diff --git a/ui/src/App.tsx b/ui/src/App.tsx
index dd0bbff61df..8baf908d725 100644
--- a/ui/src/App.tsx
+++ b/ui/src/App.tsx
@@ -24,6 +24,7 @@ import { ExecutionWorkspaceDetail } from "./pages/ExecutionWorkspaceDetail";
 import { Goals } from "./pages/Goals";
 import { Artifacts } from "./pages/Artifacts";
 import { Documents } from "./pages/Documents";
+import { DocumentDetail } from "./pages/DocumentDetail";
 import { GoalDetail } from "./pages/GoalDetail";
 import { Approvals } from "./pages/Approvals";
 import { ApprovalDetail } from "./pages/ApprovalDetail";
@@ -130,6 +131,7 @@ function boardRoutes() {
       <Route path="goals" element={<Goals />} />
       <Route path="goals/:goalId" element={<GoalDetail />} />
       <Route path="documents" element={<Documents />} />
+      <Route path="documents/:documentId" element={<DocumentDetail />} />
       <Route path="artifacts" element={<Artifacts />} />
       <Route path="approvals" element={<Navigate to="/approvals/pending" replace />} />
       <Route path="approvals/pending" element={<Approvals />} />
diff --git a/ui/src/api/document-reviews.ts b/ui/src/api/document-reviews.ts
new file mode 100644
index 00000000000..d51831215b0
--- /dev/null
+++ b/ui/src/api/document-reviews.ts
@@ -0,0 +1,115 @@
+import type {
+  AcceptDocumentSuggestionRequest,
+  CompanyDocument,
+  CreateDocumentReviewCommentRequest,
+  CreateDocumentReviewThreadRequest,
+  CreateDocumentSuggestionCommentRequest,
+  CreateDocumentSuggestionRequest,
+  DocumentReviewComment,
+  DocumentReviewIndex,
+  DocumentReviewThreadStatus,
+  DocumentReviewThreadWithComments,
+  DocumentSuggestion,
+  DocumentSuggestionComment,
+  RejectDocumentSuggestionRequest,
+} from "@paperclipai/shared";
+import { api } from "./client";
+
+export type DocumentReviewIndexStatus = "open" | "all";
+
+/**
+ * The accept endpoint returns the resulting revision + the updated document so
+ * the caller can refresh the body and open a diff. We keep the shape loose for
+ * the fields the detail view actually consumes.
+ */
+export interface AcceptDocumentSuggestionResult {
+  suggestion: DocumentSuggestion;
+  document: CompanyDocument;
+  revision: { id: string; revisionNumber: number };
+}
+
+/**
+ * Document review surface (anchored comments live in `document-annotations`;
+ * this module covers the *review-index*, document-level review threads, and
+ * suggested edits — the pieces the detail/review view layers on top).
+ */
+export const documentReviewsApi = {
+  reviewIndex: (
+    issueId: string,
+    key: string,
+    options: { rev?: number; status?: DocumentReviewIndexStatus; includeComments?: boolean } = {},
+  ) => {
+    const params = new URLSearchParams();
+    if (options.rev !== undefined) params.set("rev", String(options.rev));
+    if (options.status) params.set("status", options.status);
+    if (options.includeComments) params.set("includeComments", "true");
+    const qs = params.toString();
+    return api.get<DocumentReviewIndex>(
+      `/issues/${issueId}/documents/${encodeURIComponent(key)}/review-index${qs ? `?${qs}` : ""}`,
+    );
+  },
+
+  // --- Document-level / overall review threads (anchor: null) ----------------
+  createReviewThread: (issueId: string, key: string, data: CreateDocumentReviewThreadRequest) =>
+    api.post<DocumentReviewThreadWithComments>(
+      `/issues/${issueId}/documents/${encodeURIComponent(key)}/review-comments`,
+      data,
+    ),
+  addReviewComment: (
+    issueId: string,
+    key: string,
+    threadId: string,
+    data: CreateDocumentReviewCommentRequest,
+  ) =>
+    api.post<DocumentReviewComment>(
+      `/issues/${issueId}/documents/${encodeURIComponent(key)}/review-comments/${threadId}/comments`,
+      data,
+    ),
+  updateReviewThreadStatus: (
+    issueId: string,
+    key: string,
+    threadId: string,
+    status: DocumentReviewThreadStatus,
+  ) =>
+    api.patch<DocumentReviewThreadWithComments>(
+      `/issues/${issueId}/documents/${encodeURIComponent(key)}/review-comments/${threadId}`,
+      { status },
+    ),
+
+  // --- Suggested edits -------------------------------------------------------
+  createSuggestion: (issueId: string, key: string, data: CreateDocumentSuggestionRequest) =>
+    api.post<DocumentSuggestion>(
+      `/issues/${issueId}/documents/${encodeURIComponent(key)}/suggestions`,
+      data,
+    ),
+  addSuggestionComment: (
+    issueId: string,
+    key: string,
+    suggestionId: string,
+    data: CreateDocumentSuggestionCommentRequest,
+  ) =>
+    api.post<DocumentSuggestionComment>(
+      `/issues/${issueId}/documents/${encodeURIComponent(key)}/suggestions/${suggestionId}/comments`,
+      data,
+    ),
+  acceptSuggestion: (
+    issueId: string,
+    key: string,
+    suggestionId: string,
+    data: AcceptDocumentSuggestionRequest,
+  ) =>
+    api.post<AcceptDocumentSuggestionResult>(
+      `/issues/${issueId}/documents/${encodeURIComponent(key)}/suggestions/${suggestionId}/accept`,
+      data,
+    ),
+  rejectSuggestion: (
+    issueId: string,
+    key: string,
+    suggestionId: string,
+    data: RejectDocumentSuggestionRequest,
+  ) =>
+    api.post<DocumentSuggestion>(
+      `/issues/${issueId}/documents/${encodeURIComponent(key)}/suggestions/${suggestionId}/reject`,
+      data,
+    ),
+};
diff --git a/ui/src/components/DocumentAnnotationLayer.tsx b/ui/src/components/DocumentAnnotationLayer.tsx
index 6859922ab60..7a6567591a7 100644
--- a/ui/src/components/DocumentAnnotationLayer.tsx
+++ b/ui/src/components/DocumentAnnotationLayer.tsx
@@ -48,6 +48,18 @@ export interface AnnotationLayerProps {
    * pending anchor for the keyboard shortcut path.
    */
   captureSelectionRequestId?: number;
+  /**
+   * Optional override for the floating selection toolbar contents. When provided,
+   * it replaces the built-in "Comment" button so callers (e.g. the document
+   * detail view) can offer richer actions like "Suggest edit" while reusing the
+   * layer's caret-anchored positioning. `addComment` runs the same flow the
+   * default button does; `clear` drops the pending selection.
