diff --git a/CMakeLists.txt b/CMakeLists.txt
index b7bf202..b977ac9 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -6,7 +6,7 @@ if(NOT CMAKE_GENERATOR MATCHES "^(Ninja|Xcode)$")
 endif()
 
 cmake_minimum_required(VERSION 3.21)
-project(xone_macos VERSION 0.1.25 LANGUAGES CXX Swift)
+project(xone_macos VERSION 0.1.26 LANGUAGES CXX Swift)
 
 set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
 
diff --git a/include/app/xone_api.h b/include/app/xone_api.h
index ace592d..48b6cda 100644
--- a/include/app/xone_api.h
+++ b/include/app/xone_api.h
@@ -74,7 +74,8 @@ int xone_controller_mac(xone_dongle const *d, int index, char *buf, int len);
 
 // Snapshot of the latest standard Xbox controller input report. Stick values
 // are signed 16-bit values; trigger values are unsigned 10-bit values. The
-// buttons field uses the standard GIP gamepad bit assignments.
+// buttons field uses the standard GIP gamepad bit assignments. Battery fields
+// come from periodic GIP status packets (battery_type is 0 when unknown).
 struct xone_controller_state {
     uint16_t buttons;
     bool guide_down;
@@ -87,6 +88,8 @@ struct xone_controller_state {
     int16_t stick_right_x;
     int16_t stick_right_y;
     uint32_t sequence;
+    uint8_t battery_type;
+    uint8_t battery_level;
 };
 
 // Copy the latest input state for the controller at index. Returns 0 on
@@ -97,6 +100,12 @@ int xone_controller_get_state(xone_dongle const *d, int index,
 // Enter or leave pairing mode (beacon pairing flag + LED blink).
 void xone_set_pairing(xone_dongle *d, bool enable);
 
+// Trigger a rumble test on the controller at index. Returns 0 on success,
+// -1 for an invalid session or index. Not implemented yet: host to
+// controller TX (GIP_CMD_RUMBLE payload) is pending, so this currently
+// returns -ENOSYS.
+int xone_controller_rumble(xone_dongle *d, int index);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/app/ContentView.swift b/src/app/ContentView.swift
index b605681..ddcd11d 100644
--- a/src/app/ContentView.swift
+++ b/src/app/ContentView.swift
@@ -43,7 +43,9 @@ struct ContentView: View {
             } else {
                 LazyVGrid(columns: cardColumns, alignment: .leading, spacing: 16) {
                     ForEach(store.controllers) { controller in
-                        ControllerCardView(controller: controller)
+                        ControllerCardView(controller: controller) {
+                            store.testRumble(controller)
+                        }
                     }
                 }
             }
diff --git a/src/app/ControllerCardView.swift b/src/app/ControllerCardView.swift
index 0ce2540..b89097c 100644
--- a/src/app/ControllerCardView.swift
+++ b/src/app/ControllerCardView.swift
@@ -8,6 +8,7 @@ import SwiftUI
 
 struct ControllerCardView: View {
     let controller: ControllerInput
+    var onRumble: () -> Void = {}
 
     var body: some View {
         VStack(alignment: .leading, spacing: 12) {
@@ -33,6 +34,13 @@ struct ControllerCardView: View {
             Text(controller.id)
                 .font(.system(.callout, design: .monospaced))
             Spacer()
+            if let symbol = controller.batterySymbol {
+                Image(systemName: symbol)
+                    .font(.caption)
+            }
+            Button("Rumble") { onRumble() }
+                .controlSize(.small)
+                .disabled(!controller.gipReady)
             Text(controller.gipReady ? "ready" : "connecting")
                 .font(.caption.weight(.medium))
                 .foregroundStyle(controller.gipReady ? .green : .orange)
diff --git a/src/app/XoneModels.swift b/src/app/XoneModels.swift
index deb015f..e25c92c 100644
--- a/src/app/XoneModels.swift
+++ b/src/app/XoneModels.swift
@@ -32,10 +32,23 @@ struct ControllerInput: Identifiable {
     let stickRightX: Int16
     let stickRightY: Int16
     let sequence: UInt32
+    let batteryType: UInt8
+    let batteryLevel: UInt8
 
     func isPressed(_ button: XboxButton) -> Bool {
         (buttons & button.mask) != 0
     }
+
+    // SF Symbol for the battery level; nil when there is no battery info.
+    var batterySymbol: String? {
+        guard batteryType != 0 else { return nil }
+        switch batteryLevel {
+        case 0: return "battery.25"
+        case 1: return "battery.50"
+        case 2: return "battery.75"
+        default: return "battery.100"
+        }
+    }
 }
 
