diff --git a/docs/openapi.yaml b/docs/openapi.yaml
index 9dfe25f56e..e33c140dc0 100644
--- a/docs/openapi.yaml
+++ b/docs/openapi.yaml
@@ -1744,6 +1744,16 @@ paths:
         "200":
           description: Provider model list
 
+  /api/providers/cursor/agent-availability:
+    get:
+      tags: [Providers]
+      summary: Check cursor-agent availability
+      description: "Credential-free, informational check for whether cursor-agent is installed and authenticated on this host — backs the dashboard's dismissible install-nudge banner. Returns only cursorAgentAvailable (boolean); never tokens or machineId."
+      x-loopback-only: true
+      responses:
+        "200":
+          description: Availability result
+
   /api/providers/test-batch:
     post:
       tags: [Providers]
diff --git a/src/app/(dashboard)/dashboard/providers/[id]/ProviderDetailPageClient.tsx b/src/app/(dashboard)/dashboard/providers/[id]/ProviderDetailPageClient.tsx
index 95842ad47c..f99309bf07 100644
--- a/src/app/(dashboard)/dashboard/providers/[id]/ProviderDetailPageClient.tsx
+++ b/src/app/(dashboard)/dashboard/providers/[id]/ProviderDetailPageClient.tsx
@@ -49,6 +49,7 @@ import CoolingConnectionsPanel from "./components/CoolingConnectionsPanel";
 import ConnectionsHeaderToolbar from "./components/ConnectionsHeaderToolbar";
 import ProviderAccountRoutingCard from "../../settings/components/ProviderAccountRoutingCard";
 import ZedImportCard from "./components/ZedImportCard";
+import CursorAgentNudge from "./components/CursorAgentNudge";
 import ProviderPageHeader from "./components/ProviderPageHeader";
 import CompatibleNodeCard from "./components/CompatibleNodeCard";
 import ProviderModalsPanel from "./components/ProviderModalsPanel";
@@ -462,6 +463,7 @@ export default function ProviderDetailPageClient() {
       {providerId === "zed" && (
         <ZedImportCard fetchConnections={fetchConnections} notify={notify} />
       )}
+      {providerId === "cursor" && <CursorAgentNudge />}
       {isCompatible && providerNode && (
         <CompatibleNodeCard
           providerId={providerId}
diff --git a/src/app/(dashboard)/dashboard/providers/[id]/components/CursorAgentNudge.tsx b/src/app/(dashboard)/dashboard/providers/[id]/components/CursorAgentNudge.tsx
new file mode 100644
index 0000000000..ee129cee21
--- /dev/null
+++ b/src/app/(dashboard)/dashboard/providers/[id]/components/CursorAgentNudge.tsx
@@ -0,0 +1,102 @@
+"use client";
+
+import { useEffect, useState, useSyncExternalStore } from "react";
+import { useTranslations } from "next-intl";
+
+const DISMISS_STORAGE_KEY = "omniroute.cursorAgentNudgeDismissed";
+// Same-tab signal for the dismiss button, since writing localStorage doesn't
+// fire a "storage" event in the tab that wrote it.
+const DISMISS_EVENT = "omniroute:cursor-agent-nudge-dismissed";
+
+function isNotDismissed(): boolean {
+  try {
+    return !localStorage.getItem(DISMISS_STORAGE_KEY);
+  } catch {
+    return true;
+  }
+}
+
+function subscribe(callback: () => void) {
+  window.addEventListener(DISMISS_EVENT, callback);
+  return () => window.removeEventListener(DISMISS_EVENT, callback);
+}
+
+// SSR has no localStorage, so the server always renders the banner visible;
+// useSyncExternalStore reconciles that against the real client-side value
+// right after hydration, with no hydration mismatch and no setState-in-effect.
+function getServerSnapshot() {
+  return true;
+}
+
+/**
+ * Dismissible dashboard banner suggesting `cursor-agent` installation when
+ * it's not detected on the host — without it, Cursor connections need
+ * periodic manual reconnection roughly every 24 hours instead of automatic
+ * background renewal. Fetches the credential-free, LOCAL_ONLY
+ * `/api/providers/cursor/agent-availability` endpoint — NOT
+ * `/api/oauth/cursor/auto-import`, which returns a live token/machineId and
+ * has no legitimate use here. One global dismissible notice (persisted under
+ * a single fixed key) since this is a host-level, not per-connection, fact.
+ */
+export default function CursorAgentNudge() {
+  const t = useTranslations("providers");
+  const visible = useSyncExternalStore(subscribe, isNotDismissed, getServerSnapshot);
+  const [available, setAvailable] = useState<boolean | null>(null);
+
+  useEffect(() => {
+    let cancelled = false;
+    fetch("/api/providers/cursor/agent-availability")
+      .then((res) => (res.ok ? res.json() : null))
+      .then((data) => {
+        if (!cancelled && data && typeof data.cursorAgentAvailable === "boolean") {
+          setAvailable(data.cursorAgentAvailable);
+        }
+      })
+      .catch(() => {
+        // Unreachable (e.g. a non-loopback dashboard session gets 403
+        // LOCAL_ONLY here) — stay in the "unknown" state rather than nagging
+        // a session that simply can't reach the check.
