feat(KB-101): add ntfy notification test button in settings

- Add /api/settings/test-ntfy endpoint for sending test notifications
- Add test notification button to SettingsModal when ntfy is enabled
- Display success/error feedback after test notification attempt
- Add comprehensive tests for test notification flow
- Include changeset for patch release

packages/dashboard/app/api.ts

@@ -152,6 +152,12 @@ export function updateSettings(settings: Partial<Settings>): Promise<Settings> {
   });
 }
 
+export function testNtfyNotification(): Promise<{ success: boolean }> {
+  return api<{ success: boolean }>("/settings/test-ntfy", {
+    method: "POST",
+  });
+}
+
 export async function uploadAttachment(id: string, file: File): Promise<TaskAttachment> {
   const formData = new FormData();
   formData.append("file", file);

packages/dashboard/app/components/SettingsModal.tsx

@@ -1,7 +1,7 @@
 import { useState, useEffect, useCallback, useRef } from "react";
 import { THINKING_LEVELS } from "@kb/core";
 import type { Settings, ThemeMode, ColorTheme } from "@kb/core";
-import { fetchSettings, updateSettings, fetchAuthStatus, loginProvider, logoutProvider, fetchModels } from "../api";
+import { fetchSettings, updateSettings, fetchAuthStatus, loginProvider, logoutProvider, fetchModels, testNtfyNotification } from "../api";
 import type { AuthProvider, ModelInfo } from "../api";
 import type { ToastType } from "../hooks/useToast";
 import { ThemeSelector } from "./ThemeSelector";
@@ -79,6 +79,9 @@ export function SettingsModal({
   const [availableModels, setAvailableModels] = useState<ModelInfo[]>([]);
   const [modelsLoading, setModelsLoading] = useState(false);
 
+  // Test notification state
+  const [testNotificationLoading, setTestNotificationLoading] = useState(false);
+
   useEffect(() => {
     fetchSettings()
       .then((s) => {
@@ -168,6 +171,27 @@ export function SettingsModal({
     }
   }, [addToast, loadAuthStatus]);
 
+  const handleTestNotification = useCallback(async () => {
+    // Validate ntfy is enabled and topic is valid
+    if (!form.ntfyEnabled || !form.ntfyTopic || !/^[a-zA-Z0-9_-]{1,64}$/.test(form.ntfyTopic)) {
+      return;
+    }
+
+    setTestNotificationLoading(true);
+    try {
+      const result = await testNtfyNotification();
+      if (result.success) {
+        addToast("Test notification sent — check your ntfy app!", "success");
+      } else {
+        addToast("Failed to send test notification", "error");
+      }
+    } catch (err: any) {
+      addToast(err.message || "Failed to send test notification", "error");
+    } finally {
+      setTestNotificationLoading(false);
+    }
+  }, [addToast, form.ntfyEnabled, form.ntfyTopic]);
+
   useEffect(() => {
     const handleKey = (e: KeyboardEvent) => {
       if (e.key === "Escape") onClose();
@@ -586,6 +610,18 @@ export function SettingsModal({
                     Topic must be 1–64 alphanumeric, hyphen, or underscore characters
                   </small>
                 )}
+                <button
+                  type="button"
+                  className="btn btn-sm"
+                  onClick={handleTestNotification}
+                  disabled={
+                    testNotificationLoading ||
+                    !form.ntfyTopic ||
+                    !/^[a-zA-Z0-9_-]{1,64}$/.test(form.ntfyTopic)
+                  }
+                >
+                  {testNotificationLoading ? "Sending…" : "Test notification"}
+                </button>
               </div>
             )}
           </>

packages/dashboard/app/components/__tests__/SettingsModal.test.tsx

@@ -31,9 +31,10 @@ vi.mock("../../api", () => ({
     { provider: "anthropic", id: "claude-sonnet-4-5", name: "Claude Sonnet 4.5", reasoning: true, contextWindow: 200000 },
     { provider: "openai", id: "gpt-4o", name: "GPT-4o", reasoning: false, contextWindow: 128000 },
   ])),
+  testNtfyNotification: vi.fn(() => Promise.resolve({ success: true })),
 }));
 