+   */
+  renderSelectionToolbar?: (args: {
+    anchor: PendingAnchor;
+    addComment: () => void;
+    clear: () => void;
+  }) => React.ReactNode;
 }
 
 interface HighlightRect {
@@ -203,6 +215,7 @@ export function DocumentAnnotationLayer({
   newCommentDisabledReason = null,
   hideResolved = true,
   captureSelectionRequestId,
+  renderSelectionToolbar,
 }: AnnotationLayerProps) {
   const [highlightRects, setHighlightRects] = useState<HighlightRect[]>([]);
   const [toolbarPosition, setToolbarPosition] = useState<ToolbarPosition | null>(null);
@@ -492,20 +505,28 @@ export function DocumentAnnotationLayer({
               style={{ top: toolbarPosition.top, left: toolbarPosition.left }}
               onMouseDown={(event) => event.preventDefault()}
             >
-              <Button
-                type="button"
-                size="sm"
-                variant="ghost"
-                className="h-7 gap-1 px-2 text-xs"
-                onClick={handleAddComment}
-                disabled={newCommentDisabled}
-                title={newCommentDisabled
-                  ? newCommentDisabledReason ?? undefined
-                  : "Add comment on selection (⌘⇧M)"}
-              >
-                <MessageSquarePlus className="h-3.5 w-3.5" aria-hidden="true" />
-                Comment
-              </Button>
+              {renderSelectionToolbar ? (
+                renderSelectionToolbar({
+                  anchor: pendingAnchor,
+                  addComment: handleAddComment,
+                  clear: () => onPendingAnchorChange(null),
+                })
+              ) : (
+                <Button
+                  type="button"
+                  size="sm"
+                  variant="ghost"
+                  className="h-7 gap-1 px-2 text-xs"
+                  onClick={handleAddComment}
+                  disabled={newCommentDisabled}
+                  title={newCommentDisabled
+                    ? newCommentDisabledReason ?? undefined
+                    : "Add comment on selection (⌘⇧M)"}
+                >
+                  <MessageSquarePlus className="h-3.5 w-3.5" aria-hidden="true" />
+                  Comment
+                </Button>
+              )}
             </div>
           ) : null}
         </div>
diff --git a/ui/src/components/documents/DocumentReviewRail.test.tsx b/ui/src/components/documents/DocumentReviewRail.test.tsx
new file mode 100644
index 00000000000..96b4ce0e356
--- /dev/null
+++ b/ui/src/components/documents/DocumentReviewRail.test.tsx
@@ -0,0 +1,264 @@
+// @vitest-environment jsdom
+
+import { flushSync } from "react-dom";
+import { createRoot, type Root } from "react-dom/client";
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+import type {
+  DocumentReviewIndex,
+  DocumentSuggestionWithComments,
+} from "@paperclipai/shared";
+import { DocumentReviewRail } from "./DocumentReviewRail";
+
+vi.mock("@/components/MarkdownBody", () => ({
+  MarkdownBody: ({ children }: { children: string }) => <p>{children}</p>,
+}));
+
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+(globalThis as any).IS_REACT_ACT_ENVIRONMENT = true;
+
+async function act(callback: () => void | Promise<void>) {
+  let result: void | Promise<void> = undefined;
+  flushSync(() => {
+    result = callback();
+  });
+  await result;
+}
+
+let container: HTMLDivElement;
+let root: Root;
+
+beforeEach(() => {
+  container = document.createElement("div");
+  document.body.appendChild(container);
+  root = createRoot(container);
+});
+
+afterEach(() => {
+  act(() => root.unmount());
+  container.remove();
+});
+
+function makeSuggestion(overrides: Partial<DocumentSuggestionWithComments> = {}): DocumentSuggestionWithComments {
+  return {
+    id: "sug-1",
+    companyId: "c1",
+    issueId: "i1",
+    documentId: "d1",
+    documentKey: "spec",
+    kind: "insertion",
+    status: "pending",
+    anchorState: "active",
+    anchorConfidence: "exact",
+    originalRevisionId: "rev-1",
+    originalRevisionNumber: 1,
+    currentRevisionId: "rev-1",
+    currentRevisionNumber: 1,
+    selectedText: "anchor",
+    proposedText: "added text",
+    insertionPosition: "after",
+    prefixText: "",
+    suffixText: "",
+    normalizedStart: 0,
+    normalizedEnd: 6,
+    markdownStart: 0,
+    markdownEnd: 6,
+    anchorSelector: { quote: { exact: "anchor", prefix: "", suffix: "" }, position: { normalizedStart: 0, normalizedEnd: 6, markdownStart: 0, markdownEnd: 6 } },
+    createdByAgentId: "agent-1",
+    createdByUserId: null,
+    acceptedByAgentId: null,
+    acceptedByUserId: null,
+    acceptedAt: null,
+    acceptedRevisionId: null,
+    rejectedByAgentId: null,
+    rejectedByUserId: null,
+    rejectedAt: null,
+    createdAt: new Date("2026-06-01T00:00:00Z"),
+    updatedAt: new Date("2026-06-01T00:00:00Z"),
+    comments: [],
+    ...overrides,
+  };
+}
+
+function makeIndex(overrides: Partial<DocumentReviewIndex> = {}): DocumentReviewIndex {
+  return {
+    issueId: "i1",
+    documentId: "d1",
+    documentKey: "spec",
+    latestRevisionId: "rev-1",
+    latestRevisionNumber: 1,
+    counts: {
+      unresolved: 1,
+      openAnchoredThreads: 1,
+      openReviewThreads: 1,
+      pendingSuggestions: 1,
+      resolvedAnchoredThreads: 0,
+      resolvedReviewThreads: 0,
+      acceptedSuggestions: 0,
+      rejectedSuggestions: 0,
+      staleAnchors: 0,
+      orphanedAnchors: 0,
+    },
+    annotationThreads: [
+      {
+        id: "thread-1",
+        companyId: "c1",
+        issueId: "i1",
+        documentId: "d1",
+        documentKey: "spec",
+        status: "open",
+        anchorState: "active",
+        anchorConfidence: "exact",
+        originalRevisionId: "rev-1",
+        originalRevisionNumber: 1,
+        currentRevisionId: "rev-1",
+        currentRevisionNumber: 1,
+        selectedText: "anchored phrase",
+        prefixText: "",
+        suffixText: "",
+        normalizedStart: 0,
+        normalizedEnd: 5,
+        markdownStart: 0,
+        markdownEnd: 5,
+        anchorSelector: { quote: { exact: "anchored phrase", prefix: "", suffix: "" }, position: { normalizedStart: 0, normalizedEnd: 5, markdownStart: 0, markdownEnd: 5 } },
+        createdByAgentId: "agent-1",
+        createdByUserId: null,
+        resolvedByAgentId: null,
+        resolvedByUserId: null,
+        resolvedAt: null,
+        createdAt: new Date("2026-06-01T00:00:00Z"),
+        updatedAt: new Date("2026-06-01T00:00:00Z"),
+        comments: [
+          {
+            id: "c1",
+            companyId: "c1",
+            threadId: "thread-1",
+            issueId: "i1",
+            documentId: "d1",
+            body: "Worth being explicit here?",
+            authorType: "agent",
+            authorAgentId: "agent-1",
+            authorUserId: null,
+            createdByRunId: null,
+            createdAt: new Date("2026-06-01T00:00:00Z"),
+            updatedAt: new Date("2026-06-01T00:00:00Z"),
+          },
+        ],
+      },
+    ],
+    reviewThreads: [
+      {
+        id: "overall-1",
+        companyId: "c1",
+        issueId: "i1",
+        documentId: "d1",
+        documentKey: "spec",
+        status: "open",
+        createdByAgentId: null,
+        createdByUserId: "user-1",
+        resolvedByAgentId: null,
+        resolvedByUserId: null,
+        resolvedAt: null,
+        createdAt: new Date("2026-06-01T00:00:00Z"),
+        updatedAt: new Date("2026-06-01T00:00:00Z"),
+        comments: [
+          {
+            id: "rc1",
+            companyId: "c1",
+            threadId: "overall-1",
+            issueId: "i1",
+            documentId: "d1",
+            body: "Overall this is close.",
+            authorType: "user",
+            authorAgentId: null,
+            authorUserId: "user-1",
+            createdByRunId: null,
+            createdAt: new Date("2026-06-01T00:00:00Z"),
+            updatedAt: new Date("2026-06-01T00:00:00Z"),
+          },
+        ],
+      },
+    ],
+    suggestions: [makeSuggestion()],
+    ...overrides,
+  };
+}
+
+const baseHandlers = {
+  onReplyThread: vi.fn(),
+  onToggleThreadResolved: vi.fn(),
+  onAcceptSuggestion: vi.fn(),
+  onRejectSuggestion: vi.fn(),
+  onReplySuggestion: vi.fn(),
+};
+
+describe("DocumentReviewRail", () => {
+  it("renders two tabs with counts and the overall + anchored comments", async () => {
+    await act(() =>
+      root.render(
+        <DocumentReviewRail reviewIndex={makeIndex()} canReview canFinishReview latestRevisionId="rev-1" {...baseHandlers} />,
+      ),
+    );
+    const commentsTab = container.querySelector('[data-testid="rail-tab-comments"]');
+    const suggestionsTab = container.querySelector('[data-testid="rail-tab-suggestions"]');
+    expect(commentsTab?.textContent).toContain("Comments (2)");
+    expect(suggestionsTab?.textContent).toContain("Suggestions (1)");
+    // Comments tab is default — shows overall + anchored.
