diff --git a/src/app/services/scheduled-task-executor-service.ts b/src/app/services/scheduled-task-executor-service.ts
index 3707d0e9..f5e64f0f 100644
--- a/src/app/services/scheduled-task-executor-service.ts
+++ b/src/app/services/scheduled-task-executor-service.ts
@@ -12,6 +12,8 @@ export const SCHEDULED_TASK_AGENT = "build";
 const SCHEDULED_TASK_SESSION_TITLE = "Scheduled task run";
 const EXECUTION_POLL_INTERVAL_MS = 2000;
 const MAX_IDLE_POLLS_WITHOUT_RESULT = 3;
+// Grace period for the server to start the session before any activity is seen.
+const MAX_STARTUP_POLLS_WITHOUT_ACTIVITY = 45;
 const COMPLETED_EMPTY_RESULT_RECHECK_INTERVAL_MS = 500;
 const MAX_COMPLETED_EMPTY_RESULT_RECHECKS = 3;
 const MODELS_DOCS_URL = "https://opencode.ai/docs/config/#models";
@@ -426,6 +428,8 @@ async function waitForScheduledTaskResult(
   const startedAtMs = Date.now();
   const executionTimeoutMs = getExecutionTimeoutMs();
   let idlePollsWithoutResult = 0;
+  let startupPollsWithoutActivity = 0;
+  let hasObservedActivity = false;
   let completedEmptyResultReadCount = 0;
 
   while (true) {
@@ -472,7 +476,13 @@ async function waitForScheduledTaskResult(
     }
 
     const sessionStatus = statuses[sessionId];
-    if (!sessionStatus || sessionStatus.type === "idle") {
+    const sessionIsActive = sessionStatus !== undefined && sessionStatus.type !== "idle";
+
+    if (sessionIsActive) {
+      hasObservedActivity = true;
+      idlePollsWithoutResult = 0;
+      startupPollsWithoutActivity = 0;
+    } else {
       const confirmedAssistantResult = await loadAssistantResult(sessionId, directory);
 
       if (confirmedAssistantResult.errorMessage) {
@@ -500,12 +510,17 @@ async function waitForScheduledTaskResult(
         continue;
       }
 
-      idlePollsWithoutResult += 1;
-      if (idlePollsWithoutResult >= MAX_IDLE_POLLS_WITHOUT_RESULT) {
-        throw new Error("Scheduled task finished without a completed assistant response");
+      if (hasObservedActivity) {
+        idlePollsWithoutResult += 1;
+        if (idlePollsWithoutResult >= MAX_IDLE_POLLS_WITHOUT_RESULT) {
+          throw new Error("Scheduled task finished without a completed assistant response");
+        }
+      } else {
+        startupPollsWithoutActivity += 1;
+        if (startupPollsWithoutActivity >= MAX_STARTUP_POLLS_WITHOUT_ACTIVITY) {
+          throw new Error("Scheduled task did not start producing a response in time");
+        }
       }
-    } else {
-      idlePollsWithoutResult = 0;
     }
 
     await sleep(EXECUTION_POLL_INTERVAL_MS);
diff --git a/tests/app/services/scheduled-task-executor-service.test.ts b/tests/app/services/scheduled-task-executor-service.test.ts
index 3aeec9b6..d74cdada 100644
--- a/tests/app/services/scheduled-task-executor-service.test.ts
+++ b/tests/app/services/scheduled-task-executor-service.test.ts
@@ -331,6 +331,51 @@ describe("app/services/scheduled-task-executor-service", () => {
     expect(mocked.deleteMock).toHaveBeenCalledWith({ sessionID: "session-1" });
   });
 
+  it("waits through startup before the server registers the session as active", async () => {
+    const { executeScheduledTask } = await import("../../../src/app/services/scheduled-task-executor-service.js");
+
+    mocked.createMock.mockResolvedValueOnce({
+      data: { id: "session-1", directory: "D:\\Projects\\Repo", title: "Scheduled task run" },
+      error: null,
+    });
+    mocked.promptAsyncMock.mockResolvedValueOnce({ data: undefined, error: null });
+
+    mocked.messagesMock.mockResolvedValue({
+      data: [createAssistantMessage("Started late but finished", { completed: true })],
+      error: null,
+    });
+    for (let index = 0; index < 7; index += 1) {
+      mocked.messagesMock.mockResolvedValueOnce({ data: [], error: null });
+    }
+
+    mocked.statusMock.mockResolvedValue({
+      data: { "session-1": { type: "busy" } },
+      error: null,
+    });
+    mocked.statusMock
+      .mockResolvedValueOnce({ data: {}, error: null })
+      .mockResolvedValueOnce({ data: {}, error: null })
+      .mockResolvedValueOnce({ data: {}, error: null });
+
+    vi.useFakeTimers();
+
+    const resultPromise = executeScheduledTask(createTask());
+
+    await vi.advanceTimersByTimeAsync(12000);
+
+    await expect(resultPromise).resolves.toMatchObject({
+      taskId: "task-1",
+      status: "success",
+      resultText: "Started late but finished",
+      errorMessage: null,
+    });
+    expect(mocked.statusMock.mock.calls.length).toBeGreaterThan(3);
+    expect(mocked.loggerWarnMock).not.toHaveBeenCalledWith(
+      expect.stringContaining("Scheduled task finished without a completed assistant response"),
+    );
+    expect(mocked.deleteMock).toHaveBeenCalledWith({ sessionID: "session-1" });
+  });
+
   it("treats an empty completed assistant reply as an execution error", async () => {
     const { executeScheduledTask } = await import("../../../src/app/services/scheduled-task-executor-service.js");