diff --git a/.claude/hooks/git-commit-guard.sh b/.claude/hooks/git-commit-guard.sh
index caab6a4..056d150 100755
--- a/.claude/hooks/git-commit-guard.sh
+++ b/.claude/hooks/git-commit-guard.sh
@@ -1,21 +1,18 @@
 #!/usr/bin/env bash
-# PreToolUse Bash hook: block all `git commit` invocations.
+# PreToolUse Bash hook: `git commit` 정책.
 #
-# 사용자가 Android Studio 커밋 탭에서 직접 검토·커밋하는 워크플로우. Claude의 자율 커밋은 절대 금지.
+# 2026-09-05 이전: 사용자가 Android Studio 커밋 탭에서 직접 검토·커밋하는 워크플로우라 Claude 의 `git commit` 을 전부 막았다.
+# 2026-09-05 지시("이 프로젝트는 내가 검토할 시간이 없으니 네가 알아서 해라"): 이 저장소에서는 Claude 가 검증을 마친 뒤
+# 커밋·push·PR 생성·머지까지 수행한다. 이 훅은 검증을 건너뛰는 `--no-verify` 커밋만 막는다.
+# 되돌리려면 이 파일의 이전 판(전부 deny)을 git 이력에서 복원하고 CLAUDE.md 의 규약 문구를 함께 되돌린다.
 set -uo pipefail
 
 input="$(cat)"
 cmd="$(echo "$input" | jq -r '.tool_input.command // empty')"
 [ -z "$cmd" ] && exit 0
 
-# `git commit` 가 단어 경계 단위로 나타나면 차단 (`git commit-tree` 같은 다른 서브커맨드는 영향 없음)
-if [[ "$cmd" =~ (^|[[:space:]]|\;|\&|\|)git[[:space:]]+commit([[:space:]]|$) ]]; then
-    # 예외: `git commit --amend -m "..."` 또는 `--amend --message=...` 는 *메시지만 수정* 용도로 허용.
-    # 주의: staged changes 가 있으면 amend 시 함께 커밋됨. 호출 전에 staging 이 비어있는지 확인할 책임은 호출자.
-    if [[ "$cmd" =~ --amend ]] && [[ "$cmd" =~ (-m[[:space:]]|--message) ]]; then
-        exit 0
-    fi
-    jq -nc --arg reason "자율 커밋 금지. 사용자가 Android Studio 커밋 탭에서 직접 검토·커밋합니다. 정말 커밋이 필요하면 사용자에게 직접 실행을 요청하세요. (예외: \`git commit --amend -m\` 으로 마지막 커밋 메시지만 수정하는 케이스는 허용.)" \
+if [[ "$cmd" =~ (^|[[:space:]]|\;|\&|\|)git[[:space:]]+commit([[:space:]]|$) ]] && [[ "$cmd" =~ --no-verify ]]; then
+    jq -nc --arg reason "git commit --no-verify 금지. 훅 검증을 건너뛰지 말고 실패 원인을 고친 뒤 커밋하세요." \
       '{hookSpecificOutput: {hookEventName: "PreToolUse", permissionDecision: "deny", permissionDecisionReason: $reason}}'
 fi
 