+    expect(container.textContent).toContain("Overall feedback");
+    expect(container.textContent).toContain("anchored phrase");
+  });
+
+  it("renders a SuggestionCard on the Suggestions tab", async () => {
+    await act(() =>
+      root.render(
+        <DocumentReviewRail
+          reviewIndex={makeIndex()}
+          canReview
+          canFinishReview
+          latestRevisionId="rev-1"
+          initialTab="suggestions"
+          {...baseHandlers}
+        />,
+      ),
+    );
+    expect(container.querySelector('[data-testid="suggestion-card-sug-1"]')).not.toBeNull();
+    expect(container.textContent).toContain("added text");
+  });
+
+  it("pins orphaned anchors into a collapsible group when the orphan filter is on", async () => {
+    const index = makeIndex({
+      annotationThreads: [
+        {
+          ...makeIndex().annotationThreads[0],
+          id: "thread-orphan",
+          anchorState: "orphaned",
+          selectedText: "lost anchor",
+        },
+      ],
+    });
+    await act(() =>
+      root.render(
+        <DocumentReviewRail reviewIndex={index} canReview canFinishReview latestRevisionId="rev-1" {...baseHandlers} />,
+      ),
+    );
+    // Enable the orphaned filter chip.
+    await act(() => container.querySelector<HTMLButtonElement>('[data-testid="rail-filter-orphaned"]')!.click());
+    expect(container.querySelector('[data-testid="rail-orphan-group"]')).not.toBeNull();
+    expect(container.textContent).toContain("Orphaned feedback (1)");
+  });
+
+  it("disables Done reviewing for read-only viewers", async () => {
+    await act(() =>
+      root.render(
+        <DocumentReviewRail
+          reviewIndex={makeIndex()}
+          canReview={false}
+          canFinishReview={false}
+          latestRevisionId="rev-1"
+          {...baseHandlers}
+        />,
+      ),
+    );
+    const done = container.querySelector<HTMLButtonElement>('[data-testid="rail-done-reviewing"]');
+    expect(done?.disabled).toBe(true);
+  });
+});
diff --git a/ui/src/components/documents/DocumentReviewRail.tsx b/ui/src/components/documents/DocumentReviewRail.tsx
new file mode 100644
index 00000000000..03cf254fad8
--- /dev/null
+++ b/ui/src/components/documents/DocumentReviewRail.tsx
@@ -0,0 +1,429 @@
+import { useMemo, useState } from "react";
+import type {
+  DocumentReviewIndex,
+  DocumentSuggestionWithComments,
+} from "@paperclipai/shared";
+import { CheckCircle2, MessageSquarePlus } from "lucide-react";
+import { Badge } from "@/components/ui/badge";
+import { Button } from "@/components/ui/button";
+import { Textarea } from "@/components/ui/textarea";
+import { Tabs, TabsContent, TabsList, TabsTrigger } from "@/components/ui/tabs";
+import { Sheet, SheetContent, SheetTitle } from "@/components/ui/sheet";
+import {
+  Tooltip,
+  TooltipContent,
+  TooltipProvider,
+  TooltipTrigger,
+} from "@/components/ui/tooltip";
+import { cn } from "@/lib/utils";
+import type { ReviewAuthorMaps } from "@/lib/document-review-authors";
+import { DocumentThreadCard, type RailThread } from "./DocumentThreadCard";
+import { SuggestionCard } from "./SuggestionCard";
+
+type ReviewFilter = "open" | "resolved" | "stale" | "orphaned";
+
+const FILTERS: { id: ReviewFilter; label: string }[] = [
+  { id: "open", label: "Open" },
+  { id: "resolved", label: "Resolved" },
+  { id: "stale", label: "Stale" },
+  { id: "orphaned", label: "Orphaned" },
+];
+
+export interface DocumentReviewRailProps {
+  reviewIndex?: DocumentReviewIndex;
+  loading?: boolean;
+  /** Viewer can reply/resolve/accept/reject. */
+  canReview: boolean;
+  /** Viewer has edit rights (gates the Done reviewing CTA). */
+  canFinishReview?: boolean;
+  doneReviewingDisabledReason?: string | null;
+  latestRevisionId: string | null;
+  authorMaps?: ReviewAuthorMaps;
+  focusedThreadId?: string | null;
+  onFocusThread?: (threadId: string) => void;
+  onReplyThread: (thread: RailThread, body: string) => Promise<void> | void;
+  onToggleThreadResolved: (thread: RailThread, resolved: boolean) => Promise<void> | void;
+  onAddOverallComment?: (body: string) => Promise<void> | void;
+  onAcceptSuggestion: (suggestion: DocumentSuggestionWithComments) => Promise<void> | void;
+  onRejectSuggestion: (suggestion: DocumentSuggestionWithComments, reason: string) => Promise<void> | void;
+  onReplySuggestion: (suggestion: DocumentSuggestionWithComments, body: string) => Promise<void> | void;
+  onViewSuggestionDiff?: (suggestion: DocumentSuggestionWithComments) => void;
+  onDoneReviewing?: () => void;
+  /** Which tab to open first (e.g. when a deep link targets a suggestion). */
+  initialTab?: "comments" | "suggestions";
+  /** Mobile: render inside a bottom Sheet. */
+  isMobile?: boolean;
+  open?: boolean;
+  onOpenChange?: (open: boolean) => void;
+  className?: string;
+}
+
+export function DocumentReviewRail(props: DocumentReviewRailProps) {
+  if (props.isMobile) {
+    return (
+      <Sheet open={props.open ?? false} onOpenChange={props.onOpenChange ?? (() => {})}>
+        <SheetContent
+          side="bottom"
+          showCloseButton={false}
+          className="z-[60] flex max-h-[88vh] flex-col rounded-t-lg border-t border-border bg-popover p-0 text-popover-foreground shadow-2xl"
+        >
+          <SheetTitle className="sr-only">Document review</SheetTitle>
+          <div className="mx-auto mt-2 h-1.5 w-12 shrink-0 rounded-full bg-muted-foreground/30" aria-hidden="true" />
+          <ReviewRailBody {...props} />
+        </SheetContent>
+      </Sheet>
+    );
+  }
+
+  return (
+    <aside
+      role="complementary"
+      aria-label="Document review"
+      data-testid="document-review-rail"
+      className={cn("flex h-full w-full flex-col overflow-hidden border-l border-border bg-card", props.className)}
+    >
+      <ReviewRailBody {...props} />
+    </aside>
+  );
+}
+
+function ReviewRailBody({
+  reviewIndex,
+  loading,
+  canReview,
+  canFinishReview,
+  doneReviewingDisabledReason,
+  latestRevisionId,
+  authorMaps,
+  focusedThreadId,
+  onFocusThread,
+  onReplyThread,
+  onToggleThreadResolved,
+  onAddOverallComment,
+  onAcceptSuggestion,
+  onRejectSuggestion,
+  onReplySuggestion,
+  onViewSuggestionDiff,
+  onDoneReviewing,
+  initialTab = "comments",
+}: DocumentReviewRailProps) {
+  const [tab, setTab] = useState<"comments" | "suggestions">(initialTab);
+  const [filters, setFilters] = useState<Set<ReviewFilter>>(new Set(["open"]));
+  const [composeOverall, setComposeOverall] = useState(false);
+  const [overall, setOverall] = useState("");
+  const [overallPending, setOverallPending] = useState(false);
+
+  const counts = reviewIndex?.counts;
+  const commentCount = (counts?.openAnchoredThreads ?? 0) + (counts?.openReviewThreads ?? 0);
+  const suggestionCount = counts?.pendingSuggestions ?? 0;
+
+  const overallThreads = useMemo<RailThread[]>(
+    () =>
+      (reviewIndex?.reviewThreads ?? []).map((thread) => ({
+        id: thread.id,
+        kind: "overall" as const,
+        status: thread.status,
+        anchorState: null,
+        selectedText: null,
+        comments: thread.comments,
+      })),
+    [reviewIndex?.reviewThreads],
+  );
+
+  const anchoredThreads = useMemo<RailThread[]>(
+    () =>
+      (reviewIndex?.annotationThreads ?? []).map((thread) => ({
+        id: thread.id,
+        kind: "anchored" as const,
+        status: thread.status,
+        anchorState: thread.anchorState,
+        selectedText: thread.selectedText,
