diff --git a/hermes_cli/config.py b/hermes_cli/config.py
index f36b788bbf5..3cd901c803e 100644
--- a/hermes_cli/config.py
+++ b/hermes_cli/config.py
@@ -2952,6 +2952,11 @@ DEFAULT_CONFIG = {
         #               ignored paths — node_modules, venv, build outputs —
         #               are never touched.
         "non_interactive_local_changes": "stash",
+        # Refresh an already-installed cua-driver during `hermes update`.
+        # The refresh is best-effort and macOS-only. Turn this off if the
+        # upstream installer is not appropriate for the machine, for example
+        # on non-admin accounts where `/Applications` is not writable.
+        "refresh_cua_driver": True,
     },
 
     # Language Server Protocol — semantic diagnostics from real
diff --git a/hermes_cli/main.py b/hermes_cli/main.py
index 4e483d318c3..a4a4c39f597 100644
--- a/hermes_cli/main.py
+++ b/hermes_cli/main.py
@@ -10243,7 +10243,23 @@ def _cmd_update_impl(args, gateway_mode: bool):
         # predictable cadence (matches when they pull new agent code) without
         # adding startup latency or a per-launch GitHub API call.
         try:
-            if sys.platform in ("darwin", "win32", "linux") and shutil.which("cua-driver"):
+            refresh_cua_driver = True
+            try:
+                from hermes_cli.config import load_config
+
+                _update_cfg = (load_config() or {}).get("updates", {})
+                if isinstance(_update_cfg, dict):
+                    refresh_cua_driver = bool(
+                        _update_cfg.get("refresh_cua_driver", True)
+                    )
+            except Exception as cfg_exc:
+                logger.debug("Could not read updates.refresh_cua_driver: %s", cfg_exc)
+
+            if (
+                refresh_cua_driver
+                and sys.platform in ("darwin", "win32", "linux")
+                and shutil.which("cua-driver")
+            ):
                 from hermes_cli.tools_config import install_cua_driver
 
                 print()
diff --git a/hermes_cli/tools_config.py b/hermes_cli/tools_config.py
index eba4e4c0b67..047c2abe223 100644
--- a/hermes_cli/tools_config.py
+++ b/hermes_cli/tools_config.py
@@ -705,6 +705,19 @@ def _pip_install(
 # no Python-side duplication.
 
 
+def _cua_install_target_writable() -> bool:
+    """Return whether the upstream installer can write its app bundle target."""
+    if sys.platform != "darwin":
+        return True
+    applications_dir = "/Applications"
+    try:
+        if not os.path.isdir(applications_dir):
+            return True
+        return os.access(applications_dir, os.W_OK)
+    except Exception:
+        return True
+
+
 def install_cua_driver(upgrade: bool = False) -> bool:
     """Install or refresh the cua-driver binary used by Computer Use.
 
@@ -747,6 +760,14 @@ def install_cua_driver(upgrade: bool = False) -> bool:
 
     # Not installed → fresh install path (only when caller asked for it).
     if not binary and not upgrade:
+        if not _cua_install_target_writable():
+            _print_info(
+                "    /Applications is not writable; skipping cua-driver install."
+            )
+            _print_info(
+                "    Run from an admin account or install cua-driver manually."
+            )
+            return False
         if not shutil.which(fetch_tool):
             _print_warning(f"    {fetch_tool} not found — install manually:")
             _print_info("      https://github.com/trycua/cua/blob/main/libs/cua-driver/README.md")
@@ -778,6 +799,15 @@ def install_cua_driver(upgrade: bool = False) -> bool:
         return True
 
