diff --git a/.Jules/palette.md b/.Jules/palette.md
index 5c1c16989..354340528 100644
--- a/.Jules/palette.md
+++ b/.Jules/palette.md
@@ -37,3 +37,6 @@
 ## 2026-07-02 - Inline clear buttons preserve focus
 **Learning:** Inline clear buttons often unmount immediately after clearing state, which can drop keyboard focus to the document body.
 **Action:** Move focus back to the owning input before clearing state, and cover the behavior with a DOM focus test.
+## 2026-08-04 - Accessible disabled buttons in test suites
+**Learning:** When testing accessible disabled buttons that use `aria-disabled="true"`, Jest-DOM's `.toBeDisabled()` will fail because it strictly checks for the native HTML `disabled` attribute.
+**Action:** Instead, query the button (e.g., `screen.getByRole("button", { name: ... })`) and use `.toHaveAttribute("aria-disabled", "true")` to assert its state.
diff --git a/apps/desktop/src/features/score/ScoreView.test.tsx b/apps/desktop/src/features/score/ScoreView.test.tsx
index de4ccb95c..7ad035f19 100644
--- a/apps/desktop/src/features/score/ScoreView.test.tsx
+++ b/apps/desktop/src/features/score/ScoreView.test.tsx
@@ -96,7 +96,7 @@ describe("ScoreView", () => {
 
     expect(screen.getByText("Scores attach to the active analysis project.")).toBeInTheDocument();
     expect(screen.getByRole("button", { name: "Add score" })).toBeDisabled();
-    expect(screen.getByRole("button", { name: "Open score: opener.pdf" })).toBeDisabled();
+    expect(screen.getByRole("button", { name: "Open score: opener.pdf" })).toHaveAttribute("aria-disabled", "true");
     expect(screen.getByRole("button", { name: "Remove: opener.pdf" })).toBeDisabled();
 
     fireEvent.click(screen.getByRole("button", { name: "Open score: opener.pdf" }));
diff --git a/apps/desktop/src/features/score/ScoreView.tsx b/apps/desktop/src/features/score/ScoreView.tsx
index 72732450f..9d9afa47d 100644
--- a/apps/desktop/src/features/score/ScoreView.tsx
+++ b/apps/desktop/src/features/score/ScoreView.tsx
@@ -184,10 +184,11 @@ export function ScoreView({ song, projectId, onSongUpdate }: ScoreViewProps) {
                     <button
                       type="button"
                       onClick={projectId ? () => void openAttachment(projectId, attachment) : undefined}
-                      disabled={!projectId}
+                      aria-disabled={!projectId ? "true" : undefined}
                       aria-current={selected?.id === attachment.id ? "true" : undefined}
                       aria-label={`${t("scoreOpen")}: ${attachment.fileName}`}
-                      className="flex min-h-10 min-w-0 flex-1 items-center gap-2 text-left text-sm font-semibold text-slate-100 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-cyan-300 disabled:cursor-not-allowed disabled:opacity-60"
+                      title={!projectId ? t("scoreRequiresProject") : `${t("scoreOpen")}: ${attachment.fileName}`}
+                      className="flex min-h-10 min-w-0 flex-1 items-center gap-2 text-left text-sm font-semibold text-slate-100 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-cyan-300 aria-disabled:cursor-not-allowed aria-disabled:opacity-60"
                     >
                       <FileMusic className="size-4 shrink-0 text-cyan-300" aria-hidden="true" />
                       <span className="truncate">{attachment.fileName}</span>
@@ -198,6 +199,7 @@ export function ScoreView({ song, projectId, onSongUpdate }: ScoreViewProps) {
                       onClick={projectId ? () => void handleRemove(projectId, attachment) : undefined}
                       disabled={!projectId}
                       aria-label={`${t("scoreRemove")}: ${attachment.fileName}`}
+                      title={!projectId ? t("scoreRequiresProject") : `${t("scoreRemove")}: ${attachment.fileName}`}
                       className="size-10 border-rose-300/25 text-rose-200 hover:bg-rose-400/10"
                     >
                       <Trash2 className="size-4" aria-hidden="true" />
diff --git a/apps/desktop/src/features/score/ScoreViewer.tsx b/apps/desktop/src/features/score/ScoreViewer.tsx
index 82692469e..35819e418 100644
--- a/apps/desktop/src/features/score/ScoreViewer.tsx
+++ b/apps/desktop/src/features/score/ScoreViewer.tsx
@@ -258,6 +258,7 @@ export function ScoreViewer({ data, fileName, onStatusChange }: ScoreViewerProps
               size="icon-lg"
               className="size-12"
               aria-label={t("scoreViewerZoomOut")}
+              title={t("scoreViewerZoomOut")}
               onClick={zoomOut}
             >
               <ZoomOut aria-hidden="true" />
@@ -267,6 +268,7 @@ export function ScoreViewer({ data, fileName, onStatusChange }: ScoreViewerProps
               size="icon-lg"
               className="size-12"
               aria-label={t("scoreViewerZoomIn")}
+              title={t("scoreViewerZoomIn")}
               onClick={zoomIn}
             >
               <ZoomIn aria-hidden="true" />