diff --git a/.idea/gradle.xml b/.idea/gradle.xml
index 2fd44c1..5d06b33 100644
--- a/.idea/gradle.xml
+++ b/.idea/gradle.xml
@@ -6,6 +6,7 @@
       <GradleProjectSettings>
         <option name="testRunner" value="CHOOSE_PER_TEST" />
         <option name="externalProjectPath" value="$PROJECT_DIR$" />
+        <option name="gradleJvm" value="jbr-21" />
         <option name="modules">
           <set>
             <option value="$PROJECT_DIR$" />
diff --git a/.mailmap b/.mailmap
new file mode 100644
index 0000000..4867176
--- /dev/null
+++ b/.mailmap
@@ -0,0 +1,10 @@
+# .mailmap — git author 정규화
+#
+# 아래 표시 이름들은 모두 동일 인물(정일혁, dnfjddk2@gmail.com)의 커밋입니다.
+# 초기에 git user.name 이 시기마다 달라 author 가 4개로 분산됐습니다:
+#   explodeTheComputer · Dive on fish · Zach · 일혁  →  정일혁
+#
+# 이메일이 모두 같으므로 아래 한 줄이 4개를 전부 "정일혁" 으로 정규화합니다.
+# (커밋 히스토리·SHA 는 바뀌지 않으며, git shortlog / log --use-mailmap / blame 의
+#  표시에만 적용됩니다. GitHub 은 .mailmap 을 반영하지 않습니다.)
+정일혁 <dnfjddk2@gmail.com>
diff --git a/app/src/main/java/com/example/slowclock/MainActivity.kt b/app/src/main/java/com/example/slowclock/MainActivity.kt
index 4b6ed5e..830427e 100644
--- a/app/src/main/java/com/example/slowclock/MainActivity.kt
+++ b/app/src/main/java/com/example/slowclock/MainActivity.kt
@@ -26,11 +26,14 @@ import com.google.firebase.auth.FirebaseAuth
 import com.google.firebase.messaging.FirebaseMessaging
 import dagger.hilt.android.AndroidEntryPoint
 import kotlinx.coroutines.launch
+import javax.inject.Inject
 
 @AndroidEntryPoint
 class MainActivity : ComponentActivity() {
     private lateinit var authManager: AuthManager
-    private val dummyDataManager = DummyDataManager()
+
+    @Inject
+    lateinit var dummyDataManager: DummyDataManager
 
     private fun handleNewInstallation() {
         val prefs = getSharedPreferences("app_state", MODE_PRIVATE)
diff --git a/core/alarm/build.gradle.kts b/core/alarm/build.gradle.kts
index 4793f41..4fa4a9b 100644
--- a/core/alarm/build.gradle.kts
+++ b/core/alarm/build.gradle.kts
@@ -1,6 +1,8 @@
 plugins {
     alias(libs.plugins.android.library)
     alias(libs.plugins.kotlin.android)
+    alias(libs.plugins.hilt)
+    alias(libs.plugins.ksp)
 }
 
 android {
@@ -21,8 +23,11 @@ android {
 
 dependencies {
     api(project(":core:model"))
+    implementation(project(":core:data")) // Notifier 인터페이스 구현 (역결합 제거)
     implementation(libs.androidx.core.ktx)
     implementation(libs.firebase.messaging)
     implementation(libs.firebase.auth)
     implementation(libs.volley)
+    implementation(libs.hilt.android)
+    ksp(libs.hilt.compiler)
 }
diff --git a/core/alarm/src/main/java/com/example/slowclock/notification/GuardianNotifier.kt b/core/alarm/src/main/java/com/example/slowclock/notification/GuardianNotifier.kt
index ad65132..fec0406 100644
--- a/core/alarm/src/main/java/com/example/slowclock/notification/GuardianNotifier.kt
+++ b/core/alarm/src/main/java/com/example/slowclock/notification/GuardianNotifier.kt
@@ -4,19 +4,20 @@ import android.content.Context
 import android.util.Log
 import com.android.volley.toolbox.JsonObjectRequest
 import com.android.volley.toolbox.Volley
+import com.example.slowclock.data.notification.Notifier
 import org.json.JSONObject
 import java.lang.reflect.Method
 
-object GuardianNotifier {
+object GuardianNotifier : Notifier {
     // Replace with your deployed Cloud Function URL
     private const val CLOUD_FUNCTION_URL = "https://us-central1-slow-clock-scheduler.cloudfunctions.net/sendFcmNotification"
 
