diff --git a/.changeset/fn-7882-copy-diagnostics-fix.md b/.changeset/fn-7882-copy-diagnostics-fix.md
new file mode 100644
index 0000000000..b0c6807762
--- /dev/null
+++ b/.changeset/fn-7882-copy-diagnostics-fix.md
@@ -0,0 +1,7 @@
+---
+"@runfusion/fusion": patch
+---
+
+summary: Fix "Copy diagnostics" crash on non-secure origins (mobile/HTTP).
+category: fix
+dev: Command Center System tab now routes diagnostics copy through copyTextToClipboard (secure-context guard + execCommand fallback) instead of navigator.clipboard.writeText, which was undefined outside secure contexts.
diff --git a/packages/dashboard/app/components/command-center/__tests__/SystemControlsArea.test.tsx b/packages/dashboard/app/components/command-center/__tests__/SystemControlsArea.test.tsx
index 29b922de92..7ceae7ef50 100644
--- a/packages/dashboard/app/components/command-center/__tests__/SystemControlsArea.test.tsx
+++ b/packages/dashboard/app/components/command-center/__tests__/SystemControlsArea.test.tsx
@@ -1,7 +1,7 @@
 import { readFileSync } from "node:fs";
 import { join } from "node:path";
-import { beforeEach, describe, expect, it, vi } from "vitest";
-import { fireEvent, render, screen, waitFor } from "@testing-library/react";
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+import { fireEvent, render, screen, waitFor, within } from "@testing-library/react";
 import "@testing-library/jest-dom";
 import { CommandCenter } from "../CommandCenter";
 
@@ -9,6 +9,7 @@ const apiMock = vi.fn();
 const mockFetchSystemInfo = vi.fn();
 const mockFetchCurrentSystemRebuild = vi.fn();
 const mockFetchSystemStats = vi.fn();
+const mockFetchSystemLogs = vi.fn();
 const mockFetchNodeSystemStats = vi.fn();
 const mockFetchGlobalSettings = vi.fn();
 const mockFetchNodes = vi.fn();
@@ -26,7 +27,7 @@ vi.mock("../../../api/legacy", () => ({
   fetchDashboardHealth: vi.fn().mockResolvedValue({ ok: true }),
   fetchCurrentSystemRebuild: (...args: unknown[]) => mockFetchCurrentSystemRebuild(...args),
   fetchSystemInfo: (...args: unknown[]) => mockFetchSystemInfo(...args),
-  fetchSystemLogs: vi.fn().mockResolvedValue({ entries: [] }),
+  fetchSystemLogs: (...args: unknown[]) => mockFetchSystemLogs(...args),
   reloadAllSystemPlugins: vi.fn().mockResolvedValue({ ok: true }),
   requestSystemRestart: vi.fn().mockResolvedValue({ ok: true }),
   restartAllSystemAgents: vi.fn().mockResolvedValue({ ok: true }),
@@ -114,10 +115,39 @@ function systemStatsFixture() {
 }
 
 describe("SystemControlsArea layout integration", () => {
+  const originalClipboard = navigator.clipboard;
+  const originalExecCommand = document.execCommand;
+
+  function mockClipboard(value: unknown) {
+    Object.defineProperty(navigator, "clipboard", {
+      configurable: true,
+      value,
+    });
+  }
+
+  function mockExecCommand(result: boolean) {
+    const execCommand = vi.fn().mockReturnValue(result);
+    Object.defineProperty(document, "execCommand", {
+      configurable: true,
+      value: execCommand,
+    });
+    return execCommand;
+  }
+
+  async function renderSystemTab(addToast = vi.fn()) {
+    render(<CommandCenter projectId="proj-1" addToast={addToast} />);
+    fireEvent.click(screen.getByTestId("command-center-tab-system"));
+    const diagnosticsCard = await screen.findByTestId("cc-syscontrol-diagnostics");
+    return { addToast, diagnosticsCard };
+  }
+
   beforeEach(() => {
     vi.clearAllMocks();
     apiMock.mockImplementation((path: string) => Promise.resolve(emptyOverviewResponse(path)));
     mockFetchSystemInfo.mockResolvedValue(systemInfoFixture());
+    mockFetchSystemLogs.mockResolvedValue({
+      entries: [{ timestamp: "2026-07-12T00:00:00.000Z", level: "info", message: "ready" }],
+    });
     mockFetchCurrentSystemRebuild.mockResolvedValue({ job: null });
     mockFetchSystemStats.mockResolvedValue(systemStatsFixture());
     mockFetchNodeSystemStats.mockResolvedValue(systemStatsFixture());
@@ -125,6 +155,18 @@ describe("SystemControlsArea layout integration", () => {
     mockFetchNodes.mockResolvedValue([]);
   });
 