+      });
+    return () => {
+      cancelled = true;
+    };
+  }, []);
+
+  if (!visible || available !== false) return null;
+
+  const dismiss = () => {
+    try {
+      localStorage.setItem(DISMISS_STORAGE_KEY, "true");
+    } catch {
+      // ignore — worst case the banner reappears next visit
+    }
+    window.dispatchEvent(new Event(DISMISS_EVENT));
+  };
+
+  return (
+    <div
+      role="complementary"
+      aria-label={t("cursorAgentNudgeTitle") || "Enable automatic Cursor session renewal"}
+      className="flex items-start gap-3 rounded-xl border border-blue-500/30 bg-blue-500/5 px-4 py-3"
+    >
+      <span className="material-symbols-outlined text-blue-500 shrink-0 mt-0.5">info</span>
+      <div className="flex-1 min-w-0">
+        <p className="text-sm font-semibold text-blue-700 dark:text-blue-400">
+          {t("cursorAgentNudgeTitle") || "Enable automatic Cursor session renewal"}
+        </p>
+        <p className="text-xs text-blue-600/80 dark:text-blue-300/70 mt-0.5">
+          {t("cursorAgentNudgeBody") ||
+            "Install cursor-agent for automatic session renewal — without it, Cursor connections need periodic manual reconnection roughly every 24 hours."}
+        </p>
+      </div>
+      <button
+        type="button"
+        onClick={dismiss}
+        aria-label={t("cursorAgentNudgeDismiss") || "Dismiss"}
+        className="shrink-0 text-blue-500 hover:text-blue-400 transition-colors"
+      >
+        <span className="material-symbols-outlined text-[18px]">close</span>
+      </button>
+    </div>
+  );
+}
diff --git a/src/app/(dashboard)/dashboard/providers/[id]/components/__tests__/CursorAgentNudge.test.tsx b/src/app/(dashboard)/dashboard/providers/[id]/components/__tests__/CursorAgentNudge.test.tsx
new file mode 100644
index 0000000000..acf3685116
--- /dev/null
+++ b/src/app/(dashboard)/dashboard/providers/[id]/components/__tests__/CursorAgentNudge.test.tsx
@@ -0,0 +1,178 @@
+// @vitest-environment jsdom
+/**
+ * CursorAgentNudge (Cursor renewal plan, Task 5) — dismissible dashboard
+ * banner suggesting `cursor-agent` installation when it's unavailable.
+ * Mirrors tests/unit/ui/kimiSponsorBanner.test.tsx's technique for the same
+ * useSyncExternalStore + localStorage dismissal pattern (KimiSponsorBanner.tsx
+ * is the precedent this component follows), and this directory's own
+ * __tests__/phase1d.test.tsx for the createRoot/act mounting convention.
+ */
+import React from "react";
+import { act } from "react";
+import { createRoot, hydrateRoot } from "react-dom/client";
+import { renderToString } from "react-dom/server";
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+import CursorAgentNudge from "../CursorAgentNudge";
+
+const STORAGE_KEY = "omniroute.cursorAgentNudgeDismissed";
+
+vi.mock("next-intl", () => ({ useTranslations: () => (k: string) => k }));
+
+function mockFetch(cursorAgentAvailable: boolean | null) {
+  return vi.fn(async (url: string) => {
+    if (cursorAgentAvailable === null) {
+      return { ok: false, json: async () => ({}) } as Response;
+    }
+    return { ok: true, json: async () => ({ cursorAgentAvailable }) } as Response;
+  });
+}
+
+async function flushEffects() {
+  await act(async () => {
+    await new Promise((resolve) => setTimeout(resolve, 0));
+  });
+}
+
+function renderNudge(): HTMLDivElement {
+  const container = document.createElement("div");
+  document.body.appendChild(container);
+  const root = createRoot(container);
+  act(() => {
+    root.render(<CursorAgentNudge />);
+  });
+  return container;
+}
+
+describe("CursorAgentNudge", () => {
+  beforeEach(() => {
+    (
+      globalThis as typeof globalThis & { IS_REACT_ACT_ENVIRONMENT?: boolean }
+    ).IS_REACT_ACT_ENVIRONMENT = true;
+    localStorage.removeItem(STORAGE_KEY);
+  });
+
+  afterEach(() => {
+    document.body.innerHTML = "";
+    localStorage.removeItem(STORAGE_KEY);
+    vi.unstubAllGlobals();
+  });
+
+  it("renders when cursorAgentAvailable is false", async () => {
+    vi.stubGlobal("fetch", mockFetch(false));
+    const container = renderNudge();
+    await flushEffects();
+
+    expect(container.querySelector("[role='complementary']")).not.toBeNull();
+  });
+
+  it("does not render when cursorAgentAvailable is true", async () => {
+    vi.stubGlobal("fetch", mockFetch(true));
+    const container = renderNudge();
+    await flushEffects();
+
+    expect(container.querySelector("[role='complementary']")).toBeNull();
+  });
+
+  it("does not render while the availability check is still pending or unreachable", async () => {
+    vi.stubGlobal("fetch", mockFetch(null)); // res.ok === false -> stays in the "unknown" state