+        comments: thread.comments,
+      })),
+    [reviewIndex?.annotationThreads],
+  );
+
+  const activeFilters = filters.size === 0 ? new Set<ReviewFilter>(FILTERS.map((f) => f.id)) : filters;
+
+  const threadMatches = (thread: RailThread): boolean => {
+    if (thread.anchorState === "orphaned") return activeFilters.has("orphaned");
+    if (thread.anchorState === "stale") return activeFilters.has("stale");
+    if (thread.status === "resolved") return activeFilters.has("resolved");
+    return activeFilters.has("open");
+  };
+
+  const suggestionMatches = (suggestion: DocumentSuggestionWithComments): boolean => {
+    if (suggestion.anchorState === "orphaned") return activeFilters.has("orphaned");
+    if (suggestion.anchorState === "stale") return activeFilters.has("stale");
+    if (suggestion.status !== "pending") return activeFilters.has("resolved");
+    return activeFilters.has("open");
+  };
+
+  const visibleOverall = overallThreads.filter(threadMatches);
+  const visibleAnchored = anchoredThreads.filter(threadMatches);
+  const orphanedThreads = visibleAnchored.filter((t) => t.anchorState === "orphaned");
+  const nonOrphanThreads = visibleAnchored.filter((t) => t.anchorState !== "orphaned");
+
+  const suggestions = reviewIndex?.suggestions ?? [];
+  const visibleSuggestions = suggestions.filter(suggestionMatches);
+  const orphanedSuggestions = visibleSuggestions.filter((s) => s.anchorState === "orphaned");
+  const nonOrphanSuggestions = visibleSuggestions.filter((s) => s.anchorState !== "orphaned");
+
+  const toggleFilter = (id: ReviewFilter) => {
+    setFilters((prev) => {
+      const next = new Set(prev);
+      if (next.has(id)) next.delete(id);
+      else next.add(id);
+      return next;
+    });
+  };
+
+  const handleAddOverall = async () => {
+    const trimmed = overall.trim();
+    if (!trimmed || !onAddOverallComment) return;
+    setOverallPending(true);
+    try {
+      await onAddOverallComment(trimmed);
+      setOverall("");
+      setComposeOverall(false);
+    } finally {
+      setOverallPending(false);
+    }
+  };
+
+  return (
+    <TooltipProvider delayDuration={200}>
+      <div className="flex h-full min-h-0 flex-col">
+        <Tabs value={tab} onValueChange={(value) => setTab(value as typeof tab)} className="flex min-h-0 flex-1 flex-col">
+          <div className="border-b border-border px-2 pt-2">
+            <TabsList variant="line" className="w-full">
+              <TabsTrigger value="comments" className="flex-1" data-testid="rail-tab-comments">
+                Comments ({commentCount})
+              </TabsTrigger>
+              <TabsTrigger value="suggestions" className="flex-1" data-testid="rail-tab-suggestions">
+                Suggestions ({suggestionCount})
+              </TabsTrigger>
+            </TabsList>
+            <div className="flex flex-wrap items-center gap-1 py-2" role="group" aria-label="Review filters">
+              {FILTERS.map((filter) => (
+                <button
+                  key={filter.id}
+                  type="button"
+                  data-testid={`rail-filter-${filter.id}`}
+                  data-active={filters.has(filter.id) || undefined}
+                  onClick={() => toggleFilter(filter.id)}
+                  className={cn(
+                    "rounded-full border px-2 py-0.5 text-[11px] font-medium transition-colors",
+                    filters.has(filter.id)
+                      ? "border-primary bg-primary/10 text-foreground"
+                      : "border-border text-muted-foreground hover:bg-accent/50",
+                  )}
+                >
+                  {filter.label}
+                </button>
+              ))}
+            </div>
+          </div>
+
+          <div className="min-h-0 flex-1 overflow-y-auto p-2">
+            {loading ? (
+              <RailSkeleton />
+            ) : (
+              <>
+                <TabsContent value="comments" className="mt-0 space-y-2">
+                  {onAddOverallComment ? (
+                    composeOverall ? (
+                      <div className="space-y-2 rounded-md border border-border bg-card p-2">
+                        <Textarea
+                          data-testid="rail-overall-composer"
+                          value={overall}
+                          onChange={(event) => setOverall(event.currentTarget.value)}
+                          placeholder="Leave overall feedback on the whole document…"
+                          rows={3}
+                          className="resize-none text-sm"
+                        />
+                        <div className="flex items-center justify-end gap-1.5">
+                          <Button type="button" size="sm" variant="ghost" className="h-7 px-2 text-xs" onClick={() => setComposeOverall(false)}>
+                            Cancel
+                          </Button>
+                          <Button
+                            type="button"
+                            size="sm"
+                            className="h-7 px-2 text-xs"
+                            disabled={!overall.trim() || overallPending}
+                            onClick={handleAddOverall}
+                          >
+                            Comment
+                          </Button>
+                        </div>
+                      </div>
+                    ) : (
+                      <Button
+                        type="button"
+                        size="sm"
+                        variant="outline"
+                        className="h-8 w-full justify-start gap-1.5 text-xs"
+                        onClick={() => setComposeOverall(true)}
+                        data-testid="rail-add-overall"
+                      >
+                        <MessageSquarePlus className="h-3.5 w-3.5" aria-hidden="true" />
+                        Add overall comment
+                      </Button>
+                    )
+                  ) : null}
+
+                  {visibleOverall.map((thread) => (
+                    <DocumentThreadCard
+                      key={thread.id}
+                      thread={thread}
+                      canReview={canReview}
+                      authorMaps={authorMaps}
+                      focused={focusedThreadId === thread.id}
+                      onFocus={onFocusThread}
+                      onReply={onReplyThread}
+                      onToggleResolved={onToggleThreadResolved}
+                    />
+                  ))}
+
+                  {orphanedThreads.length > 0 ? (
+                    <OrphanGroup count={orphanedThreads.length}>
+                      {orphanedThreads.map((thread) => (
+                        <DocumentThreadCard
+                          key={thread.id}
+                          thread={thread}
+                          canReview={canReview}
+                          authorMaps={authorMaps}
+                          focused={focusedThreadId === thread.id}
+                          onFocus={onFocusThread}
+                          onReply={onReplyThread}
+                          onToggleResolved={onToggleThreadResolved}
+                        />
+                      ))}
+                    </OrphanGroup>
+                  ) : null}
+
+                  {nonOrphanThreads.map((thread) => (
+                    <DocumentThreadCard
+                      key={thread.id}
+                      thread={thread}
+                      canReview={canReview}