     # upgrade=True path — refresh to the latest upstream release.
+    if not _cua_install_target_writable():
+        _print_info(
+            "    /Applications is not writable; skipping cua-driver refresh."
+        )
+        _print_info(
+            "    Run `hermes computer-use install --upgrade` from an admin account to update it."
+        )
+        return bool(binary)
+
     if not shutil.which(fetch_tool):
         _print_warning(f"    {fetch_tool} not found — cannot refresh cua-driver.")
         return bool(binary)
diff --git a/hermes_cli/web_server.py b/hermes_cli/web_server.py
index 26f35fce384..45e5d7b8496 100644
--- a/hermes_cli/web_server.py
+++ b/hermes_cli/web_server.py
@@ -708,6 +708,14 @@ _SCHEMA_OVERRIDES: Dict[str, Dict[str, Any]] = {
         ),
         "options": ["stash", "discard"],
     },
+    "updates.refresh_cua_driver": {
+        "type": "bool",
+        "description": (
+            "Refresh an already-installed cua-driver during hermes update. "
+            "Disable this on non-admin macOS accounts where /Applications is "
+            "not writable."
+        ),
+    },
 }
 
 # Categories with fewer fields get merged into "general" to avoid tab sprawl.
diff --git a/tests/hermes_cli/test_install_cua_driver.py b/tests/hermes_cli/test_install_cua_driver.py
index d12eacca264..f95a191512a 100644
--- a/tests/hermes_cli/test_install_cua_driver.py
+++ b/tests/hermes_cli/test_install_cua_driver.py
@@ -4,12 +4,12 @@ The cua-driver upstream installer always pulls the latest release tag, so
 re-running it is the canonical upgrade path. ``install_cua_driver(upgrade=True)``
 must:
 
-* Be macOS-only — no-op silently on Linux/Windows so ``hermes update`` can
-  call it unconditionally without warning every non-macOS user.
+* Be supported-platform-only — no-op silently elsewhere so ``hermes update``
+  can call it unconditionally without warning unsupported-platform users.
 * Re-run the installer even when the binary is already on PATH (this is the
   fix for the "we only pulled cua-driver once on enable" complaint).
 * Preserve original ``upgrade=False`` behaviour for the toolset-enable flow:
-  skip if installed, install otherwise, warn on non-macOS.
+  skip if installed, install otherwise, warn on unsupported platforms.
 
 The pre-install arch probe that used to live alongside this function was
 deleted (see top-of-file comment in tools_config.py) — the upstream
@@ -67,6 +67,41 @@ class TestInstallCuaDriverUpgrade:
             assert tools_config.install_cua_driver(upgrade=True) is True
             runner.assert_called_once()
 
+    def test_upgrade_on_macos_non_writable_applications_skips_refresh(self):
+        from hermes_cli import tools_config
+
+        with patch("platform.system", return_value="Darwin"), \
+             patch.object(tools_config.shutil, "which",
+                          side_effect=lambda n: "/usr/local/bin/" + n
+                                                 if n in {"cua-driver", "curl"} else None), \
+             patch.object(tools_config, "_cua_install_target_writable",
+                          return_value=False), \
+             patch.object(tools_config, "_run_cua_driver_installer") as runner, \
+             patch.object(tools_config, "_print_info") as info:
+            assert tools_config.install_cua_driver(upgrade=True) is True
+            runner.assert_not_called()
+            assert any(
+                "/Applications is not writable" in call.args[0]
+                for call in info.call_args_list
+            )
+
+    def test_fresh_install_on_macos_non_writable_applications_skips_install(self):
+        from hermes_cli import tools_config
+
+        with patch("platform.system", return_value="Darwin"), \
+             patch.object(tools_config.shutil, "which",
+                          side_effect=lambda n: "/usr/bin/curl" if n == "curl" else None), \
+             patch.object(tools_config, "_cua_install_target_writable",
+                          return_value=False), \
+             patch.object(tools_config, "_run_cua_driver_installer") as runner, \
+             patch.object(tools_config, "_print_info") as info:
+            assert tools_config.install_cua_driver(upgrade=False) is False
+            runner.assert_not_called()
+            assert any(
+                "/Applications is not writable" in call.args[0]
+                for call in info.call_args_list
+            )
+
     def test_non_upgrade_on_macos_with_binary_skips_install(self):
         from hermes_cli import tools_config