diff --git a/bin/gstack-update-check b/bin/gstack-update-check
index 7c5e5ca0..d44c7e0f 100755
--- a/bin/gstack-update-check
+++ b/bin/gstack-update-check
@@ -20,6 +20,11 @@ SNOOZE_FILE="$STATE_DIR/update-snoozed"
 VERSION_FILE="$GSTACK_DIR/VERSION"
 REMOTE_URL="${GSTACK_REMOTE_URL:-https://raw.githubusercontent.com/garrytan/gstack/main/VERSION}"
 
+# ─── Force flag (busts cache for standalone /gstack-upgrade) ──
+if [ "${1:-}" = "--force" ]; then
+  rm -f "$CACHE_FILE"
+fi
+
 # ─── Step 0: Check if updates are disabled ────────────────────
 _UC=$("$GSTACK_DIR/bin/gstack-config" get update_check 2>/dev/null || true)
 if [ "$_UC" = "false" ]; then
@@ -97,24 +102,27 @@ if [ -f "$MARKER_FILE" ]; then
   exit 0
 fi
 
-# ─── Step 3: Check cache freshness (12h = 720 min) ──────────
+# ─── Step 3: Check cache freshness ──────────────────────────
+# UP_TO_DATE: 60 min TTL (detect new releases quickly)
+# UPGRADE_AVAILABLE: 720 min TTL (keep nagging)
 if [ -f "$CACHE_FILE" ]; then
-  # Cache is fresh if modified within 720 minutes
-  STALE=$(find "$CACHE_FILE" -mmin +720 2>/dev/null || true)
-  if [ -z "$STALE" ]; then
-    # Cache is fresh — read it
-    CACHED="$(cat "$CACHE_FILE" 2>/dev/null || true)"
+  CACHED="$(cat "$CACHE_FILE" 2>/dev/null || true)"
+  case "$CACHED" in
+    UP_TO_DATE*)        CACHE_TTL=60 ;;
+    UPGRADE_AVAILABLE*) CACHE_TTL=720 ;;
+    *)                  CACHE_TTL=0 ;;  # corrupt → force re-fetch
+  esac
+
+  STALE=$(find "$CACHE_FILE" -mmin +$CACHE_TTL 2>/dev/null || true)
+  if [ -z "$STALE" ] && [ "$CACHE_TTL" -gt 0 ]; then
     case "$CACHED" in
       UP_TO_DATE*)
-        # Verify local version still matches cached version
         CACHED_VER="$(echo "$CACHED" | awk '{print $2}')"
         if [ "$CACHED_VER" = "$LOCAL" ]; then
           exit 0
         fi
-        # Local version changed — fall through to re-check
         ;;
       UPGRADE_AVAILABLE*)
-        # Verify local version still matches cached old version
         CACHED_OLD="$(echo "$CACHED" | awk '{print $2}')"
         if [ "$CACHED_OLD" = "$LOCAL" ]; then
           CACHED_NEW="$(echo "$CACHED" | awk '{print $3}')"
@@ -124,7 +132,6 @@ if [ -f "$CACHE_FILE" ]; then
           echo "$CACHED"
           exit 0
         fi
-        # Local version changed (manual upgrade?) — fall through to re-check
         ;;
     esac
   fi
diff --git a/browse/test/gstack-update-check.test.ts b/browse/test/gstack-update-check.test.ts
index 2ec70e2d..66239931 100644
--- a/browse/test/gstack-update-check.test.ts
+++ b/browse/test/gstack-update-check.test.ts
@@ -7,7 +7,7 @@
  */
 
 import { describe, test, expect, beforeEach, afterEach } from 'bun:test';
-import { mkdtempSync, writeFileSync, rmSync, existsSync, readFileSync, mkdirSync, symlinkSync } from 'fs';
+import { mkdtempSync, writeFileSync, rmSync, existsSync, readFileSync, mkdirSync, symlinkSync, utimesSync } from 'fs';
 import { join } from 'path';
 import { tmpdir } from 'os';
 
@@ -16,8 +16,8 @@ const SCRIPT = join(import.meta.dir, '..', '..', 'bin', 'gstack-update-check');
 let gstackDir: string;
 let stateDir: string;
 
-function run(extraEnv: Record<string, string> = {}) {
-  const result = Bun.spawnSync(['bash', SCRIPT], {
+function run(extraEnv: Record<string, string> = {}, args: string[] = []) {
+  const result = Bun.spawnSync(['bash', SCRIPT, ...args], {
     env: {
       ...process.env,
       GSTACK_DIR: gstackDir,
@@ -412,4 +412,56 @@ describe('gstack-update-check', () => {
     expect(exitCode).toBe(0);
     expect(stdout).toBe('UPGRADE_AVAILABLE 0.3.3 0.4.0');
   });
+
+  // ─── --force flag tests ──────────────────────────────────────
+
+  test('--force busts fresh UP_TO_DATE cache', () => {
+    writeFileSync(join(gstackDir, 'VERSION'), '0.3.3\n');
+    writeFileSync(join(gstackDir, 'REMOTE_VERSION'), '0.4.0\n');
+    writeFileSync(join(stateDir, 'last-update-check'), 'UP_TO_DATE 0.3.3');
+
+    // Without --force: cache hit, silent
+    const cached = run();
+    expect(cached.stdout).toBe('');
+
+    // With --force: cache busted, re-fetches, finds upgrade
+    const forced = run({}, ['--force']);
+    expect(forced.exitCode).toBe(0);
+    expect(forced.stdout).toBe('UPGRADE_AVAILABLE 0.3.3 0.4.0');
+  });
+
+  test('--force busts fresh UPGRADE_AVAILABLE cache', () => {
+    writeFileSync(join(gstackDir, 'VERSION'), '0.3.3\n');
+    writeFileSync(join(gstackDir, 'REMOTE_VERSION'), '0.3.3\n');
+    writeFileSync(join(stateDir, 'last-update-check'), 'UPGRADE_AVAILABLE 0.3.3 0.4.0');
+
+    // Without --force: cache hit, outputs stale upgrade
+    const cached = run();
+    expect(cached.stdout).toBe('UPGRADE_AVAILABLE 0.3.3 0.4.0');
+
+    // With --force: cache busted, re-fetches, now up to date
+    const forced = run({}, ['--force']);
+    expect(forced.exitCode).toBe(0);
+    expect(forced.stdout).toBe('');
+    const cache = readFileSync(join(stateDir, 'last-update-check'), 'utf-8');
+    expect(cache).toContain('UP_TO_DATE');
+  });
+
+  // ─── Split TTL tests ─────────────────────────────────────────
+
+  test('UP_TO_DATE cache expires after 60 min (not 720)', () => {
+    writeFileSync(join(gstackDir, 'VERSION'), '0.3.3\n');
+    writeFileSync(join(gstackDir, 'REMOTE_VERSION'), '0.4.0\n');
+    writeFileSync(join(stateDir, 'last-update-check'), 'UP_TO_DATE 0.3.3');
+
+    // Set cache mtime to 90 minutes ago (past 60-min TTL)
+    const ninetyMinAgo = new Date(Date.now() - 90 * 60 * 1000);
+    const cachePath = join(stateDir, 'last-update-check');
+    utimesSync(cachePath, ninetyMinAgo, ninetyMinAgo);
+
+    // Cache should be stale at 60-min TTL, re-fetches and finds upgrade
+    const { exitCode, stdout } = run();
+    expect(exitCode).toBe(0);
+    expect(stdout).toBe('UPGRADE_AVAILABLE 0.3.3 0.4.0');
+  });
 });