+    const container = renderNudge();
+    await flushEffects();
+
+    expect(container.querySelector("[role='complementary']")).toBeNull();
+  });
+
+  it("fetches /api/providers/cursor/agent-availability, NOT /api/oauth/cursor/auto-import", async () => {
+    const fetchMock = mockFetch(false);
+    vi.stubGlobal("fetch", fetchMock);
+    renderNudge();
+    await flushEffects();
+
+    expect(fetchMock).toHaveBeenCalledWith("/api/providers/cursor/agent-availability");
+    for (const call of fetchMock.mock.calls) {
+      expect(String(call[0])).not.toContain("/api/oauth/cursor/auto-import");
+    }
+  });
+
+  it("dismiss button hides the banner and persists the dismissal to localStorage", async () => {
+    vi.stubGlobal("fetch", mockFetch(false));
+    const container = renderNudge();
+    await flushEffects();
+    expect(container.querySelector("[role='complementary']")).not.toBeNull();
+
+    const dismissButton = container.querySelector("button");
+    expect(dismissButton).not.toBeNull();
+    act(() => {
+      dismissButton?.dispatchEvent(new MouseEvent("click", { bubbles: true }));
+    });
+
+    expect(container.querySelector("[role='complementary']")).toBeNull();
+    expect(localStorage.getItem(STORAGE_KEY)).toBe("true");
+  });
+
+  it("stays hidden across a fresh render once dismissed (localStorage persistence — no reappear)", async () => {
+    localStorage.setItem(STORAGE_KEY, "true");
+    vi.stubGlobal("fetch", mockFetch(false)); // still "unavailable" — dismissal alone must suppress it
+    const container = renderNudge();
+    await flushEffects();
+
+    expect(container.querySelector("[role='complementary']")).toBeNull();
+  });
+
+  it("stays hidden after an actual unmount+remount of the same dismissed state", async () => {
+    vi.stubGlobal("fetch", mockFetch(false));
+    const first = document.createElement("div");
+    document.body.appendChild(first);
+    const firstRoot = createRoot(first);
+    act(() => {
+      firstRoot.render(<CursorAgentNudge />);
+    });
+    await act(async () => {
+      await new Promise((resolve) => setTimeout(resolve, 0));
+    });
+    const dismissButton = first.querySelector("button");
+    act(() => {
+      dismissButton?.dispatchEvent(new MouseEvent("click", { bubbles: true }));
+    });
+    act(() => {
+      firstRoot.unmount();
+    });
+    first.remove();
+
+    const second = renderNudge();
+    await flushEffects();
+    expect(second.querySelector("[role='complementary']")).toBeNull();
+  });
+
+  it("hydrates without a mismatch warning (SSR always renders nothing before the fetch resolves)", async () => {
+    vi.stubGlobal("fetch", mockFetch(false));
+
+    const serverHtml = renderToString(<CursorAgentNudge />);
+    // The component renders null on the server (available starts at null,
+    // getServerSnapshot() returns true but `available !== false` short-circuits
+    // the render to null regardless) — this proves that invariant holds.
+    expect(serverHtml).toBe("");
+
+    const container = document.createElement("div");
+    container.innerHTML = serverHtml;
+    document.body.appendChild(container);
+
+    const errors: unknown[][] = [];
+    const originalConsoleError = console.error;
+    console.error = (...args: unknown[]) => {
+      errors.push(args);
+    };
+
+    try {
+      act(() => {
+        hydrateRoot(container, <CursorAgentNudge />);
+      });
+    } finally {
+      console.error = originalConsoleError;
+    }
+
+    const hydrationWarnings = errors.filter((args) =>
+      args.some((a) => typeof a === "string" && /hydrat/i.test(a))
+    );
+    expect(hydrationWarnings).toEqual([]);
+  });
+});
diff --git a/src/app/api/providers/cursor/agent-availability/route.ts b/src/app/api/providers/cursor/agent-availability/route.ts
new file mode 100644
index 0000000000..bac93446f1
--- /dev/null
+++ b/src/app/api/providers/cursor/agent-availability/route.ts
@@ -0,0 +1,31 @@
+import { NextResponse } from "next/server";
+import { getCachedCursorAgentAvailability } from "@/lib/cursor/renewal";
+
+/**
+ * GET /api/providers/cursor/agent-availability
+ * Credential-free, informational check for whether `cursor-agent` is
+ * installed and authenticated on this host — backs the dashboard's
+ * dismissible install-nudge banner. Returns ONLY `{ cursorAgentAvailable }`;
+ * never tokens/machineId. This is a SEPARATE route from
+ * `/api/oauth/cursor/auto-import` (which legitimately returns
+ * `accessToken`/`machineId` for its own credential-import purpose) —
+ * reusing that route here would hand a live local Cursor OAuth token to a
+ * frequently-mounted, purely informational UI component with no legitimate
+ * use for it.
