diff --git a/.github/workflows/run-unit-tests.yml b/.github/workflows/run-unit-tests.yml
index 3c3393901..fa5399ccd 100644
--- a/.github/workflows/run-unit-tests.yml
+++ b/.github/workflows/run-unit-tests.yml
@@ -797,6 +797,7 @@ jobs:
           python3 -B test/test_startup_screen.py
           node test/test_notification_builder.js
           python3 -B test/test_notification_settings.py
+          python3 -B test/test_notification_led_ownership.py -v
           python3 -B test/test_display_power.py
           python3 -B test/test_legacy_ui_version_bounds.py -v
           python3 -B test/test_ssd1306_power.py -v
diff --git a/examples/companion_radio/Notifications.cpp b/examples/companion_radio/Notifications.cpp
index d3f4b329f..184221fce 100644
--- a/examples/companion_radio/Notifications.cpp
+++ b/examples/companion_radio/Notifications.cpp
@@ -3,9 +3,11 @@
 #include "NotificationSettingsFile.h"
 
 #if COMPANION_FEATURE_NOTIFICATIONS
+// The UI's STATUS_LED_RGB define is local to its own translation unit.
 uint8_t MyMesh::capabilities() const {
   uint8_t bits = _ui ? _ui->notificationCapabilities() : 0;
-#if defined(PIN_STATUS_LED) || defined(STATUS_LED_RGB)
+#if defined(PIN_STATUS_LED) || \
+    (defined(PIN_STATUS_LED_R) && defined(PIN_STATUS_LED_G) && defined(PIN_STATUS_LED_B))
   bits |= mesh::notify::Led;
 #endif
   for(unsigned pin=0;pin<64;++pin)if(gpioAvailable(pin)) { bits|=mesh::notify::Gpio;break; }
@@ -18,7 +20,7 @@ void MyMesh::pulse(mesh::notify::Output output,bool on,int8_t pin) {
   } else if(output==mesh::notify::Vibration) {
     if(_ui)_ui->notificationVibration(on);
   } else if(output==mesh::notify::Led) {
-#ifdef STATUS_LED_RGB
+#if defined(PIN_STATUS_LED_R) && defined(PIN_STATUS_LED_G) && defined(PIN_STATUS_LED_B)
     analogWrite(PIN_STATUS_LED_R,on?255:0);
     analogWrite(PIN_STATUS_LED_G,on?90:0);
     analogWrite(PIN_STATUS_LED_B,0);
diff --git a/test/fixtures/notification_led_ownership.cpp b/test/fixtures/notification_led_ownership.cpp
new file mode 100644
index 000000000..defa3fb76
--- /dev/null
+++ b/test/fixtures/notification_led_ownership.cpp
@@ -0,0 +1,241 @@
+#include "notification_harness.h"
+#include <cstdio>
+#include <cstring>
+
+namespace {
+unsigned checks = 0, failures = 0, scenarios = 0;
+const char* scenario = nullptr;
+
+void check(bool condition, const char* expression, unsigned line) {
+  ++checks;
+  if (!condition) {
+    ++failures;
+    std::printf("FAIL: %s:%u: %s [R=%u G=%u B=%u]\n", scenario, line,
+                expression, levels[3], levels[24], levels[28]);
+  }
+}
+#define CHECK(expression) check(bool(expression), #expression, __LINE__)
+
+template <typename Action>
+void run(const char* name, Action action) {
+  scenario = name;
+  ++scenarios;
+  resetIo();
+  const unsigned before = failures;
+  action();
+  if (before == failures) std::printf("PASS: %s\n", name);
+}
+
+void command(MyMesh& node, const char* text, const char* expected = "OK", uint32_t now = 1000) {
+  char reply[160] = {};
+  CHECK(node._notifications.handle(text, reply, sizeof(reply), now, false));
+  CHECK(!std::strcmp(reply, expected));
+}
+
+void expectPinFamily() {
+  for (unsigned pin = 0; pin < 64; ++pin) {
+#if EXPECT_RGB
+    CHECK(digital_writes[pin] == 0 && mode_writes[pin] == 0);
+    if (pin != 3 && pin != 24 && pin != 28) CHECK(analog_writes[pin] == 0);
+#elif EXPECT_MONO
+    CHECK(analog_writes[pin] == 0);
+    if (pin != 24) CHECK(digital_writes[pin] == 0 && mode_writes[pin] == 0);
+#else
+    CHECK(analog_writes[pin] == 0 && digital_writes[pin] == 0 && mode_writes[pin] == 0);
+#endif
+  }
+}
+
+void expectLed(bool on) {
+#if EXPECT_RGB
+  CHECK(levels[3] == (on ? 255u : 0u));
+  CHECK(levels[24] == (on ? 90u : 0u));
+  CHECK(levels[28] == 0);
+#elif EXPECT_MONO
