diff --git a/AndroidXCI/lib/src/main/kotlin/dev/androidx/ci/gcloud/GoogleCloudApi.kt b/AndroidXCI/lib/src/main/kotlin/dev/androidx/ci/gcloud/GoogleCloudApi.kt
index e0db488..7a538dc 100644
--- a/AndroidXCI/lib/src/main/kotlin/dev/androidx/ci/gcloud/GoogleCloudApi.kt
+++ b/AndroidXCI/lib/src/main/kotlin/dev/androidx/ci/gcloud/GoogleCloudApi.kt
@@ -265,6 +265,11 @@ internal interface BlobVisitor {
     val fileName: String
         get() = gcsPath.path.substringAfterLast('/')
 
+    /**
+     * The size of the blob
+     */
+    val size: Long
+
     /**
      * Opens the input stream to the blob. You must make sure to close it after using it.
      */
@@ -288,4 +293,6 @@ private class BlobVisitorImpl(
     override fun toString(): String {
         return "Blob($gcsPath)"
     }
+
+    override val size: Long = blob.size
 }
diff --git a/AndroidXCI/lib/src/main/kotlin/dev/androidx/ci/testRunner/TestRunnerService.kt b/AndroidXCI/lib/src/main/kotlin/dev/androidx/ci/testRunner/TestRunnerService.kt
index 8cddce9..292734e 100644
--- a/AndroidXCI/lib/src/main/kotlin/dev/androidx/ci/testRunner/TestRunnerService.kt
+++ b/AndroidXCI/lib/src/main/kotlin/dev/androidx/ci/testRunner/TestRunnerService.kt
@@ -238,6 +238,11 @@ interface TestRunnerService {
          * Creates an [InputStream] for the file. Note that you must close it after using.
          */
         fun openInputStream(): InputStream
+
+        /**
+         * Size of the file.
+         */
+        val size: Long
     }
 
     /**
diff --git a/AndroidXCI/lib/src/main/kotlin/dev/androidx/ci/testRunner/TestRunnerServiceImpl.kt b/AndroidXCI/lib/src/main/kotlin/dev/androidx/ci/testRunner/TestRunnerServiceImpl.kt
index 2e3bed9..0c70f8e 100644
--- a/AndroidXCI/lib/src/main/kotlin/dev/androidx/ci/testRunner/TestRunnerServiceImpl.kt
+++ b/AndroidXCI/lib/src/main/kotlin/dev/androidx/ci/testRunner/TestRunnerServiceImpl.kt
@@ -347,6 +347,7 @@ internal class TestRunnerServiceImpl internal constructor(
         private val blobVisitor: BlobVisitor
     ) : TestRunnerService.ResultFileResource {
         override val gcsPath = blobVisitor.gcsPath
+        override val size = blobVisitor.size
         override fun openInputStream(): InputStream = blobVisitor.obtainInputStream()
         override fun toString(): String {
             return "ResultFile('$gcsPath')"
diff --git a/AndroidXCI/lib/src/test/kotlin/dev/androidx/ci/fake/FakeGoogleCloudApi.kt b/AndroidXCI/lib/src/test/kotlin/dev/androidx/ci/fake/FakeGoogleCloudApi.kt
index 201630a..b5a3253 100644
--- a/AndroidXCI/lib/src/test/kotlin/dev/androidx/ci/fake/FakeGoogleCloudApi.kt
+++ b/AndroidXCI/lib/src/test/kotlin/dev/androidx/ci/fake/FakeGoogleCloudApi.kt
@@ -57,6 +57,9 @@ internal class FakeGoogleCloudApi(
                     get() = entry.key.path.substringAfter(gcsPath.path).trimStart('/')
                 override val gcsPath: GcsPath
                     get() = entry.key
+                override val size: Long
+                    get() = artifacts[gcsPath]?.size?.toLong() ?: 0
+
                 override fun obtainInputStream(): InputStream {
                     return entry.value.inputStream()
                 }
@@ -71,6 +74,9 @@ internal class FakeGoogleCloudApi(
                     get() = ""
                 override val gcsPath: GcsPath
                     get() = gcsPath
+                override val size: Long
+                    get() = artifacts[gcsPath]?.size?.toLong() ?: 0
+
                 override fun obtainInputStream(): InputStream {
                     return artifacts[gcsPath]?.inputStream() ?: InputStream.nullInputStream()
                 }