diff --git a/apps/web/src/components/pullRequest/usePullRequestDetail.browser.test.tsx b/apps/web/src/components/pullRequest/usePullRequestDetail.browser.test.tsx
new file mode 100644
index 0000000000000..80a21007d9b89
--- /dev/null
+++ b/apps/web/src/components/pullRequest/usePullRequestDetail.browser.test.tsx
@@ -0,0 +1,118 @@
+import {
+  EnvironmentId,
+  ProjectId,
+  SourceControlProviderKind,
+  type PullRequestDetailView,
+} from "@t3tools/contracts";
+import { expect, it, vi } from "vite-plus/test";
+
+const queryState = vi.hoisted(() => ({ data: null as PullRequestDetailView | null }));
+
+vi.mock(import("~/state/query"), async (original) => ({
+  ...(await original()),
+  useEnvironmentQuery: ((query: unknown) => ({
+    data: query === null ? null : queryState.data,
+    dataUpdatedAt: queryState.data ? 1 : 0,
+    isPending: query !== null && queryState.data === null,
+    isSuccess: query !== null && queryState.data !== null,
+    refresh: () => undefined,
+  })) as never,
+}));
+vi.mock(import("~/state/entities"), async (original) => ({
+  ...(await original()),
+  useServerConfigs: () => new Map(),
+}));
+vi.mock(import("~/state/session"), async (original) => ({
+  ...(await original()),
+  useEnvironmentScope: () => true,
+}));
+vi.mock(import("~/state/pullRequests"), async (original) => ({
+  ...(await original()),
+  useSharedPullRequestSummary: () => null,
+}));
+
+import { render } from "../../../test/render";
+import { usePullRequestDetail } from "./usePullRequestDetail";
+
+const liveDetailFixture: PullRequestDetailView = {
+  provider: SourceControlProviderKind.make("github"),
+  projectId: ProjectId.make("project"),
+  projectTitle: "Project",
+  workspaceRoot: "/workspace",
+  repository: "owner/repo",
+  number: 1,
+  title: "Test pull request",
+  body: "Original description",
+  url: "https://github.com/owner/repo/pull/1",
+  author: { login: "author", name: null, avatarUrl: null },
+  viewer: "author",
+  state: "open",
+  isDraft: false,
+  mergeability: "conflicting",
+  additions: 1,
+  deletions: 0,
+  changedFiles: 1,
+  headBranch: "feature",
+  baseBranch: "main",
+  createdAt: "2026-09-01T00:00:00Z",
+  updatedAt: "2026-09-01T00:00:00Z",
+  mergedAt: null,
+  closedAt: null,
+  reviewers: [],
+  labels: [],
+  checks: [{ name: "Unit tests", status: "success", description: null, url: null }],
+  comments: [],
+  commentCount: 0,
+  commentsTruncated: false,
+  reviewThreads: [],
+  commits: [],
+  mergeCapabilities: { merge: false, squash: false, rebase: false },
+  capabilities: {
+    diff: true,
+    comment: false,
+    search: true,
+    actions: [],
+    mergeMethods: [],
+    review: { inlineComment: false, reply: false, resolve: false, verdicts: [] },
+    reviewers: { request: false, listCandidates: false },
+    edit: { changeRequest: true, comment: false },
+  },
+  viewerPermissions: {
+    actions: [],
+    comment: false,
+    resolve: false,
+    verdicts: [],
+    requestReviewers: false,
+  },
+};
+
+function Detail({ number = 1 }: { number?: number }) {
+  const { detail } = usePullRequestDetail(
+    EnvironmentId.make("environment"),
+    { projectId: ProjectId.make("project"), repository: "owner/repo", number },
+    null,
+  );
+  return <p>{detail?.title ?? "Loading pull request"}</p>;
+}
+
+function setup() {
+  queryState.data = null;
+}
+
+it("loads live PR details and changes references when cache storage is denied", async () => {
+  setup();
+  using _storage = vi.spyOn(window, "localStorage", "get").mockImplementation(() => {
+    throw new DOMException("Access to storage is denied", "SecurityError");
+  });
+  await using screen = await render(<Detail />, {
+    // This tests the detail-loading hook, without navigation.
+    router: false,
+  });
+  await expect.element(screen.getByText("Loading pull request")).toBeVisible();
+  queryState.data = liveDetailFixture;
+  await screen.rerender(<Detail />);
+  await expect.element(screen.getByText(liveDetailFixture.title)).toBeVisible();
+  queryState.data = null;
+  await screen.rerender(<Detail number={2} />);
+  await expect.element(screen.getByText("Loading pull request")).toBeVisible();
+});
diff --git a/apps/web/src/components/pullRequest/usePullRequestDetail.ts b/apps/web/src/components/pullRequest/usePullRequestDetail.ts
index 7d6ab0c7a6154..7e5301db4f106 100644
--- a/apps/web/src/components/pullRequest/usePullRequestDetail.ts
+++ b/apps/web/src/components/pullRequest/usePullRequestDetail.ts
@@ -15,6 +15,7 @@ import { useEnvironmentScope } from "~/state/session";
 import {
   newestPullRequestSummary,
   pullRequestEnvironment,
+  pullRequestSnapshotStorage,
   pullRequestListEntryToSummary,
   useSharedPullRequestSummary,
 } from "~/state/pullRequests";
@@ -84,22 +85,14 @@ export function usePullRequestDetail(
     checks: liveDetail?.checks ?? [],
   });
   const [cachedDetail, setCachedDetail] = useState(() =>
-    readPullRequestDetailSnapshot(
-      typeof window === "undefined" ? undefined : window.localStorage,
-      environmentId,
-      reference,
-    ),
+    readPullRequestDetailSnapshot(pullRequestSnapshotStorage(), environmentId, reference),
   );
   const [cachedDetailKey, setCachedDetailKey] = useState(scopeKey);
   if (cachedDetailKey !== scopeKey) {
     setCachedDetailKey(scopeKey);
     setCachedDetail(
       detailQuery.data ??
-        readPullRequestDetailSnapshot(
-          typeof window === "undefined" ? undefined : window.localStorage,
-          environmentId,
-          reference,
-        ),
+        readPullRequestDetailSnapshot(pullRequestSnapshotStorage(), environmentId, reference),
     );
   } else if (detailQuery.data !== null && detailQuery.data !== cachedDetail) {
     setCachedDetail(detailQuery.data);
diff --git a/apps/web/src/hooks/useOpenPanelPullRequestUrl.ts b/apps/web/src/hooks/useOpenPanelPullRequestUrl.ts
index 7be2020a804d9..d16c87d671a4c 100644
--- a/apps/web/src/hooks/useOpenPanelPullRequestUrl.ts
+++ b/apps/web/src/hooks/useOpenPanelPullRequestUrl.ts
@@ -8,7 +8,7 @@ import {
 import { projectChangeRequestUrl } from "@t3tools/client-runtime/change-request-links";
 import { selectActiveRightPanelSurface, useRightPanelStore } from "../rightPanelStore";
 import { useProject } from "../state/entities";
-import { pullRequestEnvironment } from "../state/pullRequests";
+import { pullRequestEnvironment, pullRequestSnapshotStorage } from "../state/pullRequests";
 import { useEnvironmentQuery } from "../state/query";
 import { useSupportsMultiplePullRequests } from "./useSupportsMultiplePullRequests";
 
