diff --git a/contexthub/aidl/default/ContextHub.cpp b/contexthub/aidl/default/ContextHub.cpp
index 1b56608..1fbccc5 100644
--- a/contexthub/aidl/default/ContextHub.cpp
+++ b/contexthub/aidl/default/ContextHub.cpp
@@ -21,38 +21,50 @@
 namespace hardware {
 namespace contexthub {
 
-// TODO(b/194285834): Implement AIDL HAL
+::ndk::ScopedAStatus ContextHub::getContextHubs(std::vector<ContextHubInfo>* out_contextHubInfos) {
+    ContextHubInfo hub = {};
+    hub.name = "Mock Context Hub";
+    hub.vendor = "AOSP";
+    hub.toolchain = "n/a";
+    hub.id = kMockHubId;
+    hub.peakMips = 1;
+    hub.maxSupportedMessageLengthBytes = 4096;
+    hub.chrePlatformId = UINT64_C(0x476f6f6754000000);
+    hub.chreApiMajorVersion = 1;
+    hub.chreApiMinorVersion = 6;
 
-::ndk::ScopedAStatus ContextHub::getContextHubs(
-        std::vector<ContextHubInfo>* /* out_contextHubInfos */) {
+    out_contextHubInfos->push_back(hub);
+
     return ndk::ScopedAStatus::ok();
 }
 
+// We don't expose any nanoapps for the default impl, therefore all nanoapp-related APIs fail.
 ::ndk::ScopedAStatus ContextHub::loadNanoapp(int32_t /* in_contextHubId */,
                                              const NanoappBinary& /* in_appBinary */,
-                                             int32_t /* in_transactionId */,
-                                             bool* /* _aidl_return */) {
+                                             int32_t /* in_transactionId */, bool* _aidl_return) {
+    *_aidl_return = false;
     return ndk::ScopedAStatus::ok();
 }
 
 ::ndk::ScopedAStatus ContextHub::unloadNanoapp(int32_t /* in_contextHubId */,
                                                int64_t /* in_appId */,
-                                               int32_t /* in_transactionId */,
-                                               bool* /* _aidl_return */) {
+                                               int32_t /* in_transactionId */, bool* _aidl_return) {
+    *_aidl_return = false;
     return ndk::ScopedAStatus::ok();
 }
 
 ::ndk::ScopedAStatus ContextHub::disableNanoapp(int32_t /* in_contextHubId */,
                                                 int64_t /* in_appId */,
                                                 int32_t /* in_transactionId */,
-                                                bool* /* _aidl_return */) {
+                                                bool* _aidl_return) {
+    *_aidl_return = false;
     return ndk::ScopedAStatus::ok();
 }
 
 ::ndk::ScopedAStatus ContextHub::enableNanoapp(int32_t /* in_contextHubId */,
                                                int64_t /* in_appId */,
-                                               int32_t /* in_transactionId */,
-                                               bool* /* _aidl_return */) {
+                                               int32_t /* in_transactionId */, bool* _aidl_return) {
+    *_aidl_return = false;
     return ndk::ScopedAStatus::ok();
 }
 
@@ -60,20 +72,42 @@
     return ndk::ScopedAStatus::ok();
 }
 
-::ndk::ScopedAStatus ContextHub::queryNanoapps(int32_t /* in_contextHubId */,
-                                               bool* /* _aidl_return */) {
+::ndk::ScopedAStatus ContextHub::queryNanoapps(int32_t in_contextHubId, bool* _aidl_return) {
+    if (in_contextHubId == kMockHubId && mCallback != nullptr) {
+        std::vector<NanoappInfo> nanoapps;
+        mCallback->handleNanoappInfo(nanoapps);
+        *_aidl_return = true;
+    } else {
+        *_aidl_return = false;
+    }
+
     return ndk::ScopedAStatus::ok();
 }
 
-::ndk::ScopedAStatus ContextHub::registerCallback(
-        int32_t /* in_contextHubId */, const std::shared_ptr<IContextHubCallback>& /* in_cb */,
-        bool* /* _aidl_return */) {
+::ndk::ScopedAStatus ContextHub::registerCallback(int32_t in_contextHubId,
+                                                  const std::shared_ptr<IContextHubCallback>& in_cb,
+                                                  bool* _aidl_return) {
+    if (in_contextHubId == kMockHubId) {
+        mCallback = in_cb;
+        *_aidl_return = true;
+    } else {
+        *_aidl_return = false;
+    }
     return ndk::ScopedAStatus::ok();
 }
 
-::ndk::ScopedAStatus ContextHub::sendMessageToHub(int32_t /* in_contextHubId */,
+::ndk::ScopedAStatus ContextHub::sendMessageToHub(int32_t in_contextHubId,
                                                   const ContextHubMessage& /* in_message */,
-                                                  bool* /* _aidl_return */) {
+                                                  bool* _aidl_return) {
+    if (in_contextHubId == kMockHubId) {
+        // Return true here to indicate that the HAL has accepted the message.
+        // Successful delivery of the message to a nanoapp should be handled at
+        // a higher level protocol.
+        *_aidl_return = true;
+    } else {
+        *_aidl_return = false;
+    }
+
     return ndk::ScopedAStatus::ok();
 }