diff --git a/docs/storybook-inventory.md b/docs/storybook-inventory.md
index 6ba03a951..5b0fe143b 100644
--- a/docs/storybook-inventory.md
+++ b/docs/storybook-inventory.md
@@ -8,6 +8,7 @@ buyer-facing control you can click before changing product CSS.
 | `Evidence/CitationChip` | Click a cited title to open that source post. | `--color-chip-border`, `--radius-chip`, `CitationChip` |
 | `AnalysisRun/CutoffKnownBody` | Read the cutoff-known sentence, then compare it with the live body below. | `--color-accent-border`, `--space-panel-block`, `--radius-panel`, `CutoffKnownBody` |
 | `Analysis/LineageEntityPicker` | Choose which corp to reconstruct, then click Request a lineage reconstruction. | `--space-control-gap`, `--size-control-min`, `--radius-control`, `LineageEntityPicker` |
+| `Admin/AdminPanel` | Change the tenant brand name, then verify the saved or failed state before leaving settings. | `--surface`, `--border`, `--space-panel-block`, `AdminPanel` |
 | `Lineage/LineageDag` | Open the current branch node; compare empty, grouped/forked, ungrouped, and long-title states before changing graph CSS. | `--surface`, `--border`, `LineageDag` |
 | `Chrome/PopupCloseButton` | Close the evidence panel or post popup. | `--space-close-inset`, `--font-size-close`, `PopupCloseButton` |
 
diff --git a/frontend/src/components/AdminPanel.stories.tsx b/frontend/src/components/AdminPanel.stories.tsx
new file mode 100644
index 000000000..f028de4b8
--- /dev/null
+++ b/frontend/src/components/AdminPanel.stories.tsx
@@ -0,0 +1,25 @@
+import type { Meta, StoryObj } from "@storybook/react-vite";
+import { AdminPanel } from "./AdminPanel";
+
+const meta = {
+  title: "Admin/AdminPanel",
+  component: AdminPanel,
+  args: {
+    currentBrandName: "LineageWeave",
+    onBrandNameChange: () => undefined,
+    accessToken: "demo-access-token",
+  },
+} satisfies Meta<typeof AdminPanel>;
+
+export default meta;
+
+type Story = StoryObj<typeof meta>;
+
+export const Default: Story = {};
+
+// Edge case: a long tenant brand name near the input's practical width.
+export const LongBrandName: Story = {
+  args: {
+    currentBrandName: "A Very Long Tenant Brand Name For Layout Testing Purposes",
+  },
+};
diff --git a/frontend/src/components/AdminPanel.test.tsx b/frontend/src/components/AdminPanel.test.tsx
new file mode 100644
index 000000000..c72b436a0
--- /dev/null
+++ b/frontend/src/components/AdminPanel.test.tsx
@@ -0,0 +1,83 @@
+import { act, fireEvent, render, screen } from "@testing-library/react";
+import userEvent from "@testing-library/user-event";
+import { afterEach, describe, expect, it, vi } from "vitest";
+import { AdminPanel } from "./AdminPanel";
+import * as api from "../api";
+
+describe("AdminPanel", () => {
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
+  it("ignores unchanged and whitespace-only submissions", async () => {
+    const updateSpy = vi.spyOn(api, "updateTenantConfig");
+    render(
+      <AdminPanel currentBrandName="LineageWeave" onBrandNameChange={vi.fn()} accessToken="token" />,
+    );
+    const button = screen.getByRole("button", { name: "Save settings" });
+    const input = screen.getByRole("textbox", { name: "Tenant brand name" });
+    const form = button.closest("form");
+
+    expect(button).toBeDisabled();
+    fireEvent.submit(form!);
+    await userEvent.clear(input);
+    await userEvent.type(input, "   ");
+    expect(button).toBeDisabled();
+    fireEvent.submit(form!);
+    expect(updateSpy).not.toHaveBeenCalled();
+  });
+
+  it("saves a changed brand name and reports it back to the caller", async () => {
+    const timeoutSpy = vi.spyOn(globalThis, "setTimeout");
+    const updateSpy = vi
+      .spyOn(api, "updateTenantConfig")
+      .mockResolvedValue({ brandName: "Renamed Corp" });
+    const onBrandNameChange = vi.fn();
+    render(
+      <AdminPanel currentBrandName="LineageWeave" onBrandNameChange={onBrandNameChange} accessToken="token" />,
+    );
+
+    const input = screen.getByRole("textbox", { name: "Tenant brand name" });
+    await userEvent.clear(input);
+    await userEvent.type(input, "Renamed Corp");
+    await userEvent.click(screen.getByRole("button", { name: "Save settings" }));
+
+    expect(updateSpy).toHaveBeenCalledWith("token", "Renamed Corp");
+    expect(await screen.findByRole("status")).toHaveTextContent("Settings saved!");
+    expect(onBrandNameChange).toHaveBeenCalledWith("Renamed Corp");
+    const timeoutIndex = timeoutSpy.mock.calls.findIndex((call) => call[1] === 3000);
+    expect(timeoutIndex).toBeGreaterThanOrEqual(0);
+    clearTimeout(timeoutSpy.mock.results[timeoutIndex].value);
+    act(() => (timeoutSpy.mock.calls[timeoutIndex][0] as () => void)());
+    expect(screen.queryByRole("status")).toBeNull();
+  });
+
+  it("shows an error and leaves the form editable when the save fails", async () => {
+    vi.spyOn(api, "updateTenantConfig").mockRejectedValue(new Error("Failed to update settings"));
+    render(
+      <AdminPanel currentBrandName="LineageWeave" onBrandNameChange={vi.fn()} accessToken="token" />,
+    );
+
+    const input = screen.getByRole("textbox", { name: "Tenant brand name" });
+    await userEvent.clear(input);
+    await userEvent.type(input, "Renamed Corp");
+    await userEvent.click(screen.getByRole("button", { name: "Save settings" }));
+
+    expect(await screen.findByRole("alert")).toHaveTextContent("Failed to update settings");
+    expect(screen.getByRole("button", { name: "Save settings" })).not.toBeDisabled();
+  });
+
+  it("uses the actionable fallback when a failure has no message", async () => {
+    vi.spyOn(api, "updateTenantConfig").mockRejectedValue(new Error(""));
+    render(
+      <AdminPanel currentBrandName="LineageWeave" onBrandNameChange={vi.fn()} accessToken="token" />,
+    );
+
+    const input = screen.getByRole("textbox", { name: "Tenant brand name" });
+    await userEvent.clear(input);
+    await userEvent.type(input, "Renamed Corp");
+    await userEvent.click(screen.getByRole("button", { name: "Save settings" }));
+
+    expect(await screen.findByRole("alert")).toHaveTextContent("Failed to update settings");
+  });
+});
diff --git a/frontend/src/components/AdminPanel.tsx b/frontend/src/components/AdminPanel.tsx
index af098f827..4f5ac2172 100644
--- a/frontend/src/components/AdminPanel.tsx
+++ b/frontend/src/components/AdminPanel.tsx
@@ -13,22 +13,22 @@ export function AdminPanel({ currentBrandName, onBrandNameChange, accessToken }:
   const [saved, setSaved] = useState(false);
   const [saving, setSaving] = useState(false);
   const [error, setError] = useState<string | null>(null);
+  const normalizedName = draftName.trim();
 