+  CHECK(levels[24] == (on ? EXPECT_ON_LEVEL : 255 - EXPECT_ON_LEVEL));
+#else
+  (void)on;
+  CHECK(ioWrites() == 0);
+#endif
+  expectPinFamily();
+}
+
+void seedPreviousLed(MyMesh& node) {
+#if EXPECT_RGB
+  (void)node;
+  seedUiRgb();
+  CHECK(levels[3] == 200 && levels[24] == 120 && levels[28] == 90);
+#elif EXPECT_MONO
+  node.pulse(mesh::notify::Led, true, -1);
+  expectLed(true);
+#else
+  (void)node;
+  seedUiRgb();
+  CHECK(ioWrites() == 0);
+#endif
+}
+
+void checkGuard(MyMesh& node, bool admitted) {
+  const unsigned before_admitted = ui_admitted, before_writes = ioWrites();
+  node.ui.userLedHandler();
+  CHECK(ui_admitted == before_admitted + unsigned(admitted));
+  CHECK(ioWrites() == before_writes);
+}
+
+[[maybe_unused]] void startAlert(MyMesh& node) {
+  seedPreviousLed(node);
+  command(node, "set notify.led all 50,50");
+  command(node, "notify.test all", "OK - alert test started");
+  CHECK(node._notifications.active());
+  CHECK(node._notifications.ownsLed());
+}
+}  // namespace
+
+int main() {
+  run("capabilities", [] {
+    MyMesh node;
+    CHECK(bool(node.capabilities() & mesh::notify::Led) == bool(EXPECT_RGB || EXPECT_MONO));
+    CHECK(!(node.capabilities() & mesh::notify::Gpio));
+    node.ui.extra_capabilities = mesh::notify::Sound;
+    CHECK(node.capabilities() & mesh::notify::Sound);
+    node._ui = nullptr;
+    CHECK(bool(node.capabilities() & mesh::notify::Led) == bool(EXPECT_RGB || EXPECT_MONO));
+    CHECK(!(node.capabilities() & mesh::notify::Sound));
+    CHECK(ioWrites() == 0);
+  });
+
+  run("actual-ui-writer-and-ownership-guard", [] {
+    MyMesh node;
+#if EXPECT_RGB
+    seedUiRgb();
+    CHECK(levels[3] == 200 && levels[24] == 120 && levels[28] == 90);
+    clearUiRgb();
+    CHECK(levels[3] == 0 && levels[24] == 0 && levels[28] == 0);
+#else
+    seedUiRgb();
+    clearUiRgb();
+    CHECK(ioWrites() == 0);
+#endif
+    checkGuard(node, true);
+    node.ui.setNotificationLedOwnership(true);
+    checkGuard(node, false);
+    node.ui.setNotificationLedOwnership(false);
+    node.ui.setNotificationOutputs(31 & ~mesh::notify::Led);
+    checkGuard(node, false);
+    expectPinFamily();
+  });
+
+  run("master-led-off-clears-idle-ui", [] {
+    MyMesh node;
+    seedPreviousLed(node);
+    command(node, "set notify.led off");
+    CHECK(node._notifications.settings().enabled == 1);
+    CHECK(node._notifications.settings().outputs == (31 & ~mesh::notify::Led));
+    node.syncNotifications();
+    CHECK(!node.ui._notification_led_owned);
+    CHECK(!(node.ui._notification_outputs & mesh::notify::Led));
+    expectLed(false);
+    checkGuard(node, false);
+  });
+
+#if EXPECT_RGB || EXPECT_MONO
+  run("healthy-led-on-colors", [] {
+    MyMesh node;
+    command(node, "set notify.led on");
+    startAlert(node);
+    expectLed(true);
+    node.syncNotifications();
+    checkGuard(node, false);
+    node._notifications.loop(1049, false);
+    CHECK(node._notifications.active() && node._notifications.ownsLed());
+    expectLed(true);
+  });
+
+  run("inactive-pulse-phase-stays-owned", [] {
+    MyMesh node;
+    startAlert(node);
+    node._notifications.loop(1050, false);
+    CHECK(node._notifications.active() && node._notifications.ownsLed());
+    expectLed(false);
+    node.syncNotifications();
+    checkGuard(node, false);
+    node._notifications.loop(1099, false);
+    CHECK(node._notifications.active() && node._notifications.ownsLed());
+    expectLed(false);
+  });
+
+  run("command-stop-from-active-phase", [] {
+    MyMesh node;
+    startAlert(node);
+    command(node, "notify.stop", "OK - alerts stopped", 1020);
+    CHECK(!node._notifications.active() && !node._notifications.ownsLed());
+    expectLed(false);  // Check before releasing the heartbeat guard.
