diff --git a/src/agents/bash-tools.process.poll-timeout.test.ts b/src/agents/bash-tools.process.poll-timeout.test.ts
index e72d95a34..44e3bb741 100644
--- a/src/agents/bash-tools.process.poll-timeout.test.ts
+++ b/src/agents/bash-tools.process.poll-timeout.test.ts
@@ -1,56 +1,100 @@
-import { afterEach, expect, test } from "vitest";
-import { resetProcessRegistryForTests } from "./bash-process-registry.js";
-import { createExecTool } from "./bash-tools.exec.js";
+import { afterEach, expect, test, vi } from "vitest";
+import type { ProcessSession } from "./bash-process-registry.js";
+import {
+  addSession,
+  appendOutput,
+  markExited,
+  resetProcessRegistryForTests,
+} from "./bash-process-registry.js";
 import { createProcessTool } from "./bash-tools.process.js";
 
 afterEach(() => {
   resetProcessRegistryForTests();
 });
 
-const sleepAndEcho =
-  process.platform === "win32"
-    ? "Start-Sleep -Milliseconds 300; Write-Output done"
-    : "sleep 0.3; echo done";
+function createBackgroundSession(id: string): ProcessSession {
+  return {
+    id,
+    command: "test",
+    startedAt: Date.now(),
+    cwd: "/tmp",
+    maxOutputChars: 10_000,
+    pendingMaxOutputChars: 30_000,
+    totalOutputChars: 0,
+    pendingStdout: [],
+    pendingStderr: [],
+    pendingStdoutChars: 0,
+    pendingStderrChars: 0,
+    aggregated: "",
+    tail: "",
+    exited: false,
+    exitCode: undefined,
+    exitSignal: undefined,
+    truncated: false,
+    backgrounded: true,
+  };
+}
 
 test("process poll waits for completion when timeout is provided", async () => {
-  const execTool = createExecTool();
-  const processTool = createProcessTool();
-  const started = Date.now();
-  const run = await execTool.execute("toolcall", {
-    command: sleepAndEcho,
-    background: true,
-  });
-  expect(run.details.status).toBe("running");
-  const sessionId = run.details.sessionId;
+  vi.useFakeTimers();
+  try {
+    const processTool = createProcessTool();
+    const sessionId = "sess";
+    const session = createBackgroundSession(sessionId);
+    addSession(session);
 
-  const poll = await processTool.execute("toolcall", {
-    action: "poll",
-    sessionId,
-    timeout: 2000,
-  });
-  const elapsedMs = Date.now() - started;
-  const details = poll.details as { status?: string; aggregated?: string };
-  expect(details.status).toBe("completed");
-  expect(details.aggregated ?? "").toContain("done");
-  expect(elapsedMs).toBeGreaterThanOrEqual(200);
+    setTimeout(() => {
+      appendOutput(session, "stdout", "done\n");
+      markExited(session, 0, null, "completed");
+    }, 10);
+
+    const pollPromise = processTool.execute("toolcall", {
+      action: "poll",
+      sessionId,
+      timeout: 2000,
+    });
+
+    let resolved = false;
+    void pollPromise.finally(() => {
+      resolved = true;
+    });
+
+    await vi.advanceTimersByTimeAsync(200);
+    expect(resolved).toBe(false);
+
+    await vi.advanceTimersByTimeAsync(100);
+    const poll = await pollPromise;
+    const details = poll.details as { status?: string; aggregated?: string };
+    expect(details.status).toBe("completed");
+    expect(details.aggregated ?? "").toContain("done");
+  } finally {
+    vi.useRealTimers();
+  }
 });
 
 test("process poll accepts string timeout values", async () => {
-  const execTool = createExecTool();
-  const processTool = createProcessTool();
-  const run = await execTool.execute("toolcall", {
-    command: sleepAndEcho,
-    background: true,
-  });
-  expect(run.details.status).toBe("running");
-  const sessionId = run.details.sessionId;
+  vi.useFakeTimers();
+  try {
+    const processTool = createProcessTool();
+    const sessionId = "sess-2";
+    const session = createBackgroundSession(sessionId);
+    addSession(session);
+    setTimeout(() => {
+      appendOutput(session, "stdout", "done\n");
+      markExited(session, 0, null, "completed");
+    }, 10);
 
-  const poll = await processTool.execute("toolcall", {
-    action: "poll",
-    sessionId,
-    timeout: "2000",
-  });
-  const details = poll.details as { status?: string; aggregated?: string };
-  expect(details.status).toBe("completed");
-  expect(details.aggregated ?? "").toContain("done");
+    const pollPromise = processTool.execute("toolcall", {
+      action: "poll",
+      sessionId,
+      timeout: "2000",
+    });
+    await vi.advanceTimersByTimeAsync(350);
+    const poll = await pollPromise;
+    const details = poll.details as { status?: string; aggregated?: string };
+    expect(details.status).toBe("completed");
+    expect(details.aggregated ?? "").toContain("done");
+  } finally {
+    vi.useRealTimers();
+  }
 });