+                      authorMaps={authorMaps}
+                      focused={focusedThreadId === thread.id}
+                      onFocus={onFocusThread}
+                      onReply={onReplyThread}
+                      onToggleResolved={onToggleThreadResolved}
+                    />
+                  ))}
+
+                  {visibleOverall.length === 0 && visibleAnchored.length === 0 ? (
+                    <RailEmpty message="No feedback yet. Highlight text to comment or suggest an edit." />
+                  ) : null}
+                </TabsContent>
+
+                <TabsContent value="suggestions" className="mt-0 space-y-2">
+                  {orphanedSuggestions.length > 0 ? (
+                    <OrphanGroup count={orphanedSuggestions.length}>
+                      {orphanedSuggestions.map((suggestion) => (
+                        <SuggestionCard
+                          key={suggestion.id}
+                          suggestion={suggestion}
+                          latestRevisionId={latestRevisionId}
+                          canReview={canReview}
+                          authorMaps={authorMaps}
+                          onAccept={onAcceptSuggestion}
+                          onReject={onRejectSuggestion}
+                          onReply={onReplySuggestion}
+                          onViewDiff={onViewSuggestionDiff}
+                        />
+                      ))}
+                    </OrphanGroup>
+                  ) : null}
+
+                  {nonOrphanSuggestions.map((suggestion) => (
+                    <SuggestionCard
+                      key={suggestion.id}
+                      suggestion={suggestion}
+                      latestRevisionId={latestRevisionId}
+                      canReview={canReview}
+                      authorMaps={authorMaps}
+                      onAccept={onAcceptSuggestion}
+                      onReject={onRejectSuggestion}
+                      onReply={onReplySuggestion}
+                      onViewDiff={onViewSuggestionDiff}
+                    />
+                  ))}
+
+                  {visibleSuggestions.length === 0 ? (
+                    <RailEmpty message="No suggested edits. Select text and choose “Suggest edit”." />
+                  ) : null}
+                </TabsContent>
+              </>
+            )}
+          </div>
+        </Tabs>
+
+        <div className="border-t border-border p-2">
+          <Tooltip>
+            <TooltipTrigger asChild>
+              <span className="block">
+                <Button
+                  type="button"
+                  className="w-full"
+                  size="sm"
+                  disabled={!canFinishReview}
+                  onClick={onDoneReviewing}
+                  data-testid="rail-done-reviewing"
+                >
+                  <CheckCircle2 className="mr-1.5 h-4 w-4" aria-hidden="true" />
+                  Done reviewing
+                </Button>
+              </span>
+            </TooltipTrigger>
+            {!canFinishReview ? (
+              <TooltipContent>
+                {doneReviewingDisabledReason ?? "Read-only documents can't be marked reviewed"}
+              </TooltipContent>
+            ) : null}
+          </Tooltip>
+        </div>
+      </div>
+    </TooltipProvider>
+  );
+}
+
+function OrphanGroup({ count, children }: { count: number; children: React.ReactNode }) {
+  const [open, setOpen] = useState(true);
+  return (
+    <div className="rounded-md border border-dashed border-border bg-muted/30 p-1.5" data-testid="rail-orphan-group">
+      <button
+        type="button"
+        className="flex w-full items-center justify-between px-1 py-0.5 text-[11px] font-medium text-muted-foreground"
+        onClick={() => setOpen((value) => !value)}
+        aria-expanded={open}
+      >
+        <span>Orphaned feedback ({count})</span>
+        <span aria-hidden="true">{open ? "−" : "+"}</span>
+      </button>
+      {open ? <div className="mt-1.5 space-y-2">{children}</div> : null}
+    </div>
+  );
+}
+
+function RailEmpty({ message }: { message: string }) {
+  return (
+    <div className="px-2 py-8 text-center text-xs text-muted-foreground" data-testid="rail-empty">
+      <p>{message}</p>
+      <p className="mt-1 text-[11px] opacity-70">⌘⇧M to comment from a selection</p>
+    </div>
+  );
+}
+
+function RailSkeleton() {
+  return (
+    <div className="space-y-2" data-testid="rail-skeleton">
+      {[0, 1, 2].map((index) => (
+        <div key={index} className="h-20 animate-pulse rounded-md border border-border bg-muted/40" />
+      ))}
+    </div>
+  );
+}
diff --git a/ui/src/components/documents/DocumentThreadCard.tsx b/ui/src/components/documents/DocumentThreadCard.tsx
new file mode 100644
index 00000000000..f6bb1dfc373
--- /dev/null
+++ b/ui/src/components/documents/DocumentThreadCard.tsx
@@ -0,0 +1,203 @@
+import { useState } from "react";
+import { AlertTriangle, Unlink } from "lucide-react";
+import { Badge } from "@/components/ui/badge";
+import { Button } from "@/components/ui/button";
+import { Textarea } from "@/components/ui/textarea";
+import { MarkdownBody } from "@/components/MarkdownBody";
+import { cn, relativeTime } from "@/lib/utils";
+import {
+  resolveReviewAuthor,
+  type ReviewAuthorMaps,
+  type ReviewAuthorRef,
+} from "@/lib/document-review-authors";
+
+export type RailThreadKind = "anchored" | "overall";
+export type RailAnchorState = "active" | "stale" | "orphaned" | null;
+
+export interface RailComment extends ReviewAuthorRef {
+  id: string;
+  body: string;
+  createdAt: Date | string;
+}
+
+export interface RailThread {
+  id: string;
+  kind: RailThreadKind;
+  status: "open" | "resolved";
+  anchorState: RailAnchorState;
+  selectedText: string | null;
+  comments: RailComment[];
+}
+
+function stateBadge(thread: RailThread): { label: string; className: string; icon?: typeof AlertTriangle } {
+  if (thread.kind === "overall") {
+    return {
+      label: "Overall feedback",
+      className: "border-transparent bg-violet-100 text-violet-700 dark:bg-violet-900/50 dark:text-violet-300",
+    };
+  }
+  if (thread.anchorState === "orphaned") {
+    return {
+      label: "Orphaned",
+      className: "border-transparent bg-muted text-muted-foreground",
+      icon: Unlink,
+    };
+  }
+  if (thread.anchorState === "stale") {
+    return {
+      label: "Stale",
+      className: "border-transparent bg-amber-100 text-amber-700 dark:bg-amber-900/50 dark:text-amber-300",
+      icon: AlertTriangle,
+    };
+  }
+  if (thread.status === "resolved") {
+    return {
+      label: "Resolved",
+      className: "border-transparent bg-green-100 text-green-700 dark:bg-green-900/50 dark:text-green-300",
+    };
+  }
+  return {
+    label: "Open",
+    className: "border-transparent bg-yellow-100 text-yellow-800 dark:bg-yellow-900/50 dark:text-yellow-300",
+  };
+}
+
+export interface DocumentThreadCardProps {
+  thread: RailThread;
+  focused?: boolean;
+  canReview: boolean;
+  authorMaps?: ReviewAuthorMaps;
+  onFocus?: (threadId: string) => void;
+  onReply: (thread: RailThread, body: string) => Promise<void> | void;
+  onToggleResolved: (thread: RailThread, resolved: boolean) => Promise<void> | void;
+}
+
+/**
+ * Review-rail card for an anchored comment thread, a document-level overall
+ * comment, stale/orphaned anchors. Renders the status badge, anchored snippet,
+ * the comment thread, a reply composer, and a Resolve/Reopen toggle.