+    const unsigned before_writes = ioWrites();
+    command(node, "notify.stop", "OK - alerts stopped", 1021);
+    CHECK(ioWrites() == before_writes);
+    node.syncNotifications();
+    checkGuard(node, true);
+  });
+
+  run("command-stop-from-inactive-phase", [] {
+    MyMesh node;
+    startAlert(node);
+    node._notifications.loop(1050, false);
+    command(node, "notify.stop", "OK - alerts stopped", 1075);
+    CHECK(!node._notifications.active() && !node._notifications.ownsLed());
+    expectLed(false);
+    node.syncNotifications();
+    checkGuard(node, true);
+  });
+
+  run("natural-completion-clears-before-ui-release", [] {
+    MyMesh node;
+    startAlert(node);
+    node._notifications.loop(1100, false);
+    CHECK(!node._notifications.active() && !node._notifications.ownsLed());
+    expectLed(false);
+    node.syncNotifications();
+    checkGuard(node, true);
+  });
+
+  run("master-led-off-stops-active-alert", [] {
+    MyMesh node;
+    startAlert(node);
+    command(node, "set notify.led off", "OK", 1020);
+    CHECK(!node._notifications.active() && !node._notifications.ownsLed());
+    node.syncNotifications();
+    expectLed(false);
+    checkGuard(node, false);
+  });
+
+  run("disabled-feature-restores-ui-policy", [] {
+    MyMesh node;
+    startAlert(node);
+    command(node, "set notify.enabled off", "OK", 1020);
+    CHECK(!node._notifications.active() && !node._notifications.ownsLed());
+    expectLed(false);
+    node.syncNotifications();
+    CHECK(node.ui._notification_outputs == 31);
+    checkGuard(node, true);
+  });
+#else
+  run("unsupported-led-commands-and-direct-sink-are-inert", [] {
+    MyMesh node;
+    unsigned char before[sizeof(mesh::notify::Settings)];
+    std::memcpy(before, &node._notifications.settings(), sizeof(before));
+    command(node, "set notify.led on", "Error: output unsupported on this build");
+    command(node, "set notify.led all 50,50", "Error: output unsupported on this build");
+    CHECK(node.saves == 0);
+    CHECK(!std::memcmp(before, &node._notifications.settings(), sizeof(before)));
+    CHECK(!node._notifications.message(nullptr, nullptr, false, 1000));
+    node.pulse(mesh::notify::Led, true, -1);
+    node.pulse(mesh::notify::Led, false, -1);
+    expectLed(false);
+    command(node, "set notify.led all off");
+    CHECK(node.saves == 1);
+    expectLed(false);
+  });
+#endif
+  std::printf("%u scenarios, %u checks, %u failures\n", scenarios, checks, failures);
+  return failures ? 1 : 0;
+}
diff --git a/test/test_notification_led_ownership.py b/test/test_notification_led_ownership.py
new file mode 100644
index 000000000..9952c0484
--- /dev/null
+++ b/test/test_notification_led_ownership.py
@@ -0,0 +1,174 @@
+#!/usr/bin/env python3
+"""Exercise actual notification LED adapters in separate UI/sink translation units.
+
+The UI boundary is its actual RGB writer and ownership/disable guard, not the
+complete boot/flourish/heartbeat state machine. Arduino I/O, board availability,
+storage success, and unrelated UI outputs are host adapters, not hardware proof.
