diff --git a/.codecov.yml b/.codecov.yml
new file mode 100644
index 0000000..9441a6a
--- /dev/null
+++ b/.codecov.yml
@@ -0,0 +1,8 @@
+# https://docs.codecov.com/docs/pull-request-comments
+comment:
+  layout: "diff, flags, files"
+  behavior: default
+  require_changes: false
+  require_base: false
+  require_head: true
+  hide_project_coverage: false
diff --git a/.github/workflows/pull_request_event.yml b/.github/workflows/pull_request_event.yml
index 2d52a5b..3e6f53e 100644
--- a/.github/workflows/pull_request_event.yml
+++ b/.github/workflows/pull_request_event.yml
@@ -26,4 +26,8 @@ jobs:
           distribution: 'temurin'
           java-version: 17
       - name: Test
-        run: ./gradlew clean test --info
+        run: ./gradlew clean test jacocoAggregateReport --info
+      - name: Upload the coverage report to Codecov
+        uses: codecov/codecov-action@v5
+        env:
+          CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
diff --git a/build.gradle.kts b/build.gradle.kts
index 3778660..6104fdf 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -57,9 +57,10 @@ allprojects {
         finalizedBy(tasks.jacocoTestReport)
     }
 
-    tasks.withType<JacocoReport> {
+    tasks.named<JacocoReport>("jacocoTestReport") {
         reports {
             xml.required.set(true)
+            html.required.set(true)
         }
     }
 
@@ -152,3 +153,43 @@ subprojects {
         }
     }
 }
+
+tasks.register<JacocoReport>("jacocoAggregateReport") {
+    dependsOn(subprojects.map { it.tasks.named("test") })
+
+    additionalSourceDirs.setFrom(
+        files(
+            subprojects.map {
+                it.sourceSets.main.get().allSource.srcDirs
+            },
+        ),
+    )
+    sourceDirectories.setFrom(
+        files(
+            subprojects.map {
+                it.sourceSets.main.get().allSource.srcDirs
+            },
+        ),
+    )
+    classDirectories.setFrom(
+        files(
+            subprojects.map {
+                it.sourceSets.main.get().output
+            },
+        ),
+    )
+    executionData.setFrom(
+        files(
+            subprojects.map {
+                it.buildDir.resolve("jacoco/test.exec")
+            },
+        ),
+    )
+
+    reports {
+        xml.required.set(true)
+        xml.outputLocation.set(file("$buildDir/reports/jacoco/test/jacocoTestReport.xml"))
+        html.required.set(true)
+        html.outputLocation.set(file("$buildDir/reports/jacoco/test/html"))
+    }
+}
diff --git a/core-kotlin-coroutine/src/main/kotlin/com/linecorp/cse/reqshield/kotlin/coroutine/KeyLocalLock.kt b/core-kotlin-coroutine/src/main/kotlin/com/linecorp/cse/reqshield/kotlin/coroutine/KeyLocalLock.kt
index cfc8472..5fd5375 100644
--- a/core-kotlin-coroutine/src/main/kotlin/com/linecorp/cse/reqshield/kotlin/coroutine/KeyLocalLock.kt
+++ b/core-kotlin-coroutine/src/main/kotlin/com/linecorp/cse/reqshield/kotlin/coroutine/KeyLocalLock.kt
@@ -45,7 +45,7 @@ class KeyLocalLock(private val lockTimeoutMillis: Long) : KeyLock, CoroutineScop
             while (isActive) {
                 runCatching {
                     val now = System.currentTimeMillis()
-                    lockMap.entries.removeIf { now - it.value.createdAt > lockTimeoutMillis } // 특정 시간이 지나면 lock 여부와 상관없이 map에서 삭제한다.
+                    lockMap.entries.removeIf { now - it.value.createdAt > lockTimeoutMillis }
                     delay(LOCK_MONITOR_INTERVAL_MILLIS)
                 }.onFailure { e ->
                     log.error("Error in lock lifecycle monitoring : {}", e.message)