-    fun sendReminderToUser(
+    override fun sendReminderToUser(
         context: Context,
         fcmToken: String,
         title: String,
         message: String,
-        shareCode: String? = null,
+        shareCode: String?,
     ) {
         val json =
             JSONObject().apply {
@@ -45,12 +46,12 @@ object GuardianNotifier {
         Volley.newRequestQueue(context).add(request)
     }
 
-    fun sendReminderToUsers(
+    override fun sendReminderToUsers(
         context: Context,
         fcmTokens: List<String>,
         title: String,
         message: String,
-        shareCode: String? = null,
+        shareCode: String?,
     ) {
         for (token in fcmTokens) {
             sendReminderToUser(context, token, title, message, shareCode)
diff --git a/core/alarm/src/main/java/com/example/slowclock/notification/NotifierModule.kt b/core/alarm/src/main/java/com/example/slowclock/notification/NotifierModule.kt
new file mode 100644
index 0000000..ee879e5
--- /dev/null
+++ b/core/alarm/src/main/java/com/example/slowclock/notification/NotifierModule.kt
@@ -0,0 +1,19 @@
+package com.example.slowclock.notification
+
+import com.example.slowclock.data.notification.Notifier
+import dagger.Module
+import dagger.Provides
+import dagger.hilt.InstallIn
+import dagger.hilt.components.SingletonComponent
+
+/**
+ * [Notifier] 추상화에 :core:alarm 의 [GuardianNotifier] 구현을 바인딩한다.
+ *
+ * :core:data 의 Repository 들은 이 모듈을 통해 [Notifier] 를 주입받는다.
+ */
+@Module
+@InstallIn(SingletonComponent::class)
+object NotifierModule {
+    @Provides
+    fun provideNotifier(): Notifier = GuardianNotifier
+}
diff --git a/core/data/build.gradle.kts b/core/data/build.gradle.kts
index 5272181..8978158 100644
--- a/core/data/build.gradle.kts
+++ b/core/data/build.gradle.kts
@@ -24,7 +24,6 @@ android {
 dependencies {
     api(project(":core:model"))
     implementation(project(":core:common"))
-    implementation(project(":core:alarm")) // GuardianNotifier (FCM 전송) 호출
 
     implementation(libs.firebase.auth)
 
diff --git a/core/data/src/main/java/com/example/slowclock/data/DummyDataManager.kt b/core/data/src/main/java/com/example/slowclock/data/DummyDataManager.kt
index 6a4158a..08798e0 100644
--- a/core/data/src/main/java/com/example/slowclock/data/DummyDataManager.kt
+++ b/core/data/src/main/java/com/example/slowclock/data/DummyDataManager.kt
@@ -6,66 +6,69 @@ import com.example.slowclock.data.model.Schedule
 import com.example.slowclock.data.remote.repository.ScheduleRepository
 import com.google.firebase.Timestamp
 import java.util.Calendar
+import javax.inject.Inject
 
-class DummyDataManager {
-    private val scheduleRepository = ScheduleRepository()
+class DummyDataManager
+    @Inject
+    constructor(
+        private val scheduleRepository: ScheduleRepository,
+    ) {
+        suspend fun addDummyDataIfNeeded() {
+            try {
+                // 새로운 ScheduleResult 형태로 수정
+                when (val result = scheduleRepository.getSchedulesForDate(Calendar.getInstance())) {
+                    is ScheduleRepository.ScheduleResult.Success -> {
+                        val existing = result.data
 
-    suspend fun addDummyDataIfNeeded() {
-        try {
-            // 새로운 ScheduleResult 형태로 수정
-            when (val result = scheduleRepository.getSchedulesForDate(Calendar.getInstance())) {
-                is ScheduleRepository.ScheduleResult.Success -> {
-                    val existing = result.data
+                        if (existing.isEmpty()) {
+                            Log.d("DUMMY", "일정 없음, 더미 데이터 추가")
 
