diff --git a/tufaceous-lib/Cargo.toml b/tufaceous-lib/Cargo.toml
index 92ae34d4a1..0df3a33f98 100644
--- a/tufaceous-lib/Cargo.toml
+++ b/tufaceous-lib/Cargo.toml
@@ -30,6 +30,7 @@ serde_path_to_error.workspace = true
 sha2.workspace = true
 slog.workspace = true
 tar.workspace = true
+tokio.workspace = true
 toml.workspace = true
 tough.workspace = true
 url = "2.4.1"
diff --git a/tufaceous-lib/src/repository.rs b/tufaceous-lib/src/repository.rs
index 9b4f079b00..416d5c9990 100644
--- a/tufaceous-lib/src/repository.rs
+++ b/tufaceous-lib/src/repository.rs
@@ -89,7 +89,8 @@ impl OmicronRepo {
         let log = log.new(slog::o!("component" => "OmicronRepo"));
         let repo_path = repo_path.canonicalize_utf8()?;
         let root_json = repo_path.join("metadata").join("1.root.json");
-        let root = std::fs::read(&root_json)
+        let root = tokio::fs::read(&root_json)
+            .await
             .with_context(|| format!("error reading from {root_json}"))?;
 
         let repo = RepositoryLoader::new(
diff --git a/wicketd/src/artifacts/artifacts_with_plan.rs b/wicketd/src/artifacts/artifacts_with_plan.rs
index 01513b6f5e..d3319d7f6b 100644
--- a/wicketd/src/artifacts/artifacts_with_plan.rs
+++ b/wicketd/src/artifacts/artifacts_with_plan.rs
@@ -223,6 +223,9 @@ mod tests {
 
     /// Test that `ArtifactsWithPlan` can extract the fake repository generated
     /// by tufaceous.
+    ///
+    /// See documentation for extract_nested_artifact_pair in update_plan.rs
+    /// for why multi_thread is required.
     #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
     async fn test_extract_fake() -> Result<()> {
         let logctx = test_setup_log("test_extract_fake");
diff --git a/wicketd/src/artifacts/extracted_artifacts.rs b/wicketd/src/artifacts/extracted_artifacts.rs
index 6be9c95661..5683cd1c13 100644
--- a/wicketd/src/artifacts/extracted_artifacts.rs
+++ b/wicketd/src/artifacts/extracted_artifacts.rs
@@ -16,12 +16,11 @@ use sha2::Digest;
 use sha2::Sha256;
 use slog::info;
 use slog::Logger;
-use std::fs::File;
 use std::io;
-use std::io::BufWriter;
 use std::io::Write;
 use std::sync::Arc;
 use tokio::io::AsyncRead;
+use tokio::io::AsyncWriteExt;
 use tokio_util::io::ReaderStream;
 
 /// Handle to the data of an extracted artifact.
@@ -124,7 +123,7 @@ impl ExtractedArtifacts {
         self.tempdir.path().join(format!("{}", artifact_hash_id.hash))
     }
 
-    /// Copy from `reader` into our temp directory, returning a handle to the
+    /// Copy from `stream` into our temp directory, returning a handle to the
     /// extracted artifact on success.
     pub(super) async fn store(
         &mut self,
@@ -133,8 +132,9 @@ impl ExtractedArtifacts {
     ) -> Result<ExtractedArtifactDataHandle, RepositoryError> {
         let output_path = self.path_for_artifact(&artifact_hash_id);
 
-        let mut writer = BufWriter::new(
-            File::create(&output_path)
+        let mut writer = tokio::io::BufWriter::new(
+            tokio::fs::File::create(&output_path)
+                .await
                 .with_context(|| {
                     format!("failed to create temp file {output_path}")
                 })
@@ -156,6 +156,7 @@ impl ExtractedArtifacts {
             file_size += chunk.len();
             writer
                 .write_all(&chunk)
+                .await
                 .with_context(|| format!("failed writing to {output_path}"))
                 .map_err(|error| RepositoryError::CopyExtractedArtifact {
                     kind: artifact_hash_id.kind.clone(),
@@ -165,6 +166,7 @@ impl ExtractedArtifacts {
 
         writer
             .flush()
+            .await
             .with_context(|| format!("failed flushing {output_path}"))
             .map_err(|error| RepositoryError::CopyExtractedArtifact {
                 kind: artifact_hash_id.kind.clone(),
diff --git a/wicketd/src/artifacts/update_plan.rs b/wicketd/src/artifacts/update_plan.rs
index 9b136e4ebe..c6db7c1b65 100644
--- a/wicketd/src/artifacts/update_plan.rs
+++ b/wicketd/src/artifacts/update_plan.rs
@@ -938,6 +938,8 @@ mod tests {
         builder.build_to_vec().unwrap()
     }
 
+    // See documentation for extract_nested_artifact_pair for why multi_thread
+    // is required.
     #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
     async fn test_update_plan_from_artifacts() {
         const VERSION_0: SemverVersion = SemverVersion::new(0, 0, 0);
diff --git a/wicketd/tests/integration_tests/updates.rs b/wicketd/tests/integration_tests/updates.rs
index 4d2bdcf28e..b65833a74b 100644
--- a/wicketd/tests/integration_tests/updates.rs
+++ b/wicketd/tests/integration_tests/updates.rs
@@ -31,6 +31,8 @@ use wicketd_client::types::{
     StartUpdateParams,
 };
 
+// See documentation for extract_nested_artifact_pair in update_plan.rs for why
+// multi_thread is required.
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
 async fn test_updates() {
     let gateway = gateway_setup::test_setup("test_updates", SpPort::One).await;
@@ -258,6 +260,8 @@ async fn test_updates() {
     wicketd_testctx.teardown().await;
 }
 
+// See documentation for extract_nested_artifact_pair in update_plan.rs for why
+// multi_thread is required.
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
 async fn test_installinator_fetch() {
     let gateway = gateway_setup::test_setup("test_updates", SpPort::One).await;
@@ -391,6 +395,8 @@ async fn test_installinator_fetch() {
     wicketd_testctx.teardown().await;
 }
 
+// See documentation for extract_nested_artifact_pair in update_plan.rs for why
+// multi_thread is required.
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
 async fn test_update_races() {
     let gateway = gateway_setup::test_setup(