+  afterEach(() => {
+    Object.defineProperty(navigator, "clipboard", {
+      configurable: true,
+      value: originalClipboard,
+    });
+    Object.defineProperty(document, "execCommand", {
+      configurable: true,
+      value: originalExecCommand,
+    });
+    document.body.innerHTML = "";
+  });
+
   it("wraps System controls, Server logs, and Live system health in the shared gap owner", async () => {
     render(<CommandCenter projectId="proj-1" />);
 
@@ -162,6 +204,45 @@ describe("SystemControlsArea layout integration", () => {
     expect(refresh.parentElement).toBe(header);
   });
 
+  it("copies diagnostics through the execCommand fallback when Clipboard API is unavailable", async () => {
+    mockClipboard(undefined);
+    const execCommand = mockExecCommand(true);
+    const { addToast, diagnosticsCard } = await renderSystemTab();
+
+    fireEvent.click(within(diagnosticsCard).getByRole("button", { name: "Copy" }));
+
+    await waitFor(() => expect(execCommand).toHaveBeenCalledWith("copy"));
+    expect(addToast).toHaveBeenCalledWith("Diagnostics copied to clipboard", "success");
+    expect(addToast).not.toHaveBeenCalledWith(expect.stringContaining("writeText"), "error");
+  });
+
+  it("copies diagnostics through navigator.clipboard.writeText in secure contexts", async () => {
+    const writeText = vi.fn().mockResolvedValue(undefined);
+    mockClipboard({ writeText });
+    const { addToast, diagnosticsCard } = await renderSystemTab();
+
+    fireEvent.click(within(diagnosticsCard).getByRole("button", { name: "Copy" }));
+
+    await waitFor(() => expect(writeText).toHaveBeenCalledTimes(1));
+    expect(writeText.mock.calls[0]?.[0]).toContain('"recentLogs"');
+    expect(addToast).toHaveBeenCalledWith("Diagnostics copied to clipboard", "success");
+    expect(addToast).not.toHaveBeenCalledWith(expect.stringContaining("writeText"), "error");
+  });
+
+  it("shows a failure toast when diagnostics cannot be copied by either clipboard path", async () => {
+    mockFetchSystemInfo.mockResolvedValue({ ...systemInfoFixture(), logsSupported: false });
+    mockClipboard(undefined);
+    const execCommand = mockExecCommand(false);
+    const { addToast, diagnosticsCard } = await renderSystemTab();
+
+    fireEvent.click(within(diagnosticsCard).getByRole("button", { name: "Copy" }));
+
+    await waitFor(() => expect(execCommand).toHaveBeenCalledWith("copy"));
+    expect(addToast).toHaveBeenCalledWith("Could not copy diagnostics to clipboard", "error");
+    expect(addToast).not.toHaveBeenCalledWith("Diagnostics copied to clipboard", "success");
+    expect(addToast).not.toHaveBeenCalledWith(expect.stringContaining("writeText"), "error");
+  });
+
   it("keeps the System controls header row override active on mobile", () => {
     const css = readFileSync(join(process.cwd(), "app/components/command-center/areas/SystemControlsArea.css"), "utf8");
 
diff --git a/packages/dashboard/app/components/command-center/areas/SystemControlsArea.tsx b/packages/dashboard/app/components/command-center/areas/SystemControlsArea.tsx
index 7c05283d40..ef714402ae 100644
--- a/packages/dashboard/app/components/command-center/areas/SystemControlsArea.tsx
+++ b/packages/dashboard/app/components/command-center/areas/SystemControlsArea.tsx
@@ -31,6 +31,7 @@ import {
 } from "../../../api/legacy";
 import { subscribeSse } from "../../../sse-bus";
 import type { ToastType } from "../../../hooks/useToast";
+import { copyTextToClipboard } from "../../../utils/copyToClipboard";
 import "./SystemControlsArea.css";
 
 /*
@@ -356,8 +357,16 @@ export function SystemControlsArea({ projectId, addToast }: SystemControlsAreaPr
     () =>
       runAction("diagnostics", async () => {
         const diagnostics = await buildDiagnostics();
-        await navigator.clipboard.writeText(JSON.stringify(diagnostics, null, 2));
-        toast(t("systemControls.diagnosticsCopied", "Diagnostics copied to clipboard"), "success");
+        /*
+        FNXC:SystemPanel 2026-07-12-00:00:
+        Diagnostics copy must use copyTextToClipboard because navigator.clipboard is undefined on non-secure origins such as mobile http://fusionstudio:4040. Calling writeText directly previously crashed with reading 'writeText' instead of surfacing a clear copy failure.
+        */
+        const copied = await copyTextToClipboard(JSON.stringify(diagnostics, null, 2));
+        if (copied) {
+          toast(t("systemControls.diagnosticsCopied", "Diagnostics copied to clipboard"), "success");
+          return;
+        }
+        toast(t("systemControls.diagnosticsCopyFailed", "Could not copy diagnostics to clipboard"), "error");
       }),
     [buildDiagnostics, runAction, t, toast],
   );