+"""
+
+import os
+from pathlib import Path
+import shutil
+import subprocess
+import sys
+import tempfile
+import unittest
+
+from test_replay_reset_integration import extract_braced
+
+
+ROOT = Path(__file__).resolve().parents[1]
+FIXTURE = Path(__file__).resolve().parent / "fixtures/notification_led_ownership.cpp"
+RGB = "defined(PIN_STATUS_LED_R) && defined(PIN_STATUS_LED_G) && defined(PIN_STATUS_LED_B)"
+
+HARNESS = r'''
+#pragma once
+#include <helpers/CompanionNotificationPolicy.h>
+#include <cstdint>
+#include <cstring>
+inline unsigned levels[64] = {}, analog_writes[64] = {}, digital_writes[64] = {}, mode_writes[64] = {};
+inline unsigned ui_admitted = 0;
+constexpr unsigned LOW = 0, HIGH = 1, OUTPUT = 1;
+inline void analogWrite(uint8_t pin, unsigned value) { levels[pin] = value; ++analog_writes[pin]; }
+inline void digitalWrite(uint8_t pin, unsigned value) { levels[pin] = value ? 255 : 0; ++digital_writes[pin]; }
+inline void pinMode(uint8_t pin, unsigned) { ++mode_writes[pin]; }
+inline void resetIo() {
+  std::memset(levels, 0, sizeof(levels));
+  std::memset(analog_writes, 0, sizeof(analog_writes));
+  std::memset(digital_writes, 0, sizeof(digital_writes));
+  std::memset(mode_writes, 0, sizeof(mode_writes));
+  ui_admitted = 0;
+}
+inline unsigned ioWrites() {
+  unsigned count = 0;
+  for (unsigned pin = 0; pin < 64; ++pin) count += analog_writes[pin] + digital_writes[pin] + mode_writes[pin];
+  return count;
+}
+class UITask {
+public:
+  uint8_t _notification_outputs = 31;
+  bool _notification_led_owned = false;
+  uint8_t extra_capabilities = 0;
+  @LED_OWNER@
+  @OUTPUTS@
+  uint8_t notificationCapabilities() const { return extra_capabilities; }
+  void notificationVibration(bool) {}
+  void notificationMelody(const char*) {}
+  void notificationScreen(int8_t) {}
+  void userLedHandler();
+};
+struct Board { bool isUserGpioAvailable(uint8_t) const { return false; } };
+inline Board board;
+class MyMesh : public mesh::notify::Sink, public mesh::notify::Store {
+public:
+  UITask ui;
+  UITask* _ui = &ui;
+  unsigned saves = 0;
+  mesh::notify::Controller _notifications{*this, *this};
+  uint8_t capabilities() const override;
+  bool gpioAvailable(uint8_t) const override;
+  void pulse(mesh::notify::Output, bool, int8_t) override;
+  void melody(const char*) override;
+  void screen(int8_t) override;
+  bool save(const mesh::notify::Settings&) override { ++saves; return true; }
+  void syncNotifications() { @SYNC@ }
+};
+void seedUiRgb();
+void clearUiRgb();
+'''
+
+
+def production_sources():
+    notifications = (ROOT / "examples/companion_radio/Notifications.cpp").read_text(encoding="utf-8")
+    ui = (ROOT / "examples/companion_radio/ui-orig/UITask.cpp").read_text(encoding="utf-8")
+    abstract = (ROOT / "examples/companion_radio/AbstractUITask.h").read_text(encoding="utf-8")
+    mesh = (ROOT / "examples/companion_radio/MyMesh.cpp").read_text(encoding="utf-8")
+    sync_start = mesh.index("    const auto& notifications = _notifications.settings();")
+    sync = mesh[sync_start:mesh.index("  #endif", sync_start)]
+    header = HARNESS.replace("@LED_OWNER@", extract_braced(abstract, "void setNotificationLedOwnership("))
+    header = header.replace("@OUTPUTS@", extract_braced(abstract, "void setNotificationOutputs("))
+    header = header.replace("@SYNC@", sync)
+    sink = '#include "notification_harness.h"\n' + "\n".join(
+        extract_braced(notifications, signature) for signature in (
+            "uint8_t MyMesh::capabilities(", "bool MyMesh::gpioAvailable(",
+            "void MyMesh::pulse(", "void MyMesh::melody(", "void MyMesh::screen("))
+    macro_start = ui.index("#if " + RGB)
+    macro_end = ui.index("#ifndef USER_BTN_PRESSED", macro_start)
+    actual_guard = extract_braced(ui, "void UITask::userLedHandler()")
+    guard_end = actual_guard.index("#ifdef STATUS_LED_RGB")
+    ui_source = '#include "notification_harness.h"\n' + ui[macro_start:macro_end]
+    ui_source += "\n#ifdef STATUS_LED_RGB\n" + extract_braced(ui, "static void statusLedWrite(") + "\n#endif\n"
+    ui_source += "void seedUiRgb() {\n#ifdef STATUS_LED_RGB\nstatusLedWrite(200, 120, 90);\n#endif\n}\n"
+    ui_source += "void clearUiRgb() {\n#ifdef STATUS_LED_RGB\nstatusLedWrite(0, 0, 0);\n#endif\n}\n"