   async function handleSave(e: React.FormEvent) {
     e.preventDefault();
-    if (draftName.trim()) {
-      setSaving(true);
-      setError(null);
-      try {
-        const config = await updateTenantConfig(accessToken, draftName.trim());
-        onBrandNameChange(config.brandName);
-        setSaved(true);
-        setTimeout(() => setSaved(false), 3000);
-      } catch (err: any) {
-        setError(err.message || "Failed to update settings");
-      } finally {
-        setSaving(false);
-      }
+    if (!normalizedName || normalizedName === currentBrandName) return;
+    setSaving(true);
+    setError(null);
+    try {
+      const config = await updateTenantConfig(accessToken, normalizedName);
+      onBrandNameChange(config.brandName);
+      setSaved(true);
+      setTimeout(() => setSaved(false), 3000);
+    } catch (err: any) {
+      setError(err.message || "Failed to update settings");
+    } finally {
+      setSaving(false);
     }
   }
 
@@ -51,11 +51,11 @@ export function AdminPanel({ currentBrandName, onBrandNameChange, accessToken }:
           disabled={saving}
         />
         <div>
-          <button type="submit" className="btn-primary" disabled={saving || !draftName.trim() || draftName === currentBrandName}>
+          <button type="submit" className="btn-primary" disabled={saving || !normalizedName || normalizedName === currentBrandName}>
             {saving ? t("Saving...") : t("Save settings")}
           </button>
-          {saved && <span style={{ marginLeft: "1rem", color: "green" }}>{t("Settings saved!")}</span>}
-          {error && <span style={{ marginLeft: "1rem", color: "red" }}>{t(error)}</span>}
+          {saved && <span role="status" style={{ marginLeft: "1rem", color: "green" }}>{t("Settings saved!")}</span>}
+          {error && <span role="alert" style={{ marginLeft: "1rem", color: "red" }}>{t(error)}</span>}
         </div>
       </form>
     </div>