+ *
+ * No in-route auth guard: unlike `/api/oauth/cursor/auto-import` (which is
+ * PUBLIC-classified and never reaches the LOCAL_ONLY gate), this route lives
+ * under `/api/providers/` — MANAGEMENT-classified — and is itself
+ * LOCAL_ONLY (see `LOCAL_ONLY_API_PREFIXES` in
+ * `src/server/authz/routeGuard.ts`), so `managementPolicy` already enforces
+ * auth + loopback before this handler runs, matching the sibling
+ * `/api/providers/[id]/refresh` and `/api/providers/[id]/login` routes
+ * (neither perform their own in-route auth check either).
+ *
+ * 🔒 LOCAL_ONLY — spawns `cursor-agent status --format json` via
+ * `checkCursorAgentAvailability()` (Hard Rules #15 + #17).
+ */
+export async function GET() {
+  const { available } = await getCachedCursorAgentAvailability();
+  return NextResponse.json({ cursorAgentAvailable: available });
+}
diff --git a/src/i18n/messages/en.json b/src/i18n/messages/en.json
index 62d6c4719b..0fd7adab01 100644
--- a/src/i18n/messages/en.json
+++ b/src/i18n/messages/en.json
@@ -5637,6 +5637,9 @@
     "zedPasteApiKey": "Paste API key…",
     "zedSaving": "Saving…",
     "zedImportAction": "Import",
+    "cursorAgentNudgeTitle": "Enable automatic Cursor session renewal",
+    "cursorAgentNudgeBody": "Install cursor-agent for automatic session renewal — without it, Cursor connections need periodic manual reconnection roughly every 24 hours.",
+    "cursorAgentNudgeDismiss": "Dismiss",
     "zedManualImportFailed": "Manual import failed",
     "zedManualImportSuccess": "Imported {provider} token from Zed",
     "grokImportTitle": "Import Grok Build Auth",
diff --git a/src/lib/cursor/renewal.ts b/src/lib/cursor/renewal.ts
index e7736edf71..5338cf7938 100644
--- a/src/lib/cursor/renewal.ts
+++ b/src/lib/cursor/renewal.ts
@@ -103,6 +103,34 @@ export async function checkCursorAgentAvailability(): Promise<{
   }
 }
 
+const CURSOR_AGENT_AVAILABILITY_CACHE_TTL_MS = 5 * 60 * 1000;
+
+let cachedAvailability: {
+  result: { available: boolean; binaryPath: string | null };
+  expiresAt: number;
+} | null = null;
+
+/**
+ * Cached wrapper around checkCursorAgentAvailability(), for INFORMATIONAL/UI
+ * callers only (5-minute TTL) — e.g. the dashboard's install-nudge banner,
+ * which may mount/refetch frequently. Task 3's sweep and Task 4's manual
+ * refresh route continue calling the UNCACHED checkCursorAgentAvailability()
+ * directly: a "refresh now" click must always see a fresh status, never a
+ * stale cached answer.
+ */
+export async function getCachedCursorAgentAvailability(): Promise<{
+  available: boolean;
+  binaryPath: string | null;
+}> {
+  const now = Date.now();
+  if (cachedAvailability && cachedAvailability.expiresAt > now) {
+    return cachedAvailability.result;
+  }
+  const result = await checkCursorAgentAvailability();
+  cachedAvailability = { result, expiresAt: now + CURSOR_AGENT_AVAILABILITY_CACHE_TTL_MS };
+  return result;
+}
+
 export type CursorRenewalResult =
   | {
       status: "renewed";
diff --git a/src/server/authz/routeGuard.ts b/src/server/authz/routeGuard.ts
index f4381b24f7..f1e04efa64 100644
--- a/src/server/authz/routeGuard.ts
+++ b/src/server/authz/routeGuard.ts
@@ -53,11 +53,12 @@ export const LOCAL_ONLY_API_PREFIXES: ReadonlyArray<string> = [
   "/api/local/", // T-12: 1-click local service launchers (Redis today; spawns podman/docker) — loopback-enforced by isLocalRequestAllowed() in src/lib/security/localEndpoints.ts (Hard Rules #15 + #17)
   "/api/headroom/start", // Headroom token-saver proxy lifecycle: spawns headroom-ai python CLI (Hard Rules #15 + #17)
   "/api/headroom/stop", // Headroom token-saver proxy lifecycle: sends SIGTERM/SIGKILL to managed PID (Hard Rules #15 + #17)
-  "/api/oauth/cursor/auto-import", // spawns `execFile("which", ["cursor"])` to verify a local Cursor install before importing creds — RCE-via-tunnel surface (Hard Rules #15 + #17, found by 6A.8 route-guard gate). Specific path only: the rest of /api/oauth/ (browser redirect/callback flows) must stay remote-reachable.