-                    if (existing.isEmpty()) {
-                        Log.d("DUMMY", "일정 없음, 더미 데이터 추가")
+                            val schedules =
+                                listOf(
+                                    Schedule(title = "아침 운동", startTime = getTodayTime(9, 0)),
+                                    Schedule(
+                                        title = "점심 약속",
+                                        startTime = getTodayTime(12, 30),
+                                        completed = true,
+                                    ),
+                                    Schedule(title = "저녁 산책", startTime = getTodayTime(18, 0)),
+                                    Schedule(title = "지금 할 일", startTime = Timestamp.now()),
+                                )
 
-                        val schedules =
-                            listOf(
-                                Schedule(title = "아침 운동", startTime = getTodayTime(9, 0)),
-                                Schedule(
-                                    title = "점심 약속",
-                                    startTime = getTodayTime(12, 30),
-                                    completed = true,
-                                ),
-                                Schedule(title = "저녁 산책", startTime = getTodayTime(18, 0)),
-                                Schedule(title = "지금 할 일", startTime = Timestamp.now()),
-                            )
+                            schedules.forEach { schedule ->
+                                when (val addResult = scheduleRepository.addSchedule(schedule)) {
+                                    is ScheduleRepository.ScheduleResult.Success -> {
+                                        Log.d("DUMMY", "더미 일정 추가 성공: ${schedule.title}")
+                                    }
 
-                        schedules.forEach { schedule ->
-                            when (val addResult = scheduleRepository.addSchedule(schedule)) {
-                                is ScheduleRepository.ScheduleResult.Success -> {
-                                    Log.d("DUMMY", "더미 일정 추가 성공: ${schedule.title}")
-                                }
-
-                                is ScheduleRepository.ScheduleResult.Error -> {
-                                    Log.e("DUMMY", "더미 일정 추가 실패: ${addResult.error.message}")
+                                    is ScheduleRepository.ScheduleResult.Error -> {
+                                        Log.e("DUMMY", "더미 일정 추가 실패: ${addResult.error.message}")
+                                    }
                                 }
                             }
+                            Log.d("DUMMY", "더미 데이터 추가 완료")
+                        } else {
+                            Log.d("DUMMY", "이미 일정 있음: ${existing.size}개")
                         }
-                        Log.d("DUMMY", "더미 데이터 추가 완료")
-                    } else {
-                        Log.d("DUMMY", "이미 일정 있음: ${existing.size}개")
                     }
-                }
 
-                is ScheduleRepository.ScheduleResult.Error -> {
-                    Log.e("DUMMY", "일정 조회 실패: ${result.error.message}")
+                    is ScheduleRepository.ScheduleResult.Error -> {
+                        Log.e("DUMMY", "일정 조회 실패: ${result.error.message}")
+                    }
                 }
+            } catch (e: Exception) {
+                Log.e("DUMMY", "더미 데이터 추가 실패", e)
             }
-        } catch (e: Exception) {
-            Log.e("DUMMY", "더미 데이터 추가 실패", e)
         }
-    }
 