-import { fetchSettings, updateSettings, fetchAuthStatus, loginProvider, logoutProvider, fetchModels } from "../../api";
+import { fetchSettings, updateSettings, fetchAuthStatus, loginProvider, logoutProvider, fetchModels, testNtfyNotification } from "../../api";
 
 const onClose = vi.fn();
 const addToast = vi.fn();
@@ -1034,4 +1035,121 @@ describe("SettingsModal", () => {
     expect(screen.getByText(/No models match/)).toBeTruthy();
     expect(screen.getByText("0 models")).toBeTruthy();
   });
+
+  // --- Test notification button tests ---
+
+  it("Test notification button is disabled when ntfy is disabled", async () => {
+    render(<SettingsModal onClose={onClose} addToast={addToast} />);
+    await waitFor(() => expect(fetchSettings).toHaveBeenCalled());
+
+    fireEvent.click(screen.getByText("Notifications"));
+
+    // When ntfy is disabled, the topic input (and test button) should not be visible
+    expect(screen.queryByLabelText("ntfy Topic")).toBeNull();
+    expect(screen.queryByRole("button", { name: /Test notification/i })).toBeNull();
+  });
+
+  it("Test notification button is disabled when topic is invalid", async () => {
+    render(<SettingsModal onClose={onClose} addToast={addToast} />);
+    await waitFor(() => expect(fetchSettings).toHaveBeenCalled());
+
+    fireEvent.click(screen.getByText("Notifications"));
+
+    // Enable ntfy
+    const checkbox = screen.getByLabelText("Enable ntfy.sh notifications");
+    fireEvent.click(checkbox);
+
+    // Enter invalid topic
+    const input = screen.getByLabelText("ntfy Topic") as HTMLInputElement;
+    fireEvent.change(input, { target: { value: "invalid topic with spaces!" } });
+
+    // Test button should be disabled
+    const testButton = screen.getByRole("button", { name: "Test notification" });
+    expect(testButton).toBeDisabled();
+  });
+
+  it("Test notification button is enabled when ntfy is enabled with valid topic", async () => {
+    render(<SettingsModal onClose={onClose} addToast={addToast} />);
+    await waitFor(() => expect(fetchSettings).toHaveBeenCalled());
+
+    fireEvent.click(screen.getByText("Notifications"));
+
+    // Enable ntfy
+    const checkbox = screen.getByLabelText("Enable ntfy.sh notifications");
+    fireEvent.click(checkbox);
+
+    // Enter valid topic
+    const input = screen.getByLabelText("ntfy Topic") as HTMLInputElement;
+    fireEvent.change(input, { target: { value: "my-valid-topic" } });
+
+    // Test button should be enabled
+    const testButton = screen.getByRole("button", { name: "Test notification" });
+    expect(testButton).toBeEnabled();
+  });
+
+  it("Clicking test button calls testNtfyNotification API", async () => {
+    render(<SettingsModal onClose={onClose} addToast={addToast} />);
+    await waitFor(() => expect(fetchSettings).toHaveBeenCalled());
+
+    fireEvent.click(screen.getByText("Notifications"));
+
+    // Enable ntfy
+    const checkbox = screen.getByLabelText("Enable ntfy.sh notifications");
+    fireEvent.click(checkbox);
+
+    // Enter valid topic
+    const input = screen.getByLabelText("ntfy Topic") as HTMLInputElement;
+    fireEvent.change(input, { target: { value: "my-valid-topic" } });
+
+    // Click test button
+    const testButton = screen.getByRole("button", { name: "Test notification" });
+    fireEvent.click(testButton);
+
+    await waitFor(() => expect(testNtfyNotification).toHaveBeenCalledTimes(1));
+  });
+
+  it("Success toast is shown when test notification succeeds", async () => {
+    render(<SettingsModal onClose={onClose} addToast={addToast} />);
+    await waitFor(() => expect(fetchSettings).toHaveBeenCalled());
+
+    fireEvent.click(screen.getByText("Notifications"));
+
+    // Enable ntfy
+    const checkbox = screen.getByLabelText("Enable ntfy.sh notifications");
+    fireEvent.click(checkbox);
+
+    // Enter valid topic
+    const input = screen.getByLabelText("ntfy Topic") as HTMLInputElement;
+    fireEvent.change(input, { target: { value: "my-valid-topic" } });
+
+    // Click test button
+    const testButton = screen.getByRole("button", { name: "Test notification" });
+    fireEvent.click(testButton);
+
+    await waitFor(() => expect(addToast).toHaveBeenCalledWith("Test notification sent — check your ntfy app!", "success"));
+  });
+
+  it("Error toast is shown when test notification fails", async () => {
+    // Mock the API to return an error
+    (testNtfyNotification as ReturnType<typeof vi.fn>).mockRejectedValueOnce(new Error("Network error"));
+
+    render(<SettingsModal onClose={onClose} addToast={addToast} />);
+    await waitFor(() => expect(fetchSettings).toHaveBeenCalled());
+
+    fireEvent.click(screen.getByText("Notifications"));
+
+    // Enable ntfy
+    const checkbox = screen.getByLabelText("Enable ntfy.sh notifications");
+    fireEvent.click(checkbox);
+
+    // Enter valid topic
+    const input = screen.getByLabelText("ntfy Topic") as HTMLInputElement;
+    fireEvent.change(input, { target: { value: "my-valid-topic" } });
+
+    // Click test button
+    const testButton = screen.getByRole("button", { name: "Test notification" });
+    fireEvent.click(testButton);
+
+    await waitFor(() => expect(addToast).toHaveBeenCalledWith("Network error", "error"));
+  });
 });

