diff --git a/Cargo.lock b/Cargo.lock
index 2e0d7a9ce..ed193980b 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2910,6 +2910,8 @@ dependencies = [
 [[package]]
 name = "oci-wasm"
 version = "0.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a91502e5352f927156f2b6a28d2558cc59558b1f441b681df3f706ced6937e07"
 dependencies = [
  "anyhow",
  "chrono",
diff --git a/crates/oci-tar-builder/Cargo.toml b/crates/oci-tar-builder/Cargo.toml
index e9b0442c6..cbedd1f4d 100644
--- a/crates/oci-tar-builder/Cargo.toml
+++ b/crates/oci-tar-builder/Cargo.toml
@@ -18,7 +18,7 @@ serde = { workspace = true }
 serde_json = { workspace = true }
 clap = { version = "4.5.7", features = ["derive"] }
 indexmap = "2.2.6"
-oci-wasm = { path = "../../../rust-oci-wasm/" }
+oci-wasm = "0.0.4"
 tokio = { version = "1.38.0", features = [ "full" ] }
 
 [lib]
diff --git a/crates/oci-tar-builder/src/lib.rs b/crates/oci-tar-builder/src/lib.rs
index 6e07f1338..16d61065c 100644
--- a/crates/oci-tar-builder/src/lib.rs
+++ b/crates/oci-tar-builder/src/lib.rs
@@ -13,16 +13,17 @@ use oci_spec::image::{
 use oci_wasm::{WasmConfig, WASM_ARCHITECTURE};
 use serde::Serialize;
 use sha256::{digest, try_digest};
-#[derive(Debug, Default)]
+#[derive(Debug)]
 pub struct Builder<C: OciConfig> {
     configs: Vec<(C, String, MediaType)>,
     layers: Vec<(PathBuf, String)>,
 }
 
-pub trait OciConfig: ToString {
+pub trait OciConfig {
     fn os(&self) -> String;
     fn architecture(&self) -> String;
     fn layers(&self) -> Vec<String>;
+    fn to_string(&self) -> String;
 }
 
 impl OciConfig for ImageConfiguration {
@@ -37,6 +38,10 @@ impl OciConfig for ImageConfiguration {
     fn layers(&self) -> Vec<String> {
         self.rootfs().diff_ids().to_vec()
     }
+
+    fn to_string(&self) -> String {
+        self.to_string_pretty().unwrap()
+    }
 }
 
 impl OciConfig for WasmConfig {
@@ -51,6 +56,28 @@ impl OciConfig for WasmConfig {
     fn layers(&self) -> Vec<String> {
         self.layer_digests.clone()
     }
+
+    fn to_string(&self) -> String {
+        serde_json::to_string_pretty(self).unwrap()
+    }
+}
+
+impl Default for Builder<WasmConfig> {
+    fn default() -> Self {
+        Self {
+            configs: Vec::new(),
+            layers: Vec::new(),
+        }
+    }
+}
+
+impl Default for Builder<ImageConfiguration> {
+    fn default() -> Self {
+        Self {
+            configs: Vec::new(),
+            layers: Vec::new(),
+        }
+    }
 }
 
 #[derive(Serialize, Debug)]
@@ -79,8 +106,6 @@ struct DockerManifest {
 
 pub const WASM_LAYER_MEDIA_TYPE: &str =
     "application/vnd.bytecodealliance.wasm.component.layer.v0+wasm";
-pub const WASM_ARTIFACT_LAYER: &str = "application/wasm";
-pub const WASM_ARTIFACT_TYPE: &str = "application/vnd.wasm.config.v0+json";
 
 impl<C: OciConfig> Builder<C> {
     pub fn add_config(&mut self, config: C, name: String, media_type: MediaType) -> &mut Self {
diff --git a/crates/wasi-demo-app/build.rs b/crates/wasi-demo-app/build.rs
index 70a336691..5b85b159a 100644
--- a/crates/wasi-demo-app/build.rs
+++ b/crates/wasi-demo-app/build.rs
@@ -59,6 +59,7 @@ fn main() {
     builder.add_config(
         img,
         "ghcr.io/containerd/runwasi/wasi-demo-app:latest".to_string(),
+        spec::MediaType::ImageConfig,
     );
 
     let f = File::create(&p).unwrap();