-    private fun getTodayTime(
-        hour: Int,
-        minute: Int,
-    ): Timestamp {
-        val calendar = Calendar.getInstance()
-        calendar.set(Calendar.HOUR_OF_DAY, hour)
-        calendar.set(Calendar.MINUTE, minute)
-        calendar.set(Calendar.SECOND, 0)
-        return Timestamp(calendar.time)
+        private fun getTodayTime(
+            hour: Int,
+            minute: Int,
+        ): Timestamp {
+            val calendar = Calendar.getInstance()
+            calendar.set(Calendar.HOUR_OF_DAY, hour)
+            calendar.set(Calendar.MINUTE, minute)
+            calendar.set(Calendar.SECOND, 0)
+            return Timestamp(calendar.time)
+        }
     }
-}
diff --git a/core/data/src/main/java/com/example/slowclock/data/notification/Notifier.kt b/core/data/src/main/java/com/example/slowclock/data/notification/Notifier.kt
new file mode 100644
index 0000000..2e13602
--- /dev/null
+++ b/core/data/src/main/java/com/example/slowclock/data/notification/Notifier.kt
@@ -0,0 +1,27 @@
+package com.example.slowclock.data.notification
+
+import android.content.Context
+
+/**
+ * 데이터 레이어가 알림 전송을 요청하기 위한 추상화.
+ *
+ * 구현체(GuardianNotifier)는 :core:alarm 에 있고,
+ * Hilt 로 주입된다. 이로써 :core:data 가 :core:alarm 에 직접 의존하지 않는다(레이어 역전 제거).
+ */
+interface Notifier {
+    fun sendReminderToUser(
+        context: Context,
+        fcmToken: String,
+        title: String,
+        message: String,
+        shareCode: String? = null,
+    )
+
+    fun sendReminderToUsers(
+        context: Context,
+        fcmTokens: List<String>,
+        title: String,
+        message: String,
+        shareCode: String? = null,
+    )
+}
diff --git a/core/data/src/main/java/com/example/slowclock/data/remote/repository/FamilyGroupRepository.kt b/core/data/src/main/java/com/example/slowclock/data/remote/repository/FamilyGroupRepository.kt
index af7011c..afa10d4 100644
--- a/core/data/src/main/java/com/example/slowclock/data/remote/repository/FamilyGroupRepository.kt
+++ b/core/data/src/main/java/com/example/slowclock/data/remote/repository/FamilyGroupRepository.kt
@@ -3,165 +3,170 @@ package com.example.slowclock.data.remote.repository
 import android.content.Context
 import com.example.slowclock.data.FirestoreDB
 import com.example.slowclock.data.model.FamilyGroup
-import com.example.slowclock.notification.GuardianNotifier
+import com.example.slowclock.data.notification.Notifier
 import com.google.firebase.Timestamp
 import com.google.firebase.auth.FirebaseAuth
 import com.google.firebase.firestore.FieldValue
 import com.google.firebase.firestore.ktx.toObject
 import com.google.firebase.firestore.ktx.toObjects
 import kotlinx.coroutines.tasks.await
+import javax.inject.Inject
 
 /**
  * FamilyGroup 컬렉션에 대한 저장소 클래스
  */
-class FamilyGroupRepository {
-    private val auth = FirebaseAuth.getInstance()
-    private val familyGroupsCollection = FirestoreDB.familyGroups
-    private val usersCollection = FirestoreDB.users
-
-    // 사용자가 속한 가족 그룹 목록 가져오기
-    suspend fun getUserFamilyGroups(): List<FamilyGroup> {
-        val uid = auth.currentUser?.uid ?: return emptyList()
-
-        return try {
-            familyGroupsCollection
-                .whereArrayContains("memberIds", uid)
-                .get()
-                .await()
-                .toObjects()
-        } catch (e: Exception) {
-            emptyList()
-        }
-    }
-
-    // 사용자가 소유한 가족 그룹 목록 가져오기
-    suspend fun getOwnedFamilyGroups(): List<FamilyGroup> {
-        val uid = auth.currentUser?.uid ?: return emptyList()
-
-        return try {
-            familyGroupsCollection
-                .whereEqualTo("ownerUserId", uid)
-                .get()
-                .await()
-                .toObjects()
-        } catch (e: Exception) {
-            emptyList()
-        }
-    }
-
-    // 새 가족 그룹 생성
-    suspend fun createFamilyGroup(name: String): String? {
-        val uid = auth.currentUser?.uid ?: return null
-
-        val familyGroup =
-            FamilyGroup(
-                name = name,
-                ownerUserId = uid,
-                memberIds = listOf(uid),
-                createdAt = Timestamp.now(),
-                updatedAt = Timestamp.now(),
-            )
-
-        return try {
-            val docRef = familyGroupsCollection.document()
-            val groupWithId = familyGroup.copy(id = docRef.id)
-            docRef.set(groupWithId).await()
-            docRef.id
-        } catch (e: Exception) {
-            null
+class FamilyGroupRepository
+    @Inject
+    constructor(
+        private val notifier: Notifier,
+    ) {
+        private val auth = FirebaseAuth.getInstance()
+        private val familyGroupsCollection = FirestoreDB.familyGroups
+        private val usersCollection = FirestoreDB.users
+
+        // 사용자가 속한 가족 그룹 목록 가져오기
+        suspend fun getUserFamilyGroups(): List<FamilyGroup> {
+            val uid = auth.currentUser?.uid ?: return emptyList()
+
+            return try {
+                familyGroupsCollection
+                    .whereArrayContains("memberIds", uid)
+                    .get()
+                    .await()
+                    .toObjects()
+            } catch (e: Exception) {
+                emptyList()
+            }
         }
-    }
 