+ */
+export function DocumentThreadCard({
+  thread,
+  focused,
+  canReview,
+  authorMaps,
+  onFocus,
+  onReply,
+  onToggleResolved,
+}: DocumentThreadCardProps) {
+  const [reply, setReply] = useState("");
+  const [pending, setPending] = useState<null | "reply" | "resolve">(null);
+  const badge = stateBadge(thread);
+  const BadgeIcon = badge.icon;
+
+  const handleReply = async () => {
+    const trimmed = reply.trim();
+    if (!trimmed) return;
+    setPending("reply");
+    try {
+      await onReply(thread, trimmed);
+      setReply("");
+    } finally {
+      setPending(null);
+    }
+  };
+
+  const handleToggle = async () => {
+    setPending("resolve");
+    try {
+      await onToggleResolved(thread, thread.status !== "resolved");
+    } finally {
+      setPending(null);
+    }
+  };
+
+  return (
+    <article
+      role="article"
+      data-testid={`thread-card-${thread.id}`}
+      data-status={thread.status}
+      data-anchor-state={thread.anchorState ?? undefined}
+      data-focused={focused || undefined}
+      className={cn(
+        "rounded-md border border-border bg-card p-2.5 text-card-foreground shadow-sm",
+        focused && "border-l-2 border-l-primary",
+      )}
+      onClick={() => onFocus?.(thread.id)}
+    >
+      <header className="mb-1.5 flex items-center justify-between gap-2">
+        <Badge className={cn("gap-1 px-1.5 py-0 text-[10px] font-medium", badge.className)}>
+          {BadgeIcon ? <BadgeIcon className="h-3 w-3" aria-hidden="true" /> : null}
+          {badge.label}
+        </Badge>
+      </header>
+
+      {thread.kind === "anchored" && thread.selectedText ? (
+        <p
+          id={`thread-quote-${thread.id}`}
+          className={cn(
+            "mb-2 border-l-2 border-border pl-2 text-[11px] italic text-muted-foreground",
+            thread.anchorState === "stale" && "border-amber-400",
+            thread.anchorState === "orphaned" && "border-dashed",
+          )}
+        >
+          “{thread.selectedText}”
+        </p>
+      ) : null}
+
+      <div className="space-y-1.5">
+        {thread.comments.map((comment) => {
+          const author = resolveReviewAuthor(comment, authorMaps ?? {});
+          return (
+            <div key={comment.id} className="rounded border border-border bg-background px-2 py-1">
+              <div className="mb-0.5 flex items-center justify-between gap-2 text-[11px]">
+                <span className="min-w-0 truncate">
+                  <span className="font-medium text-foreground">{author.name}</span>
+                  {author.role === "agent" ? <span className="ml-1 text-muted-foreground">· agent</span> : null}
+                </span>
+                <span className="text-muted-foreground">{relativeTime(comment.createdAt)}</span>
+              </div>
+              <MarkdownBody className="text-sm leading-6">{comment.body}</MarkdownBody>
+            </div>
+          );
+        })}
+      </div>
+
+      {canReview ? (
+        <div className="mt-2 space-y-2">
+          <Textarea
+            data-testid={`thread-reply-${thread.id}`}
+            value={reply}
+            onChange={(event) => setReply(event.currentTarget.value)}
+            placeholder="Reply…"
+            rows={2}
+            className="min-h-[2.25rem] resize-none text-sm"
+          />
+          <div className="flex items-center justify-between gap-2">
+            <Button
+              type="button"
+              size="sm"
+              variant="ghost"
+              className="h-7 px-2 text-xs"
+              disabled={!reply.trim() || pending != null}
+              onClick={handleReply}
+            >
+              Reply
+            </Button>
+            <Button
+              type="button"
+              size="sm"
+              variant="outline"
+              className="h-7 px-2 text-xs"
+              disabled={pending != null}
+              onClick={handleToggle}
+              data-testid={`thread-resolve-${thread.id}`}
+            >
+              {thread.status === "resolved" ? "Reopen" : "Resolve"}
+            </Button>
+          </div>
+        </div>
+      ) : null}
+    </article>
+  );
+}
diff --git a/ui/src/components/documents/SelectionToolbar.test.tsx b/ui/src/components/documents/SelectionToolbar.test.tsx
new file mode 100644
index 00000000000..b03ea7e6e58
--- /dev/null
+++ b/ui/src/components/documents/SelectionToolbar.test.tsx
@@ -0,0 +1,67 @@
+// @vitest-environment jsdom
+
+import { flushSync } from "react-dom";
+import { createRoot, type Root } from "react-dom/client";
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+import { SelectionToolbar } from "./SelectionToolbar";
+
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+(globalThis as any).IS_REACT_ACT_ENVIRONMENT = true;
+
+async function act(callback: () => void | Promise<void>) {
+  let result: void | Promise<void> = undefined;
+  flushSync(() => {
+    result = callback();
+  });
+  await result;
+}
+
+let container: HTMLDivElement;
+let root: Root;
+
+beforeEach(() => {
+  container = document.createElement("div");
+  document.body.appendChild(container);
+  root = createRoot(container);
+});
+
+afterEach(() => {
+  act(() => root.unmount());
+  container.remove();
+});
+
+describe("SelectionToolbar", () => {
+  it("invokes onComment when Comment is clicked", async () => {
+    const onComment = vi.fn();
+    await act(() =>
+      root.render(<SelectionToolbar onComment={onComment} onSuggest={vi.fn()} onCopyLink={vi.fn()} />),
+    );
+    await act(() => container.querySelector<HTMLButtonElement>('[data-testid="selection-toolbar-comment"]')!.click());
+    expect(onComment).toHaveBeenCalledTimes(1);
+  });
+
+  it("renders the Suggest edit trigger and copy-link button", async () => {
+    await act(() =>
+      root.render(<SelectionToolbar onComment={vi.fn()} onSuggest={vi.fn()} onCopyLink={vi.fn()} />),
+    );
+    expect(container.querySelector('[data-testid="selection-toolbar-suggest"]')).not.toBeNull();
+    expect(container.querySelector('[data-testid="selection-toolbar-copy"]')).not.toBeNull();
+  });
+
+  it("disables actions when comment/suggest are disabled", async () => {
+    await act(() =>
+      root.render(
+        <SelectionToolbar
+          onComment={vi.fn()}
+          onSuggest={vi.fn()}
+          commentDisabled
+          suggestDisabled
+        />,
+      ),
+    );
+    expect(container.querySelector<HTMLButtonElement>('[data-testid="selection-toolbar-comment"]')!.disabled).toBe(true);
+    expect(container.querySelector<HTMLButtonElement>('[data-testid="selection-toolbar-suggest"]')!.disabled).toBe(true);
+    // No copy-link handler → button omitted.
+    expect(container.querySelector('[data-testid="selection-toolbar-copy"]')).toBeNull();
+  });
+});
diff --git a/ui/src/components/documents/SelectionToolbar.tsx b/ui/src/components/documents/SelectionToolbar.tsx
new file mode 100644
index 00000000000..5dbe2771f03
--- /dev/null
+++ b/ui/src/components/documents/SelectionToolbar.tsx
@@ -0,0 +1,124 @@
+import type { DocumentSuggestionKind, DocumentSuggestionInsertPosition } from "@paperclipai/shared";
+import { Link2, MessageSquarePlus, Pencil } from "lucide-react";
+import { Button } from "@/components/ui/button";
+import {
+  DropdownMenu,
+  DropdownMenuContent,
+  DropdownMenuItem,
+  DropdownMenuTrigger,
+} from "@/components/ui/dropdown-menu";
+import { cn } from "@/lib/utils";
+
+export interface SuggestionDraftIntent {
+  kind: DocumentSuggestionKind;
+  insertionPosition?: DocumentSuggestionInsertPosition;
+}
+
+const SUGGEST_OPTIONS: { label: string; intent: SuggestionDraftIntent }[] = [
+  { label: "Replace selection…", intent: { kind: "substitution" } },
+  { label: "Delete selection", intent: { kind: "deletion" } },
+  { label: "Insert before…", intent: { kind: "insertion", insertionPosition: "before" } },
+  { label: "Insert after…", intent: { kind: "insertion", insertionPosition: "after" } },
+];
+
+export interface SelectionToolbarProps {
+  /** Add an anchored comment on the current selection. */
+  onComment: () => void;
+  /** Start a suggested-edit draft of a given kind on the current selection. */
+  onSuggest: (intent: SuggestionDraftIntent) => void;
+  /** Copy a deep link to the current selection. Omitted hides the button. */
+  onCopyLink?: () => void;
+  commentDisabled?: boolean;
+  commentDisabledReason?: string | null;
+  suggestDisabled?: boolean;
+  suggestDisabledReason?: string | null;
+  className?: string;
+}
+
+/**
+ * NEW floating selection toolbar shown when the reader selects body text. Offers
+ * "Comment" and a "Suggest edit ▾" menu (Replace / Delete / Insert before /
+ * Insert after — the four Roughdraft primitives) plus an optional copy-link. The
+ * caret-anchored positioning is owned by the body annotation layer; this is the
+ * presentational action cluster injected into it (and reused standalone in
+ * Storybook/tests).
