diff --git a/rust_backend/crates/extensions/src/backend/provider_metadata.rs b/rust_backend/crates/extensions/src/backend/provider_metadata.rs
index 98df916f..57c2bb2f 100644
--- a/rust_backend/crates/extensions/src/backend/provider_metadata.rs
+++ b/rust_backend/crates/extensions/src/backend/provider_metadata.rs
@@ -392,10 +392,17 @@ fn response(kind: &str, value: &Value, check: &Check<'_>) -> Result<Value, Resol
     check().map_err(ResolverError::Cancelled)?;
     let cover = text(value, "cover_url");
     Ok(match kind {
-        "track" => json!({"track":track(value, "", 0)}),
-        "album" => {
-            json!({"album_info":album(value, true),"track_list":tracks(array(value,"tracks"),cover,check)?})
-        }
+        // Move normalized values into the envelope. json! serializes borrowed
+        // expressions, duplicating every field of an already-built track list.
+        "track" => Map::from_iter([("track".into(), track(value, "", 0))]).into(),
+        "album" => Map::from_iter([
+            ("album_info".into(), album(value, true)),
+            (
+                "track_list".into(),
+                tracks(array(value, "tracks"), cover, check)?,
+            ),
+        ])
+        .into(),
         "playlist" => {
             let mut info = strings(
                 value,
@@ -413,7 +420,14 @@ fn response(kind: &str, value: &Value, check: &Check<'_>) -> Result<Value, Resol
                 "owner".into(),
                 json!({"name":text(value,"artists"),"images":cover}),
             );
-            json!({"playlist_info":info,"track_list":tracks(array(value,"tracks"),cover,check)?})
+            Map::from_iter([
+                ("playlist_info".into(), info.into()),
+                (
+                    "track_list".into(),
+                    tracks(array(value, "tracks"), cover, check)?,
+                ),
+            ])
+            .into()
         }
         "artist" => {
             let cover = text(value, "image_url");
@@ -439,7 +453,7 @@ fn response(kind: &str, value: &Value, check: &Check<'_>) -> Result<Value, Resol
             if value["listeners"].as_i64().unwrap_or_default() > 0 {
                 info.insert("listeners".into(), value["listeners"].clone());
             }
-            let mut result = json!({"artist_info":info});
+            let mut result = Value::Object(Map::from_iter([("artist_info".into(), info.into())]));
             for key in ["albums", "releases"] {
                 let values = array(value, key);
                 if key == "albums" || !values.is_empty() {
diff --git a/rust_backend/crates/extensions/src/backend/provider_metadata/value_tests.rs b/rust_backend/crates/extensions/src/backend/provider_metadata/value_tests.rs
index ecb718a0..c2b24427 100644
--- a/rust_backend/crates/extensions/src/backend/provider_metadata/value_tests.rs
+++ b/rust_backend/crates/extensions/src/backend/provider_metadata/value_tests.rs
@@ -49,6 +49,41 @@ fn fixture() -> (tempfile::TempDir, Backend) {
     (root, backend)
 }
 
+#[test]
+fn response_envelopes_preserve_json_and_cancellation() {
+    let value = json!({
+        "id": "collection", "name": "音楽 🎵", "artists": "Artist Café",
+        "cover_url": "https://example.invalid/cover.jpg",
+        "tracks": [
+            {"id": "first", "name": "One", "external_links": {"example": "link"}},
+            {"id": "second", "name": "Two", "explicit": true, "track_number": 9},
+        ],
+    });
+    let check = || Ok(());
+    let cover = text(&value, "cover_url");
+    let expected = json!({
+        "album_info": album(&value, true),
+        "track_list": tracks(array(&value, "tracks"), cover, &check).unwrap(),
+    });
+    let actual = response("album", &value, &check).unwrap();
+    assert_eq!(actual.to_string(), expected.to_string());
+    let playlist = response("playlist", &value, &check).unwrap();
+    assert_eq!(playlist["track_list"], expected["track_list"]);
+    assert_eq!(playlist["playlist_info"]["owner"]["name"], "Artist Café");
+    assert_eq!(playlist["track_list"][0]["track_number"], 1);
+    assert_eq!(playlist["track_list"][1]["track_number"], 9);
+    assert_eq!(
+        response("track", &value, &check).unwrap().to_string(),
+        json!({"track": track(&value, "", 0)}).to_string(),
+    );
+    for kind in ["album", "playlist", "artist", "track"] {
+        assert_eq!(
+            response(kind, &value, &|| Err("cancelled".into())),
+            Err(ResolverError::Cancelled("cancelled".into())),
+        );
+    }
+}
+
 #[test]
 fn artist_metadata_preserves_logo_separately_from_portrait() {
     let (_root, backend) = fixture();