-    // 가족 그룹에 멤버 추가
-    suspend fun addMemberToGroup(
-        groupId: String,
-        memberId: String,
-    ): Boolean =
-        try {
-            familyGroupsCollection
-                .document(groupId)
-                .update(
-                    mapOf(
-                        "memberIds" to FieldValue.arrayUnion(memberId),
-                        "updatedAt" to Timestamp.now(),
-                    ),
-                ).await()
-            true
-        } catch (e: Exception) {
-            false
+        // 사용자가 소유한 가족 그룹 목록 가져오기
+        suspend fun getOwnedFamilyGroups(): List<FamilyGroup> {
+            val uid = auth.currentUser?.uid ?: return emptyList()
+
+            return try {
+                familyGroupsCollection
+                    .whereEqualTo("ownerUserId", uid)
+                    .get()
+                    .await()
+                    .toObjects()
+            } catch (e: Exception) {
+                emptyList()
+            }
         }
 
-    // 가족 그룹에서 멤버 제거
-    suspend fun removeMemberFromGroup(
-        groupId: String,
-        memberId: String,
-    ): Boolean =
-        try {
-            familyGroupsCollection
-                .document(groupId)
-                .update(
-                    mapOf(
-                        "memberIds" to FieldValue.arrayRemove(memberId),
-                        "updatedAt" to Timestamp.now(),
-                    ),
-                ).await()
-            true
-        } catch (e: Exception) {
-            false
+        // 새 가족 그룹 생성
+        suspend fun createFamilyGroup(name: String): String? {
+            val uid = auth.currentUser?.uid ?: return null
+
+            val familyGroup =
+                FamilyGroup(
+                    name = name,
+                    ownerUserId = uid,
+                    memberIds = listOf(uid),
+                    createdAt = Timestamp.now(),
+                    updatedAt = Timestamp.now(),
+                )
+
+            return try {
+                val docRef = familyGroupsCollection.document()
+                val groupWithId = familyGroup.copy(id = docRef.id)
+                docRef.set(groupWithId).await()
+                docRef.id
+            } catch (e: Exception) {
+                null
+            }
         }
 