+ */
+export function SelectionToolbar({
+  onComment,
+  onSuggest,
+  onCopyLink,
+  commentDisabled,
+  commentDisabledReason,
+  suggestDisabled,
+  suggestDisabledReason,
+  className,
+}: SelectionToolbarProps) {
+  return (
+    <div
+      data-testid="document-selection-toolbar"
+      role="toolbar"
+      aria-label="Selection actions"
+      className={cn("flex items-center gap-0.5", className)}
+      onMouseDown={(event) => event.preventDefault()}
+    >
+      <Button
+        type="button"
+        size="sm"
+        variant="ghost"
+        className="h-7 gap-1 px-2 text-xs"
+        onClick={onComment}
+        disabled={commentDisabled}
+        title={commentDisabled ? commentDisabledReason ?? undefined : "Add comment on selection (⌘⇧M)"}
+        data-testid="selection-toolbar-comment"
+      >
+        <MessageSquarePlus className="h-3.5 w-3.5" aria-hidden="true" />
+        Comment
+      </Button>
+
+      <DropdownMenu>
+        <DropdownMenuTrigger asChild>
+          <Button
+            type="button"
+            size="sm"
+            variant="ghost"
+            className="h-7 gap-1 px-2 text-xs"
+            disabled={suggestDisabled}
+            title={suggestDisabled ? suggestDisabledReason ?? undefined : "Suggest an edit on selection"}
+            data-testid="selection-toolbar-suggest"
+          >
+            <Pencil className="h-3.5 w-3.5" aria-hidden="true" />
+            Suggest edit
+          </Button>
+        </DropdownMenuTrigger>
+        <DropdownMenuContent align="start" className="w-44">
+          {SUGGEST_OPTIONS.map((option) => (
+            <DropdownMenuItem
+              key={option.label}
+              onSelect={() => onSuggest(option.intent)}
+              data-testid={`selection-toolbar-suggest-${option.intent.kind}${
+                option.intent.insertionPosition ? `-${option.intent.insertionPosition}` : ""
+              }`}
+            >
+              {option.label}
+            </DropdownMenuItem>
+          ))}
+        </DropdownMenuContent>
+      </DropdownMenu>
+
+      {onCopyLink ? (
+        <Button
+          type="button"
+          size="icon-xs"
+          variant="ghost"
+          className="h-7 w-7"
+          onClick={onCopyLink}
+          aria-label="Copy link to selection"
+          title="Copy link to selection"
+          data-testid="selection-toolbar-copy"
+        >
+          <Link2 className="h-3.5 w-3.5" aria-hidden="true" />
+        </Button>
+      ) : null}
+    </div>
+  );
+}
diff --git a/ui/src/components/documents/SuggestionCard.test.tsx b/ui/src/components/documents/SuggestionCard.test.tsx
new file mode 100644
index 00000000000..7292fd9e0a7
--- /dev/null
+++ b/ui/src/components/documents/SuggestionCard.test.tsx
@@ -0,0 +1,180 @@
+// @vitest-environment jsdom
+
+import { flushSync } from "react-dom";
+import { createRoot, type Root } from "react-dom/client";
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+import type { DocumentSuggestionWithComments } from "@paperclipai/shared";
+import { SuggestionCard } from "./SuggestionCard";
+
+vi.mock("@/components/MarkdownBody", () => ({
+  MarkdownBody: ({ children }: { children: string }) => <p>{children}</p>,
+}));
+
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+(globalThis as any).IS_REACT_ACT_ENVIRONMENT = true;
+
+async function act(callback: () => void | Promise<void>) {
+  let result: void | Promise<void> = undefined;
+  flushSync(() => {
+    result = callback();
+  });
+  await result;
+}
+
+let container: HTMLDivElement;
+let root: Root;
+
+beforeEach(() => {
+  container = document.createElement("div");
+  document.body.appendChild(container);
+  root = createRoot(container);
+});
+
+afterEach(() => {
+  act(() => root.unmount());
+  container.remove();
+});
+
+function makeSuggestion(overrides: Partial<DocumentSuggestionWithComments> = {}): DocumentSuggestionWithComments {
+  return {
+    id: "sug-1",
+    companyId: "c1",
+    issueId: "i1",
+    documentId: "d1",
+    documentKey: "spec",
+    kind: "substitution",
+    status: "pending",
+    anchorState: "active",
+    anchorConfidence: "exact",
+    originalRevisionId: "rev-1",
+    originalRevisionNumber: 12,
+    currentRevisionId: "rev-1",
+    currentRevisionNumber: 12,
+    selectedText: "old text",
+    proposedText: "new text",
+    insertionPosition: null,
+    prefixText: "",
+    suffixText: "",
+    normalizedStart: 0,
+    normalizedEnd: 8,
+    markdownStart: 0,
+    markdownEnd: 8,
+    anchorSelector: { quote: { exact: "old text", prefix: "", suffix: "" }, position: { normalizedStart: 0, normalizedEnd: 8, markdownStart: 0, markdownEnd: 8 } },
+    createdByAgentId: "agent-1",
+    createdByUserId: null,
+    acceptedByAgentId: null,
+    acceptedByUserId: null,
+    acceptedAt: null,
+    acceptedRevisionId: null,
+    rejectedByAgentId: null,
+    rejectedByUserId: null,
+    rejectedAt: null,
+    createdAt: new Date("2026-06-01T00:00:00Z"),
+    updatedAt: new Date("2026-06-01T00:00:00Z"),
+    comments: [],
+    ...overrides,
+  };
+}
+
+describe("SuggestionCard", () => {
+  it("renders the kind label and source/proposed diff", async () => {
+    await act(() =>
+      root.render(
+        <SuggestionCard
+          suggestion={makeSuggestion()}
+          latestRevisionId="rev-1"
+          canReview
+          onAccept={vi.fn()}
+          onReject={vi.fn()}
+          onReply={vi.fn()}
+        />,
+      ),
+    );
+    expect(container.textContent).toContain("Replace");
+    expect(container.textContent).toContain("old text");
+    expect(container.textContent).toContain("new text");
+  });
+
+  it("accepts a pending suggestion via the Accept button", async () => {
+    const onAccept = vi.fn();
+    await act(() =>
+      root.render(
+        <SuggestionCard
+          suggestion={makeSuggestion()}
+          latestRevisionId="rev-1"
+          canReview
+          onAccept={onAccept}
+          onReject={vi.fn()}
+          onReply={vi.fn()}
+        />,
+      ),
+    );
+    const accept = container.querySelector<HTMLButtonElement>('[data-testid="suggestion-accept-sug-1"]');
+    expect(accept).not.toBeNull();
+    expect(accept?.disabled).toBe(false);
+    await act(() => accept!.click());
+    expect(onAccept).toHaveBeenCalledTimes(1);
+  });
+
+  it("gates Accept behind Needs rebase when the anchor revision lags the document", async () => {
+    await act(() =>
+      root.render(
+        <SuggestionCard
+          suggestion={makeSuggestion({ currentRevisionId: "rev-1" })}
+          latestRevisionId="rev-2"
+          canReview
+          onAccept={vi.fn()}
+          onReject={vi.fn()}
+          onReply={vi.fn()}
+        />,
+      ),
+    );
+    expect(container.querySelector('[data-testid="suggestion-needs-rebase-sug-1"]')).not.toBeNull();
+    const accept = container.querySelector<HTMLButtonElement>('[data-testid="suggestion-accept-sug-1"]');