 // Standard GIP gamepad buttons and their bit masks. Guide is a separate flag
diff --git a/src/app/XoneStore.swift b/src/app/XoneStore.swift
index 8b4f149..648696e 100644
--- a/src/app/XoneStore.swift
+++ b/src/app/XoneStore.swift
@@ -33,6 +33,17 @@ final class XoneStore: ObservableObject {
         xone_set_pairing(s, pairingActive)
     }
 
+    // Rumble test seam: the C API returns -ENOSYS until host to controller
+    // TX is implemented.
+    func testRumble(_ controller: ControllerInput) {
+        guard let s = session,
+              let index = controllers.firstIndex(where: { $0.id == controller.id })
+        else { return }
+        if xone_controller_rumble(s, Int32(index)) != 0 {
+            NSLog("xone: rumble TX not implemented yet")
+        }
+    }
+
     private func poll() {
         let present = xone_dongle_present()
         donglePresent = present
@@ -97,7 +108,9 @@ final class XoneStore: ObservableObject {
                 stickLeftY: raw.stick_left_y,
                 stickRightX: raw.stick_right_x,
                 stickRightY: raw.stick_right_y,
-                sequence: raw.sequence
+                sequence: raw.sequence,
+                batteryType: raw.battery_type,
+                batteryLevel: raw.battery_level
             ))
         }
         return list
diff --git a/src/app/api.cpp b/src/app/api.cpp
index 14e2eca..698e37e 100644
--- a/src/app/api.cpp
+++ b/src/app/api.cpp
@@ -4,6 +4,7 @@
 
 #include <array>
 #include <atomic>
+#include <cerrno>
 #include <cstdio>
 #include <cstring>
 #include <memory>
@@ -59,6 +60,8 @@ public:
     auto on_client_added(xone::gip::client&) -> void override;
     auto on_client_removed(std::uint8_t) -> void override;
     auto on_guide_button(xone::gip::client&, bool down) -> void override;
+    auto on_battery(xone::gip::client&, std::uint8_t type, std::uint8_t level)
+        -> void override;
     auto on_input(xone::gip::client&, std::span<std::uint8_t const> data)
         -> void override;
 
@@ -83,6 +86,9 @@ struct controller {
     bool input_active = false;
     bool guide_down = false;
     bool gip_ready = false;
+    // From periodic GIP status packets (GIP_BATT_TYPE_*/LEVEL_*).
+    std::uint8_t battery_type = 0;
+    std::uint8_t battery_level = 0;
 
     // Declared in dependency order so adapter is destroyed before its bridge.
     std::unique_ptr<controller_transport> gip_transport;
@@ -201,6 +207,14 @@ auto controller_listener::on_guide_button(xone::gip::client&, bool down)
     m_controller.guide_down = down;
 }
 
+auto controller_listener::on_battery(xone::gip::client&, std::uint8_t type,
+                                     std::uint8_t level) -> void
+{
+    std::lock_guard<std::mutex> guard(m_dongle.lock);
+    m_controller.battery_type = type;
+    m_controller.battery_level = level;
+}
+
 auto controller_listener::on_input(
     xone::gip::client&, std::span<std::uint8_t const> data) -> void
 {
@@ -695,6 +709,8 @@ extern "C" int xone_controller_get_state(
     state->stick_right_x = c.stick_right_x;
     state->stick_right_y = c.stick_right_y;
     state->sequence = c.input_sequence;
+    state->battery_type = c.battery_type;
+    state->battery_level = c.battery_level;
     return 0;
 }
 
@@ -704,3 +720,18 @@ extern "C" void xone_set_pairing(xone_dongle *d, bool enable)
 {
     d->set_pairing(enable);
 }
+
+// Rumble test seam: host to controller TX is not implemented yet (the
+// GIP_CMD_RUMBLE payload format is undefined), so this only validates its
+// arguments for now.
+extern "C" int xone_controller_rumble(xone_dongle *d, int index)
+{
+    if (!d)
+        return -1;
+
+    std::lock_guard<std::mutex> guard(d->lock);
+    if (index < 0 || index >= static_cast<int>(d->controllers.size()))
+        return -1;
+
+    return -ENOSYS;
+}