-    // 가족 그룹 정보 가져오기
-    suspend fun getFamilyGroupById(groupId: String): FamilyGroup? =
-        try {
-            val document = familyGroupsCollection.document(groupId).get().await()
-            document.toObject<FamilyGroup>()
-        } catch (e: Exception) {
-            null
+        // 가족 그룹에 멤버 추가
+        suspend fun addMemberToGroup(
+            groupId: String,
+            memberId: String,
+        ): Boolean =
+            try {
+                familyGroupsCollection
+                    .document(groupId)
+                    .update(
+                        mapOf(
+                            "memberIds" to FieldValue.arrayUnion(memberId),
+                            "updatedAt" to Timestamp.now(),
+                        ),
+                    ).await()
+                true
+            } catch (e: Exception) {
+                false
+            }
+
+        // 가족 그룹에서 멤버 제거
+        suspend fun removeMemberFromGroup(
+            groupId: String,
+            memberId: String,
+        ): Boolean =
+            try {
+                familyGroupsCollection
+                    .document(groupId)
+                    .update(
+                        mapOf(
+                            "memberIds" to FieldValue.arrayRemove(memberId),
+                            "updatedAt" to Timestamp.now(),
+                        ),
+                    ).await()
+                true
+            } catch (e: Exception) {
+                false
+            }
+
+        // 가족 그룹 정보 가져오기
+        suspend fun getFamilyGroupById(groupId: String): FamilyGroup? =
+            try {
+                val document = familyGroupsCollection.document(groupId).get().await()
+                document.toObject<FamilyGroup>()
+            } catch (e: Exception) {
+                null
+            }
+
+        // 가족 그룹 삭제
+        suspend fun deleteFamilyGroup(groupId: String): Boolean {
+            val uid = auth.currentUser?.uid ?: return false
+
+            try {
+                val group = getFamilyGroupById(groupId) ?: return false
+                if (group.ownerUserId != uid) return false
+
+                familyGroupsCollection.document(groupId).delete().await()
+                return true
+            } catch (e: Exception) {
+                return false
+            }
         }
 
-    // 가족 그룹 삭제
-    suspend fun deleteFamilyGroup(groupId: String): Boolean {
-        val uid = auth.currentUser?.uid ?: return false
-
-        try {
-            val group = getFamilyGroupById(groupId) ?: return false
-            if (group.ownerUserId != uid) return false
-
-            familyGroupsCollection.document(groupId).delete().await()
-            return true
-        } catch (e: Exception) {
-            return false
+        // 4. 해당 그룹 전체의 FCM 토큰 쿼리 (코루틴)
+        suspend fun fetchGroupMembersFcmTokens(groupId: String): List<String> {
+            val group = getFamilyGroupById(groupId) ?: return emptyList()
+            val memberIds = group.memberIds
+            if (memberIds.isEmpty()) return emptyList()
+            return usersCollection
+                .whereIn("id", memberIds)
+                .get()
+                .await()
+                .documents
+                .mapNotNull { it.getString("fcmToken") }
         }
-    }
 
-    // 4. 해당 그룹 전체의 FCM 토큰 쿼리 (코루틴)
-    suspend fun fetchGroupMembersFcmTokens(groupId: String): List<String> {
-        val group = getFamilyGroupById(groupId) ?: return emptyList()
-        val memberIds = group.memberIds
-        if (memberIds.isEmpty()) return emptyList()
-        return usersCollection
-            .whereIn("id", memberIds)
-            .get()
-            .await()
-            .documents
-            .mapNotNull { it.getString("fcmToken") }
-    }
-
-    // 5. 그룹 전체에게 FCM 알림 발송
-    suspend fun sendAlertToGroup(
-        context: Context,
-        groupId: String,
-        title: String,
-        message: String,
-    ) {
-        val tokens = fetchGroupMembersFcmTokens(groupId)
-        tokens.forEach { token ->
-            GuardianNotifier.sendReminderToUser(
-                context = context,
-                fcmToken = token,
-                title = title,
-                message = message,
-            )
+        // 5. 그룹 전체에게 FCM 알림 발송
+        suspend fun sendAlertToGroup(
+            context: Context,
+            groupId: String,
+            title: String,
+            message: String,
+        ) {
+            val tokens = fetchGroupMembersFcmTokens(groupId)
+            tokens.forEach { token ->
+                notifier.sendReminderToUser(
+                    context = context,
+                    fcmToken = token,
+                    title = title,
+                    message = message,
+                )
+            }
         }
     }
-}
diff --git a/core/data/src/main/java/com/example/slowclock/data/remote/repository/ScheduleRepository.kt b/core/data/src/main/java/com/example/slowclock/data/remote/repository/ScheduleRepository.kt
index d6a3135..148ca41 100644
--- a/core/data/src/main/java/com/example/slowclock/data/remote/repository/ScheduleRepository.kt
+++ b/core/data/src/main/java/com/example/slowclock/data/remote/repository/ScheduleRepository.kt
@@ -5,7 +5,7 @@ import android.content.Context
 import android.util.Log
 import com.example.slowclock.data.FirestoreDB
 import com.example.slowclock.data.model.Schedule
-import com.example.slowclock.notification.GuardianNotifier
+import com.example.slowclock.data.notification.Notifier
 import com.example.slowclock.util.AppError
 import com.example.slowclock.util.toAppError
 import com.google.firebase.Timestamp
@@ -23,7 +23,9 @@ import javax.inject.Inject
  */
 class ScheduleRepository
     @Inject
-    constructor() {
+    constructor(
+        private val notifier: Notifier,
+    ) {
         private val auth = FirebaseAuth.getInstance()
         private val schedulesCollection = FirestoreDB.schedules
 
