe(1_000);
+    expect(resolveExecTimeoutMs(1.5)).toBe(1_500);
+    expect(resolveExecTimeoutMs(0.0005)).toBe(1);
+  });
+
+  it("caps oversized timeout seconds to a timer-safe delay", () => {
+    expect(resolveExecTimeoutMs(Number.MAX_SAFE_INTEGER)).toBe(2_147_000_000);
+  });
+
+  it("ignores absent, invalid, or non-positive timeout seconds", () => {
+    expect(resolveExecTimeoutMs(undefined)).toBeUndefined();
+    expect(resolveExecTimeoutMs(Number.NaN)).toBeUndefined();
+    expect(resolveExecTimeoutMs(0)).toBeUndefined();
+    expect(resolveExecTimeoutMs(-1)).toBeUndefined();
+  });
+});
diff --git a/packages/agent-core/src/harness/env/nodejs.ts b/packages/agent-core/src/harness/env/nodejs.ts
index a112f4ac700..366d22b8fd3 100644
--- a/packages/agent-core/src/harness/env/nodejs.ts
+++ b/packages/agent-core/src/harness/env/nodejs.ts
@@ -29,10 +29,27 @@ import {
 } from "../types.js";
 import { killProcessTree } from "./kill-tree.js";
 
+const MAX_TIMER_TIMEOUT_MS = 2_147_000_000;
+
 function resolvePath(cwd: string, path: string): string {
   return isAbsolute(path) ? path : resolve(cwd, path);
 }
 
+export function resolveExecTimeoutMs(timeoutSeconds: unknown): number | undefined {
+  if (
+    typeof timeoutSeconds !== "number" ||
+    !Number.isFinite(timeoutSeconds) ||
+    timeoutSeconds <= 0
+  ) {
+    return undefined;
+  }
+  const milliseconds = Math.floor(timeoutSeconds * 1000);
+  if (!Number.isFinite(milliseconds) || milliseconds <= 0) {
+    return 1;
+  }
+  return Math.min(milliseconds, MAX_TIMER_TIMEOUT_MS);
+}
+
 function fileKindFromStats(stats: {
   isFile(): boolean;
   isDirectory(): boolean;
@@ -309,15 +326,16 @@ export class NodeExecutionEnv implements ExecutionEnv {
         return;
       }
 
+      const timeoutMs = resolveExecTimeoutMs(options?.timeout);
       timeoutId =
-        typeof options?.timeout === "number"
-          ? setTimeout(() => {
+        timeoutMs === undefined
+          ? undefined
+          : setTimeout(() => {
               timedOut = true;
               if (child?.pid) {
                 killProcessTree(child.pid, { force: true });
               }
-            }, options.timeout * 1000)
-          : undefined;
+            }, timeoutMs);
 
       if (options?.abortSignal) {
         if (options.abortSignal.aborted) {