+  "/api/oauth/cursor/auto-import", // spawns `execFile("which", "cursor")` to verify a local Cursor install before importing creds — RCE-via-tunnel surface (Hard Rules #15 + #17, found by 6A.8 route-guard gate). Specific path only: the rest of /api/oauth/ (browser redirect/callback flows) must stay remote-reachable.
   "/api/skills/collect/", // Skill Collector CLI detection: GET .../detect probes getCliRuntimeStatus() per CLI_TOOL_IDS entry, which spawns a child process to check each tool — RCE-via-tunnel surface (Hard Rules #15 + #17, PR #6294 review).
   "/api/discovery/", // Discovery tool (opt-in provider scanner): the scan route makes outbound probes to provider endpoints (SSRF-adjacent) and the whole surface is an admin research tool — strict-loopback only, no manage-scope bypass (NOT in LOCAL_ONLY_MANAGE_SCOPE_BYPASS_PREFIXES). See _tasks/features-v3.8.42/gaps/DISCOVERY_TOOL_DESIGN.md.
   VNC_ROUTE_PREFIX, // #7892: /api/vnc-session/* spawns Docker containers via child_process.spawn (src/lib/vncSession/service.ts) — RCE-via-tunnel surface (Hard Rules #15 + #17), same CVE class (GHSA-fhh6-4qxv-rpqj).
   "/api/acp/agents", // ACP custom-agent registry: POST registers a client-chosen `binary`; GET / POST {action:"refresh"} runs detectInstalledAgents() -> execFileSync(probe.command, probe.args, { shell }) transitively (src/lib/acp/registry.ts) — RCE-via-tunnel surface (Hard Rules #15 + #17, #7948)
+  "/api/providers/cursor/agent-availability", // credential-free dashboard-nudge check: spawns `cursor-agent status --format json` via checkCursorAgentAvailability()/getCachedCursorAgentAvailability() (src/lib/cursor/renewal.ts) — RCE-via-tunnel surface (Hard Rules #15 + #17). Narrow-scoped like /login and /refresh-cursor, not the whole /api/providers/ tree. Placed under /api/providers/ rather than /api/oauth/ because /api/oauth/ is PUBLIC-classified and never reaches this LOCAL_ONLY gate.
 ];
 
 /**
diff --git a/src/shared/constants/spawnCapablePrefixes.ts b/src/shared/constants/spawnCapablePrefixes.ts
index 5357cef34c..e1e285ea0e 100644
--- a/src/shared/constants/spawnCapablePrefixes.ts
+++ b/src/shared/constants/spawnCapablePrefixes.ts
@@ -50,6 +50,7 @@ export const SPAWN_CAPABLE_PREFIXES: ReadonlyArray<string> = [
 export const SPAWN_CAPABLE_PATTERNS: ReadonlyArray<RegExp> = [
   /^\/api\/providers\/[^/]+\/login\/?$/, // pre-existing gap: in LOCAL_ONLY_API_PATTERNS today but never in a spawn-capable deny-list
   /^\/api\/providers\/[^/]+\/refresh-cursor\/?$/, // spawns cursor-agent via renewal.ts (Hard Rules #15 + #17)
+  /^\/api\/providers\/cursor\/agent-availability\/?$/, // static path (no dynamic segment), but kept in this array alongside its /api/providers/ siblings rather than the flat SPAWN_CAPABLE_PREFIXES array — spawns cursor-agent status via checkCursorAgentAvailability()/getCachedCursorAgentAvailability() (Hard Rules #15 + #17)
 ];
 
 /**
diff --git a/tests/unit/cursor-agent-availability-route-authenticated.test.ts b/tests/unit/cursor-agent-availability-route-authenticated.test.ts
new file mode 100644
index 0000000000..1959910495
--- /dev/null
+++ b/tests/unit/cursor-agent-availability-route-authenticated.test.ts
@@ -0,0 +1,61 @@
+/**
+ * GET /api/providers/cursor/agent-availability — "authenticated -> true" case.
+ * Split from tests/unit/cursor-agent-availability-route.test.ts (its own
+ * process, so its own fresh getCachedCursorAgentAvailability() module cache —
+ * see that file's header comment for why the true/false cases can't share a
+ * process).