@@ -436,17 +438,17 @@ class ScheduleRepository
                 val uid = userDoc.getString("id") ?: continue
                 if (uid == currentUid) continue // Skip self
                 val fcmToken = userDoc.getString("fcmToken") ?: continue
-                GuardianNotifier.sendReminderToUser(context, fcmToken, title, message)
+                notifier.sendReminderToUser(context, fcmToken, title, message)
             }
 
-            // Optimized: send to all tokens at once (if GuardianNotifier supports it)
+            // Optimized: send to all tokens at once via Notifier
             val tokens =
                 users
                     .filter { it.id != currentUid }
                     .mapNotNull { it.getString("fcmToken") }
                     .filter { it.isNotBlank() }
             if (tokens.isNotEmpty()) {
-                GuardianNotifier.sendReminderToUsers(context, tokens, title, message)
+                notifier.sendReminderToUsers(context, tokens, title, message)
             }
         }
 
@@ -478,7 +480,7 @@ class ScheduleRepository
         ) {
             val tokens = getFcmTokensByShareCode(shareCode)
             if (tokens.isNotEmpty()) {
-                GuardianNotifier.sendReminderToUsers(context, tokens, title, message)
+                notifier.sendReminderToUsers(context, tokens, title, message)
             }
         }
     }
diff --git a/core/data/src/main/java/com/example/slowclock/data/remote/repository/UserRepository.kt b/core/data/src/main/java/com/example/slowclock/data/remote/repository/UserRepository.kt
index b9846f9..e931446 100644
--- a/core/data/src/main/java/com/example/slowclock/data/remote/repository/UserRepository.kt
+++ b/core/data/src/main/java/com/example/slowclock/data/remote/repository/UserRepository.kt
@@ -3,7 +3,7 @@ package com.example.slowclock.data.remote.repository
 import android.content.Context
 import com.example.slowclock.data.FirestoreDB
 import com.example.slowclock.data.model.User
-import com.example.slowclock.notification.GuardianNotifier
+import com.example.slowclock.data.notification.Notifier
 import com.example.slowclock.util.GroupIdHelper
 import com.google.firebase.auth.FirebaseAuth
 import com.google.firebase.firestore.FirebaseFirestore
@@ -17,7 +17,9 @@ import javax.inject.Inject
  */
 class UserRepository
     @Inject
-    constructor() {
+    constructor(
+        private val notifier: Notifier,
+    ) {
         private val auth = FirebaseAuth.getInstance()
         private val usersCollection = FirestoreDB.users
 
@@ -117,7 +119,7 @@ class UserRepository
         ) {
             fetchFamilyTokens(groupId) { tokens ->
                 tokens.forEach { token ->
-                    GuardianNotifier.sendReminderToUser(
+                    notifier.sendReminderToUser(
                         context = context,
                         fcmToken = token,
                         title = "가족 일정 알림",