@@ -61,11 +61,7 @@ export function useOpenPanelPullRequestUrl(threadRef: ScopedThreadRef | null) {
   // Keep all reference/project reads before the query hook to preserve caching of reference and its detail atom.
   const cachedDetail =
     reference && environmentId
-      ? readPullRequestDetailSnapshot(
-          typeof window === "undefined" ? undefined : window.localStorage,
-          environmentId,
-          reference,
-        )
+      ? readPullRequestDetailSnapshot(pullRequestSnapshotStorage(), environmentId, reference)
       : null;
   const fallbackUrl = reference
     ? (requestedReference?.url ??
diff --git a/apps/web/src/state/pullRequests.ts b/apps/web/src/state/pullRequests.ts
index 13d71301e2035..7120a366367aa 100644
--- a/apps/web/src/state/pullRequests.ts
+++ b/apps/web/src/state/pullRequests.ts
@@ -222,7 +222,7 @@ function observePullRequestSummary(
 }
 
 // Reading localStorage throws where the browser blocks storage; that must not break the page.
-function snapshotStorage(): Storage | undefined {
+export function pullRequestSnapshotStorage(): Storage | undefined {
   if (typeof window === "undefined") return undefined;
   try {
     return window.localStorage;
@@ -366,14 +366,14 @@ export function restorePullRequestList(
 export function restoredPullRequestList(
   targets: ReadonlyArray<EnvironmentQueryTarget<PullRequestListInput>>,
 ): MergedPullRequestList | null {
-  return restorePullRequestList(snapshotStorage(), targets);
+  return restorePullRequestList(pullRequestSnapshotStorage(), targets);
 }
 
 // Answers are stamped on arrival: older servers leave no other ordering for same-dated reads.
 export const pullRequestEnvironment = createPullRequestEnvironmentAtoms(connectionAtomRuntime, {
   list: ({ environmentId, input }, answer, registry) =>
     Effect.map(Clock.currentTimeMillis, (observedAt) => {
-      rememberPullRequestListAnswer(snapshotStorage(), { environmentId, input }, answer);
+      rememberPullRequestListAnswer(pullRequestSnapshotStorage(), { environmentId, input }, answer);
       for (const entry of answer.entries) {
         observePullRequestSummary(
           registry,
@@ -387,7 +387,7 @@ export const pullRequestEnvironment = createPullRequestEnvironmentAtoms(connecti
     Effect.map(Clock.currentTimeMillis, (at) => {
       // Only fresh reads seed the cold-start snapshot; a stale one could replace a newer record.
       if (input.allowStale === false) {
-        writePullRequestDetailSnapshot(snapshotStorage(), environmentId, input, detail);
+        writePullRequestDetailSnapshot(pullRequestSnapshotStorage(), environmentId, input, detail);
       }
       observePullRequestSummary(
         registry,