+ */
+import test from "node:test";
+import assert from "node:assert/strict";
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
+
+process.env.NODE_ENV = "test";
+const TEST_DATA_DIR = fs.mkdtempSync(
+  path.join(os.tmpdir(), "omniroute-agent-availability-route-auth-")
+);
+process.env.DATA_DIR = TEST_DATA_DIR;
+
+const core = await import("../../src/lib/db/core.ts");
+const { GET } = await import("../../src/app/api/providers/cursor/agent-availability/route.ts");
+
+test.after(() => {
+  core.resetDbInstance();
+  fs.rmSync(TEST_DATA_DIR, { recursive: true, force: true });
+});
+
+const FAKE_CURSOR_AGENT_SCRIPT = `#!/usr/bin/env node
+const args = process.argv.slice(2);
+if (args[0] === "status") {
+  process.stdout.write(JSON.stringify({ status: "authenticated", isAuthenticated: true }));
+}
+`;
+
+const originalHome = process.env.HOME;
+const originalUserProfile = process.env.USERPROFILE;
+const tmpHome = fs.mkdtempSync(path.join(os.tmpdir(), "omniroute-agent-availability-home-auth-"));
+process.env.HOME = tmpHome;
+process.env.USERPROFILE = tmpHome;
+const binaryPath = path.join(tmpHome, ".local", "bin", "cursor-agent");
+fs.mkdirSync(path.dirname(binaryPath), { recursive: true });
+fs.writeFileSync(binaryPath, FAKE_CURSOR_AGENT_SCRIPT, { mode: 0o755 });
+fs.chmodSync(binaryPath, 0o755);
+
+test.after(() => {
+  process.env.HOME = originalHome;
+  if (originalUserProfile !== undefined) process.env.USERPROFILE = originalUserProfile;
+  else delete process.env.USERPROFILE;
+  fs.rmSync(tmpHome, { recursive: true, force: true });
+});
+
+test("returns {cursorAgentAvailable: true} and ONLY that field when cursor-agent is authenticated", async () => {
+  const res = await GET();
+  const body = (await res.json()) as Record<string, unknown>;
+
+  assert.equal(res.status, 200);
+  assert.deepEqual(Object.keys(body), ["cursorAgentAvailable"]);
+  assert.equal(body.cursorAgentAvailable, true);
+  assert.equal(body.accessToken, undefined);
+  assert.equal(body.machineId, undefined);
+});
diff --git a/tests/unit/cursor-agent-availability-route.test.ts b/tests/unit/cursor-agent-availability-route.test.ts
new file mode 100644
index 0000000000..c395a228d9
--- /dev/null
+++ b/tests/unit/cursor-agent-availability-route.test.ts
@@ -0,0 +1,116 @@
+/**
+ * GET /api/providers/cursor/agent-availability (Cursor renewal plan, Task 5).
+ *
+ * Real fake-cursor-agent-binary + HOME-override technique (see
+ * tests/unit/cursor-renewal.test.ts) to drive getCachedCursorAgentAvailability()
+ * for real — no mocking, same rationale as every other Cursor test file in
+ * this plan (no DI seam, no mock.module() support in this harness).
+ *
+ * getCachedCursorAgentAvailability() has a module-level 5-minute TTL cache
+ * with no exported reset hook, so this file only exercises ONE truth value
+ * through the live route (the "unauthenticated" default state a fresh test
+ * fixture naturally has) — a second call within the same process would
+ * silently replay the FIRST call's cached result regardless of a changed
+ * fixture, which would look like a passing assertion for the wrong reason.
+ * The "authenticated -> true" mapping is verified in a separate file
+ * (tests/unit/cursor-agent-availability-route-authenticated.test.ts, its own
+ * process, so its own fresh cache) — the TTL cache's own behavior (reuse
+ * within the window, fresh spawn after expiry) is covered directly in
+ * tests/unit/cursor-renewal.test.ts.
+ *
+ * DATA_DIR is overridden to a temp dir BEFORE any import below, since loading
+ * src/server/authz/policies/management.ts transitively touches the real DB
+ * singleton at import time.
+ */
+import test from "node:test";
+import assert from "node:assert/strict";
+import fs from "node:fs";
+import os from "node:os";
+import path from "node:path";
+
+process.env.NODE_ENV = "test";
+const TEST_DATA_DIR = fs.mkdtempSync(path.join(os.tmpdir(), "omniroute-agent-availability-route-"));
+process.env.DATA_DIR = TEST_DATA_DIR;
+
+const core = await import("../../src/lib/db/core.ts");
+const { GET } = await import("../../src/app/api/providers/cursor/agent-availability/route.ts");
+const { managementPolicy } = await import("../../src/server/authz/policies/management.ts");
+
+const FAKE_CURSOR_AGENT_SCRIPT = `#!/usr/bin/env node
+const args = process.argv.slice(2);
+if (args[0] === "status") {
+  const mode = process.env.FAKE_CURSOR_AGENT_STATUS_MODE || "unauthenticated";
+  if (mode === "authenticated") {
+    process.stdout.write(JSON.stringify({ status: "authenticated", isAuthenticated: true }));
+  } else {
+    process.stdout.write(JSON.stringify({ status: "unauthenticated", isAuthenticated: false }));
+  }
+}
+`;
+
+test.after(() => {
+  core.resetDbInstance();
+  fs.rmSync(TEST_DATA_DIR, { recursive: true, force: true });
+});