@@ -292,6 +294,7 @@ export function ScoreViewer({ data, fileName, onStatusChange }: ScoreViewerProps
             size="icon-lg"
             className="size-14"
             aria-label={t("scoreViewerPrevPage")}
+            title={t("scoreViewerPrevPage")}
             disabled={pageNumber <= 1}
             onClick={goToPreviousPage}
           >
@@ -305,6 +308,7 @@ export function ScoreViewer({ data, fileName, onStatusChange }: ScoreViewerProps
             size="icon-lg"
             className="size-14"
             aria-label={t("scoreViewerNextPage")}
+            title={t("scoreViewerNextPage")}
             disabled={pageNumber >= pageCount}
             onClick={goToNextPage}
           >
diff --git a/package-lock.json b/package-lock.json
index cf1c991c1..ff7604e43 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -955,7 +955,6 @@
       "os": [
         "aix"
       ],
-      "peer": true,
       "engines": {
         "node": ">=18"
       }
@@ -973,7 +972,6 @@
       "os": [
         "android"
       ],
-      "peer": true,
       "engines": {
         "node": ">=18"
       }
@@ -991,7 +989,6 @@
       "os": [
         "android"
       ],
-      "peer": true,
       "engines": {
         "node": ">=18"
       }
@@ -1009,7 +1006,6 @@
       "os": [
         "android"
       ],
-      "peer": true,
       "engines": {
         "node": ">=18"
       }
@@ -1027,7 +1023,6 @@
       "os": [
         "darwin"
       ],
-      "peer": true,
       "engines": {
         "node": ">=18"
       }
@@ -1045,7 +1040,6 @@
       "os": [
         "darwin"
       ],
-      "peer": true,
       "engines": {
         "node": ">=18"
       }
@@ -1063,7 +1057,6 @@
       "os": [
         "freebsd"
       ],
-      "peer": true,
       "engines": {
         "node": ">=18"
       }
@@ -1081,7 +1074,6 @@
       "os": [
         "freebsd"
       ],
-      "peer": true,
       "engines": {
         "node": ">=18"
       }
@@ -1099,7 +1091,6 @@
       "os": [
         "linux"
       ],
-      "peer": true,
       "engines": {
         "node": ">=18"
       }
@@ -1117,7 +1108,6 @@
       "os": [
         "linux"
       ],
-      "peer": true,
       "engines": {
         "node": ">=18"
       }
@@ -1135,7 +1125,6 @@
       "os": [
         "linux"
       ],
-      "peer": true,
       "engines": {
         "node": ">=18"
       }
@@ -1153,7 +1142,6 @@
       "os": [
         "linux"
       ],
-      "peer": true,
       "engines": {
         "node": ">=18"
       }
@@ -1171,7 +1159,6 @@
       "os": [
         "linux"
       ],
-      "peer": true,
       "engines": {
         "node": ">=18"
       }
@@ -1189,7 +1176,6 @@
       "os": [
         "linux"
       ],
-      "peer": true,
       "engines": {
         "node": ">=18"
       }
@@ -1207,7 +1193,6 @@
       "os": [
         "linux"
       ],
-      "peer": true,
       "engines": {
         "node": ">=18"
       }
@@ -1225,7 +1210,6 @@
       "os": [
         "linux"
       ],
-      "peer": true,
       "engines": {
         "node": ">=18"
       }
@@ -1243,7 +1227,6 @@
       "os": [
         "linux"
       ],
-      "peer": true,
       "engines": {
         "node": ">=18"
       }
@@ -1261,7 +1244,6 @@
       "os": [
         "netbsd"
       ],
-      "peer": true,
       "engines": {
         "node": ">=18"
       }
@@ -1279,7 +1261,6 @@
       "os": [
         "netbsd"
       ],
-      "peer": true,
       "engines": {
         "node": ">=18"
       }
@@ -1297,7 +1278,6 @@
       "os": [
         "openbsd"
       ],
-      "peer": true,
       "engines": {
         "node": ">=18"
       }
@@ -1315,7 +1295,6 @@
       "os": [
         "openbsd"
       ],
-      "peer": true,
       "engines": {
         "node": ">=18"
       }
@@ -1333,7 +1312,6 @@
       "os": [
         "openharmony"
       ],
-      "peer": true,
       "engines": {
         "node": ">=18"
       }
@@ -1351,7 +1329,6 @@
       "os": [
         "sunos"
       ],
-      "peer": true,
       "engines": {
         "node": ">=18"
       }
@@ -1369,7 +1346,6 @@
       "os": [
         "win32"
       ],
-      "peer": true,
       "engines": {
         "node": ">=18"
       }
@@ -1387,7 +1363,6 @@
       "os": [
         "win32"
       ],
-      "peer": true,
       "engines": {
         "node": ">=18"
       }
@@ -1405,7 +1380,6 @@
       "os": [
         "win32"
       ],
-      "peer": true,
       "engines": {
         "node": ">=18"
       }
@@ -7179,9 +7153,9 @@
       }
     },
     "node_modules/undici": {
-      "version": "7.28.0",
-      "resolved": "https://registry.npmjs.org/undici/-/undici-7.28.0.tgz",
-      "integrity": "sha512-cRZYrTDwWznlnRiPjggAGxZXanty6M8RV1ff8Wm4LWXBp7/IG8v5DnOm74DtUBp9OONpK75YlPnIjQqX0dBDtA==",
+      "version": "7.29.0",
+      "resolved": "https://registry.npmjs.org/undici/-/undici-7.29.0.tgz",
+      "integrity": "sha512-IDxfleLmmbSskfWSUATiN1nfn2rDuvnMOqb5CWR92iIfojA0Ud+ulOAAEQ57LPr9rWmsreUyf5lwyao+7GNNVw==",
       "dev": true,
       "license": "MIT",
       "engines": {