diff --git a/src/OrasProject.Oras/Packer.cs b/src/OrasProject.Oras/Packer.cs
index b526789..f4816c2 100644
--- a/src/OrasProject.Oras/Packer.cs
+++ b/src/OrasProject.Oras/Packer.cs
@@ -43,9 +43,9 @@ public static class Packer
     /// </summary>
     private const string _errMissingArtifactType = "missing artifact type";
 
-    public const string UnknownConfig = "application/vnd.unknown.config.v1+json";
+    public const string MediaTypeUnknownConfig = "application/vnd.unknown.config.v1+json";
 
-    public const string UnknownArtifact = "application/vnd.unknown.artifact.v1";
+    public const string MediaTypeUnknownArtifact = "application/vnd.unknown.artifact.v1";
 
     /// <summary>
     /// ManifestVersion represents the manifest version used for PackManifest
@@ -143,7 +143,7 @@ private static async Task<Descriptor> PackManifestV1_0Async(IPushable pusher, st
         {
             if (string.IsNullOrEmpty(artifactType))
             {
-                artifactType = UnknownConfig;
+                artifactType = MediaTypeUnknownConfig;
             }
             ValidateMediaType(artifactType);
             configDescriptor = await PushCustomEmptyConfigAsync(pusher, artifactType, options.ConfigAnnotations, cancellationToken);
diff --git a/tests/OrasProject.Oras.Tests/PackerTest.cs b/tests/OrasProject.Oras.Tests/PackerTest.cs
index 51211cc..c656d87 100644
--- a/tests/OrasProject.Oras.Tests/PackerTest.cs
+++ b/tests/OrasProject.Oras.Tests/PackerTest.cs
@@ -297,8 +297,8 @@ public async Task TestPackManifestImageV1_0_NoArtifactType()
 
         // Verify artifact type and config media type
         
-        Assert.Equal(Packer.UnknownConfig, manifestDesc.ArtifactType);
-        Assert.Equal(Packer.UnknownConfig, manifest!.Config.MediaType);
+        Assert.Equal(Packer.MediaTypeUnknownConfig, manifestDesc.ArtifactType);
+        Assert.Equal(Packer.MediaTypeUnknownConfig, manifest!.Config.MediaType);
     }
 
     [Fact]