+    ui_source += actual_guard[:guard_end] + "\n++ui_admitted;\n}\n"
+    return header, sink, ui_source
+
+
+class NotificationLedOwnershipTest(unittest.TestCase):
+    @classmethod
+    def setUpClass(cls):
+        cls.compiler = shutil.which("g++") or shutil.which("clang++")
+        if cls.compiler is None:
+            raise unittest.SkipTest("a host C++17 compiler is required")
+        cls.header, cls.sink, cls.ui = production_sources()
+
+    def run_variant(self, name, definitions, expected_rgb, expected_mono, on_level=255):
+        with tempfile.TemporaryDirectory(prefix="notification-led-ownership-", dir=os.environ.get("TMPDIR")) as directory:
+            work = Path(directory)
+            for filename, source in (("notification_harness.h", self.header),
+                                     ("notification_sink.cpp", self.sink), ("notification_ui.cpp", self.ui)):
+                (work / filename).write_text(source, encoding="ascii")
+            binary = work / name
+            command = [self.compiler, "-std=c++17", "-Wall", "-Wextra", "-Werror",
+                       "-Wno-misleading-indentation",
+                       *(["-fsanitize=address,undefined", "-fno-sanitize-recover=all", "-fno-pie", "-no-pie"]
+                         if sys.platform.startswith("linux") else []),
+                       *["-D" + value for value in definitions],
+                       f"-DEXPECT_RGB={int(expected_rgb)}", f"-DEXPECT_MONO={int(expected_mono)}",
+                       f"-DEXPECT_ON_LEVEL={on_level}", "-I" + str(work), "-I" + str(ROOT / "src"),
+                       str(work / "notification_sink.cpp"), str(work / "notification_ui.cpp"), str(FIXTURE),
+                       str(ROOT / "src/helpers/CompanionNotificationPolicy.cpp"), "-o", str(binary)]
+            built = subprocess.run(command, capture_output=True, text=True, timeout=60)
+            self.assertEqual(built.returncode, 0, built.stdout + built.stderr)
+            checked = subprocess.run([str(binary)], capture_output=True, text=True, timeout=20)
+            print(f"\n[{name}]\n" + checked.stdout + checked.stderr, flush=True)
+            self.assertEqual(checked.returncode, 0, checked.stdout + checked.stderr)
+            expected_scenarios = 10 if expected_rgb or expected_mono else 4
+            self.assertEqual(checked.stdout.count("PASS:"), expected_scenarios, checked.stdout)
+            self.assertRegex(checked.stdout, rf"{expected_scenarios} scenarios, [0-9]+ checks, 0 failures")
+
+    def test_meshtracker_x1_rgb(self):
+        recipe = (ROOT / "variants/meshtracker_x1/platformio.ini").read_text(encoding="utf-8")
+        for flag in ("PIN_STATUS_LED=24", "PIN_STATUS_LED_R=3", "PIN_STATUS_LED_G=24", "PIN_STATUS_LED_B=28"):
+            self.assertIn("-D " + flag, recipe)
+        self.assertIn("-I examples/companion_radio/ui-orig", recipe)
+        self.assertIn("[env:MeshTracker_X1_companion_radio_ble]", recipe)
+        self.assertNotIn("STATUS_LED_RGB", recipe)
+        self.run_variant("meshtracker-x1-rgb", ["PIN_STATUS_LED=24", "PIN_STATUS_LED_R=3",
+                         "PIN_STATUS_LED_G=24", "PIN_STATUS_LED_B=28"], True, False)
+
+    def test_complete_rgb_without_mono_alias(self):
+        self.run_variant("complete-rgb-only", ["PIN_STATUS_LED_R=3", "PIN_STATUS_LED_G=24",
+                         "PIN_STATUS_LED_B=28", "LED_STATE_ON=LOW"], True, False)
+
+    def test_mono_default_active_high(self):
+        self.run_variant("mono-default-high", ["PIN_STATUS_LED=24"], False, True)
+
+    def test_mono_explicit_active_high(self):
+        self.run_variant("mono-explicit-high", ["PIN_STATUS_LED=24", "LED_STATE_ON=HIGH"], False, True)
+
+    def test_mono_active_low(self):
+        self.run_variant("mono-low", ["PIN_STATUS_LED=24", "LED_STATE_ON=LOW"], False, True, 0)
+
+    def test_no_led(self):
+        self.run_variant("no-led", [], False, False)
+
+    def test_incomplete_rgb_is_not_led(self):
+        self.run_variant("incomplete-rgb-only", ["PIN_STATUS_LED_R=3", "PIN_STATUS_LED_G=24"], False, False)
+
+    def test_incomplete_rgb_preserves_mono(self):
+        self.run_variant("incomplete-rgb-mono", ["PIN_STATUS_LED=24", "PIN_STATUS_LED_R=3"], False, True)
+
+
+if __name__ == "__main__":
+    unittest.main(verbosity=2)