packages/dashboard/src/routes.ts

@@ -605,6 +605,53 @@ export function createApiRoutes(store: TaskStore, options?: ServerOptions): Rout
     }
   });
 
+  /**
+   * POST /api/settings/test-ntfy
+   * Send a test notification to verify ntfy configuration.
+   * Returns: { success: true } on success, { error: string } on failure.
+   */
+  router.post("/settings/test-ntfy", async (_req, res) => {
+    try {
+      const settings = await store.getSettings();
+
+      // Validate ntfy is enabled
+      if (!settings.ntfyEnabled) {
+        res.status(400).json({ error: "ntfy notifications are not enabled" });
+        return;
+      }
+
+      // Validate topic exists and matches required format
+      const topic = settings.ntfyTopic;
+      if (!topic || !/^[a-zA-Z0-9_-]{1,64}$/.test(topic)) {
+        res.status(400).json({ error: "ntfy topic is not configured or invalid" });
+        return;
+      }
+
+      // Send test notification to ntfy.sh
+      const ntfyBaseUrl = "https://ntfy.sh";
+      const url = `${ntfyBaseUrl}/${topic}`;
+
+      const response = await fetch(url, {
+        method: "POST",
+        headers: {
+          "Title": "kb test notification",
+          "Priority": "default",
+          "Content-Type": "text/plain",
+        },
+        body: "kb test notification — your notifications are working!",
+      });
+
+      if (!response.ok) {
+        res.status(502).json({ error: `ntfy.sh returned ${response.status}: ${response.statusText}` });
+        return;
+      }
+
+      res.json({ success: true });
+    } catch (err: any) {
+      res.status(500).json({ error: err.message ?? "Failed to send test notification" });
+    }
+  });
+
   // Models
   registerModelsRoute(router, options?.modelRegistry);