+
+function writeFakeCursorAgentBinary(destPath: string): void {
+  fs.mkdirSync(path.dirname(destPath), { recursive: true });
+  fs.writeFileSync(destPath, FAKE_CURSOR_AGENT_SCRIPT, { mode: 0o755 });
+  fs.chmodSync(destPath, 0o755);
+}
+
+const originalHome = process.env.HOME;
+const originalUserProfile = process.env.USERPROFILE;
+const tmpHome = fs.mkdtempSync(path.join(os.tmpdir(), "omniroute-agent-availability-home-"));
+process.env.HOME = tmpHome;
+process.env.USERPROFILE = tmpHome;
+process.env.FAKE_CURSOR_AGENT_STATUS_MODE = "unauthenticated";
+writeFakeCursorAgentBinary(path.join(tmpHome, ".local", "bin", "cursor-agent"));
+
+test.after(() => {
+  process.env.HOME = originalHome;
+  if (originalUserProfile !== undefined) process.env.USERPROFILE = originalUserProfile;
+  else delete process.env.USERPROFILE;
+  delete process.env.FAKE_CURSOR_AGENT_STATUS_MODE;
+  fs.rmSync(tmpHome, { recursive: true, force: true });
+});
+
+test("returns {cursorAgentAvailable: false} and ONLY that field when cursor-agent is unauthenticated", async () => {
+  const res = await GET();
+  const body = (await res.json()) as Record<string, unknown>;
+
+  assert.equal(res.status, 200);
+  assert.deepEqual(Object.keys(body), ["cursorAgentAvailable"]);
+  assert.equal(body.cursorAgentAvailable, false);
+  assert.equal(body.accessToken, undefined);
+  assert.equal(body.machineId, undefined);
+});
+
+// Loopback enforcement happens unconditionally before any auth check (Hard
+// Rules #15 + #17): a non-loopback caller with NO credentials at all must
+// still be rejected by the managementPolicy pipeline itself — never by an
+// in-route check (this route intentionally has none; see route.ts's own
+// comment on why).
+test("a non-loopback, unauthenticated request is rejected by managementPolicy (403 LOCAL_ONLY), not by the route", async () => {
+  const requestPath = "/api/providers/cursor/agent-availability";
+  const outcome = await managementPolicy.evaluate({
+    request: {
+      method: "GET",
+      headers: new Headers(),
+      url: `https://dashboard.example${requestPath}`,
+      nextUrl: { pathname: requestPath },
+    },
+    classification: {
+      routeClass: "MANAGEMENT",
+      normalizedPath: requestPath,
+      reason: "management_api",
+    },
+    requestId: "req_cursor_agent_availability_test",
+  } as unknown as Parameters<typeof managementPolicy.evaluate>[0]);
+
+  assert.equal(outcome.allow, false);
+  if (!outcome.allow) {
+    assert.equal(outcome.status, 403);
+    assert.equal(outcome.code, "LOCAL_ONLY");
+  }
+});
diff --git a/tests/unit/cursor-renewal.test.ts b/tests/unit/cursor-renewal.test.ts
index dd54633ec9..0d206826c1 100644
--- a/tests/unit/cursor-renewal.test.ts
+++ b/tests/unit/cursor-renewal.test.ts
@@ -29,6 +29,7 @@ import path from "node:path";
 import {
   runCursorAgentNudge,
   checkCursorAgentAvailability,
+  getCachedCursorAgentAvailability,
   renewCursorConnection,
   buildCursorRenewedUpdate,
   runCursorRenewalExclusive,
@@ -262,6 +263,63 @@ describe("checkCursorAgentAvailability", () => {
   });
 });
 
+describe("getCachedCursorAgentAvailability (Task 5 Step 1 — 5-minute TTL wrapper for UI callers)", () => {
+  const ORIGINAL_HOME = process.env.HOME;
+  const ORIGINAL_USERPROFILE = process.env.USERPROFILE;
+  const CACHE_TTL_MS = 5 * 60 * 1000; // mirrors CURSOR_AGENT_AVAILABILITY_CACHE_TTL_MS in renewal.ts
+  let tmpHome: string;
+  let logPath: string;
+
+  beforeEach(() => {
+    tmpHome = fs.mkdtempSync(path.join(os.tmpdir(), "omniroute-cursor-avail-cache-"));
+    process.env.HOME = tmpHome;
+    process.env.USERPROFILE = tmpHome;
+    writeFakeCursorAgentBinary(path.join(tmpHome, ".local", "bin", "cursor-agent"));
+    logPath = path.join(tmpHome, "log.jsonl");
+    process.env.FAKE_CURSOR_AGENT_LOG = logPath;
+    process.env.FAKE_CURSOR_AGENT_STATUS_MODE = "authenticated";
+  });
+
+  afterEach(() => {
+    process.env.HOME = ORIGINAL_HOME;
+    if (ORIGINAL_USERPROFILE !== undefined) process.env.USERPROFILE = ORIGINAL_USERPROFILE;
+    else delete process.env.USERPROFILE;
+    clearFakeCursorAgentEnv();
+    fs.rmSync(tmpHome, { recursive: true, force: true });
+  });
+
+  // A single test, one continuous mocked timeline: getCachedCursorAgentAvailability()'s
+  // module-level cache has no exported reset hook and persists for the life of the
+  // process, so two separate `it()` blocks each assuming a "fresh" cache would be
+  // order-dependent (a later test could silently inherit an earlier test's still-valid
+  // cache entry, since node:test's per-test mock-timer teardown restores the REAL clock
+  // between tests, not the fake one — the leftover `expiresAt` would still be far in
+  // that real future). Keeping both assertions on one uninterrupted fake clock avoids that.
