diff --git a/apps/desktop/src/features/score/scoreStorage.bench.ts b/apps/desktop/src/features/score/scoreStorage.bench.ts
new file mode 100644
index 000000000..d9b62d3c8
--- /dev/null
+++ b/apps/desktop/src/features/score/scoreStorage.bench.ts
@@ -0,0 +1,46 @@
+import { bench, describe } from "vitest";
+
+/** Documented. */
+function validateOld(response: unknown[]) {
+  if (Array.isArray(response) && response.every((byte) => typeof byte === "number")) {
+    return Uint8Array.from(response as number[]);
+  }
+  throw new Error("invalid");
+}
+
+/** Documented. */
+function validateNew(response: unknown[]) {
+  if (Array.isArray(response)) {
+    const len = response.length;
+    const arr = new Uint8Array(len);
+    let isValid = true;
+    for (let i = 0; i < len; i++) {
+      const byte = response[i];
+      if (typeof byte !== "number" || !Number.isInteger(byte) || byte < 0 || byte > 255) {
+        isValid = false;
+        break;
+      }
+      arr[i] = byte;
+    }
+    if (isValid) {
+      return arr;
+    }
+  }
+  throw new Error("invalid");
+}
+
+describe("PDF byte array processing", () => {
+  const size = 5_000_000;
+  const payload = new Array(size);
+  for (let i = 0; i < size; i++) {
+    payload[i] = i % 256;
+  }
+
+  bench("legacy Array.from and every", () => {
+    validateOld(payload);
+  });
+
+  bench("single pass pre-allocated loop", () => {
+    validateNew(payload);
+  });
+});
diff --git a/apps/desktop/src/features/score/scoreStorage.test.ts b/apps/desktop/src/features/score/scoreStorage.test.ts
index 0feec199e..af83b8312 100644
--- a/apps/desktop/src/features/score/scoreStorage.test.ts
+++ b/apps/desktop/src/features/score/scoreStorage.test.ts
@@ -7,6 +7,7 @@ type TauriWindow = Window & {
 };
 
 const BRIDGE_UNAVAILABLE_MESSAGE = "Score PDFs are only available in the desktop app.";
+const INVALID_RESPONSE_MESSAGE = "Invalid score bridge response";
 
 describe("scoreStorage bridge resolution", () => {
   afterEach(() => {
@@ -32,4 +33,35 @@ describe("scoreStorage bridge resolution", () => {
       BRIDGE_UNAVAILABLE_MESSAGE
     );
   });
+
+  it("preserves exact bytes from a valid bridge array", async () => {
+    (window as TauriWindow).__TAURI_INVOKE__ = vi.fn().mockResolvedValue([0, 1, 255]);
+
+    await expect(readScorePdf("project-1", "score-1")).resolves.toEqual(
+      new Uint8Array([0, 1, 255])
+    );
+  });
+
+  it("accepts an empty bridge array", async () => {
+    (window as TauriWindow).__TAURI_INVOKE__ = vi.fn().mockResolvedValue([]);
+
+    await expect(readScorePdf("project-1", "score-1")).resolves.toEqual(new Uint8Array());
+  });
+
+  it.each([
+    ["NaN", Number.NaN],
+    ["Infinity", Number.POSITIVE_INFINITY],
+    ["negative", -1],
+    ["fractional", 1.5],
+    ["greater than 255", 256],
+    ["non-number", "1"]
+  ])("rejects a %s bridge byte", async (_label, invalidByte) => {
+    (window as TauriWindow).__TAURI_INVOKE__ = vi
+      .fn()
+      .mockResolvedValue([0, invalidByte, 255]);
+
+    await expect(readScorePdf("project-1", "score-1")).rejects.toThrow(
+      INVALID_RESPONSE_MESSAGE
+    );
+  });
 });
diff --git a/apps/desktop/src/features/score/scoreStorage.ts b/apps/desktop/src/features/score/scoreStorage.ts
index 492f12591..b77764671 100644
--- a/apps/desktop/src/features/score/scoreStorage.ts
+++ b/apps/desktop/src/features/score/scoreStorage.ts
@@ -91,8 +91,21 @@ export async function readScorePdf(projectId: string, scoreId: string): Promise<
   if (response instanceof ArrayBuffer) {
     return new Uint8Array(response);
   }
-  if (Array.isArray(response) && response.every((byte) => typeof byte === "number")) {
-    return Uint8Array.from(response as number[]);
+  if (Array.isArray(response)) {
+    const len = response.length;
+    const arr = new Uint8Array(len);
+    let isValid = true;
+    for (let i = 0; i < len; i++) {
+      const byte = response[i];
+      if (typeof byte !== "number" || !Number.isInteger(byte) || byte < 0 || byte > 255) {
+        isValid = false;
+        break;
+      }
+      arr[i] = byte;
+    }
+    if (isValid) {
+      return arr;
+    }
   }
 
   throw new Error(INVALID_RESPONSE_MESSAGE);
diff --git a/services/analysis-engine/tests/test_supply_chain_policy.py b/services/analysis-engine/tests/test_supply_chain_policy.py
index 1d8224c5a..6a0853944 100644
--- a/services/analysis-engine/tests/test_supply_chain_policy.py
+++ b/services/analysis-engine/tests/test_supply_chain_policy.py
@@ -1275,9 +1275,7 @@ def test_workflow_concurrency_cancels_only_superseded_pr_heads() -> None:
         workflow = (workflows_dir / workflow_name).read_text(encoding="utf-8")
         assert "concurrency:" in workflow, workflow_name
         assert "cancel-in-progress: false" in workflow, workflow_name
-        assert "contents: read" in workflow or "permissions: read-all" in workflow, (
-            workflow_name
-        )
+        assert "contents: read" in workflow or "permissions: read-all" in workflow, workflow_name
 
     assert "pull_request:" not in (workflows_dir / "release.yml").read_text(encoding="utf-8")