+  it("reuses the cached result within the TTL window, then spawns exactly once more after it expires", async (t) => {
+    t.mock.timers.enable({ apis: ["Date"] });
+
+    const first = await getCachedCursorAgentAvailability();
+    assert.equal(readLoggedInvocations(logPath).length, 1, "the first call must spawn");
+
+    t.mock.timers.tick(CACHE_TTL_MS - 1000); // still inside the window
+    const second = await getCachedCursorAgentAvailability();
+    assert.deepEqual(first, second);
+    assert.equal(
+      readLoggedInvocations(logPath).length,
+      1,
+      "still within the TTL — no second spawn"
+    );
+
+    t.mock.timers.tick(2000); // now past the TTL (cumulative: TTL + 1000ms)
+    await getCachedCursorAgentAvailability();
+    assert.equal(
+      readLoggedInvocations(logPath).length,
+      2,
+      "expiry must trigger exactly one fresh spawn"
+    );
+  });
+});
+
 describe("renewCursorConnection", () => {
   const ORIGINAL_HOME = process.env.HOME;
   const ORIGINAL_USERPROFILE = process.env.USERPROFILE;
diff --git a/tests/unit/route-guard-cursor-agent-availability.test.ts b/tests/unit/route-guard-cursor-agent-availability.test.ts
new file mode 100644
index 0000000000..bec0dc0fe2
--- /dev/null
+++ b/tests/unit/route-guard-cursor-agent-availability.test.ts
@@ -0,0 +1,49 @@
+/**
+ * Security regression (Cursor renewal plan, Task 5): GET
+ * /api/providers/cursor/agent-availability is a credential-free check for the
+ * dashboard's install-nudge banner, but it still spawns `cursor-agent status
+ * --format json` (via checkCursorAgentAvailability()/
+ * getCachedCursorAgentAvailability()) — so it MUST be LOCAL_ONLY, same as
+ * every other spawn-capable route (Hard Rules #15 + #17).
+ *
+ * Unlike Task 4's refresh-cursor route, this one is a STATIC path (no dynamic
+ * `[id]` segment), so it's classified via the flat LOCAL_ONLY_API_PREFIXES
+ * list, not a regex in LOCAL_ONLY_API_PATTERNS. It was originally scoped
+ * under `/api/oauth/cursor/agent-availability` during planning, then
+ * relocated under `/api/providers/` because `/api/oauth/` is PUBLIC-classified
+ * (see classify.ts) and never reaches the LOCAL_ONLY gate at all — see
+ * docs/security/ROUTE_GUARD_TIERS.md. The classifyRoute assertion below pins
+ * that decision as a regression guard against ever moving this back.
+ */
+import test from "node:test";
+import assert from "node:assert/strict";
+import { isLocalOnlyPath } from "../../src/server/authz/routeGuard.ts";
+import { classifyRoute } from "../../src/server/authz/classify.ts";
+
+test("/api/providers/cursor/agent-availability is LOCAL_ONLY (spawns cursor-agent status)", () => {
+  assert.equal(isLocalOnlyPath("/api/providers/cursor/agent-availability"), true);
+});
+
+test("/api/providers/cursor/agent-availability with a trailing slash is LOCAL_ONLY", () => {
+  assert.equal(isLocalOnlyPath("/api/providers/cursor/agent-availability/"), true);
+});
+
+test("classifyRoute resolves this path to MANAGEMENT, never PUBLIC (regression guard against moving it under /api/oauth/)", () => {
+  const classification = classifyRoute("/api/providers/cursor/agent-availability", "GET");
+  assert.equal(classification.routeClass, "MANAGEMENT");
+});
+
+test("does not over-match unrelated /api/providers paths", () => {
+  // LOCAL_ONLY_API_PREFIXES entries are matched via plain startsWith (see
+  // isLocalOnlyPath) — like every other exact-path-style sibling entry in
+  // that array (e.g. /api/system/version, /api/oauth/cursor/auto-import,
+  // /api/acp/agents), this is a bare path with no trailing slash, so it is
+  // NOT segment-boundary-anchored the way the regex-based /login and
+  // /refresh-cursor entries in LOCAL_ONLY_API_PATTERNS are (see
+  // tests/unit/route-guard-cursor-refresh.test.ts). Only paths that don't
+  // share the prefix at all are meaningful negative cases here.
+  assert.equal(isLocalOnlyPath("/api/providers"), false);
+  assert.equal(isLocalOnlyPath("/api/providers/"), false);
+  assert.equal(isLocalOnlyPath("/api/providers/cursor"), false);
+  assert.equal(isLocalOnlyPath("/api/providers/abc123/refresh"), false);
+});