+    expect(accept?.disabled).toBe(true);
+  });
+
+  it("requires a reason to reject", async () => {
+    const onReject = vi.fn();
+    await act(() =>
+      root.render(
+        <SuggestionCard
+          suggestion={makeSuggestion()}
+          latestRevisionId="rev-1"
+          canReview
+          onAccept={vi.fn()}
+          onReject={onReject}
+          onReply={vi.fn()}
+        />,
+      ),
+    );
+    await act(() => container.querySelector<HTMLButtonElement>('[data-testid="suggestion-reject-toggle-sug-1"]')!.click());
+    const confirm = container.querySelector<HTMLButtonElement>('[data-testid="suggestion-reject-confirm-sug-1"]');
+    expect(confirm?.disabled).toBe(true); // no reason yet
+    const reason = container.querySelector<HTMLTextAreaElement>('[data-testid="suggestion-reject-reason-sug-1"]')!;
+    const setter = Object.getOwnPropertyDescriptor(window.HTMLTextAreaElement.prototype, "value")!.set!;
+    await act(() => {
+      setter.call(reason, "Not needed");
+      reason.dispatchEvent(new Event("input", { bubbles: true }));
+    });
+    await act(() => container.querySelector<HTMLButtonElement>('[data-testid="suggestion-reject-confirm-sug-1"]')!.click());
+    expect(onReject).toHaveBeenCalledWith(expect.objectContaining({ id: "sug-1" }), "Not needed");
+  });
+
+  it("hides review actions for read-only viewers", async () => {
+    await act(() =>
+      root.render(
+        <SuggestionCard
+          suggestion={makeSuggestion()}
+          latestRevisionId="rev-1"
+          canReview={false}
+          onAccept={vi.fn()}
+          onReject={vi.fn()}
+          onReply={vi.fn()}
+        />,
+      ),
+    );
+    expect(container.querySelector('[data-testid="suggestion-accept-sug-1"]')).toBeNull();
+    expect(container.querySelector('[data-testid="suggestion-reply-sug-1"]')).toBeNull();
+  });
+});
diff --git a/ui/src/components/documents/SuggestionCard.tsx b/ui/src/components/documents/SuggestionCard.tsx
new file mode 100644
index 00000000000..97ebf2094ba
--- /dev/null
+++ b/ui/src/components/documents/SuggestionCard.tsx
@@ -0,0 +1,391 @@
+import { useState } from "react";
+import type {
+  DocumentSuggestionKind,
+  DocumentSuggestionWithComments,
+} from "@paperclipai/shared";
+import { AlertTriangle, Check, MoreHorizontal, X } from "lucide-react";
+import { Button } from "@/components/ui/button";
+import { Badge } from "@/components/ui/badge";
+import { Textarea } from "@/components/ui/textarea";
+import {
+  Tooltip,
+  TooltipContent,
+  TooltipProvider,
+  TooltipTrigger,
+} from "@/components/ui/tooltip";
+import { MarkdownBody } from "@/components/MarkdownBody";
+import { cn, relativeTime } from "@/lib/utils";
+import {
+  resolveReviewAuthor,
+  type ReviewAuthorMaps,
+} from "@/lib/document-review-authors";
+
+const KIND_LABEL: Record<DocumentSuggestionKind, string> = {
+  insertion: "Insert",
+  deletion: "Delete",
+  substitution: "Replace",
+};
+
+const KIND_BADGE_CLASS: Record<DocumentSuggestionKind, string> = {
+  insertion: "border-transparent bg-emerald-100 text-emerald-700 dark:bg-emerald-900/50 dark:text-emerald-300",
+  deletion: "border-transparent bg-rose-100 text-rose-700 dark:bg-rose-900/50 dark:text-rose-300",
+  substitution: "border-transparent bg-amber-100 text-amber-700 dark:bg-amber-900/50 dark:text-amber-300",
+};
+
+export interface SuggestionCardProps {
+  suggestion: DocumentSuggestionWithComments;
+  /** Latest revision of the document; drives the "Needs rebase" gate. */
+  latestRevisionId: string | null;
+  /** Whether the viewer can accept/reject (board reviewer with edit rights). */
+  canReview: boolean;
+  authorMaps?: ReviewAuthorMaps;
+  onAccept: (suggestion: DocumentSuggestionWithComments) => Promise<void> | void;
+  onReject: (suggestion: DocumentSuggestionWithComments, reason: string) => Promise<void> | void;
+  onReply: (suggestion: DocumentSuggestionWithComments, body: string) => Promise<void> | void;
+  /** Opens the diff modal for the revision this suggestion would produce. */
+  onViewDiff?: (suggestion: DocumentSuggestionWithComments) => void;
+  className?: string;
+}
+
+/**
+ * NEW review-rail card for a suggested edit (insert / delete / replace).
+ * Composes Badge + author chip + an inline CriticMarkup-style source/proposed
+ * diff, a discussion thread, a reply composer, and Accept/Reject actions.
+ *
+ * Accept disables on a stale `baseRevisionId` (the suggestion was anchored to an
+ * older revision) or a drifted/lost anchor — surfaced as a "Needs rebase" badge.
+ */
+export function SuggestionCard({
+  suggestion,
+  latestRevisionId,
+  canReview,
+  authorMaps,
+  onAccept,
+  onReject,
+  onReply,
+  onViewDiff,
+  className,
+}: SuggestionCardProps) {
+  const [reply, setReply] = useState("");
+  const [rejecting, setRejecting] = useState(false);
+  const [reason, setReason] = useState("");
+  const [pending, setPending] = useState<null | "accept" | "reject" | "reply">(null);
+
+  const author = resolveReviewAuthor(suggestion, authorMaps ?? {});
+  const kindLabel = KIND_LABEL[suggestion.kind];
+  const isPending = suggestion.status === "pending";
+
+  // Needs rebase when the suggestion's anchor revision lags the document, or the
+  // anchor drifted/was lost during a remap. Accepting then would apply against a
+  // mismatched base, so the backend rejects it — gate the button instead.
+  const anchorDrifted = suggestion.anchorState !== "active";
+  const revisionDrifted =
+    latestRevisionId != null && suggestion.currentRevisionId != null
+      ? suggestion.currentRevisionId !== latestRevisionId
+      : false;
+  const needsRebase = isPending && (anchorDrifted || revisionDrifted);
+  const acceptDisabled = pending != null || needsRebase;
+
+  const handleAccept = async () => {
+    setPending("accept");
+    try {
+      await onAccept(suggestion);
+    } finally {
+      setPending(null);
+    }
+  };
+
+  const handleReject = async () => {
+    const trimmed = reason.trim();
+    if (!trimmed) return;
+    setPending("reject");
+    try {
+      await onReject(suggestion, trimmed);
+      setRejecting(false);
+      setReason("");
+    } finally {
+      setPending(null);
+    }
+  };
+
+  const handleReply = async () => {
+    const trimmed = reply.trim();
+    if (!trimmed) return;
+    setPending("reply");
+    try {
+      await onReply(suggestion, trimmed);
+      setReply("");
+    } finally {
+      setPending(null);
+    }
+  };
+
+  return (
+    <TooltipProvider delayDuration={200}>
+      <article
+        data-testid={`suggestion-card-${suggestion.id}`}
+        data-kind={suggestion.kind}
+        data-status={suggestion.status}
+        className={cn(
+          "rounded-md border border-border bg-card p-2.5 text-card-foreground shadow-sm",
+          suggestion.status === "rejected" && "opacity-70",
+          className,
+        )}
+      >
+        <header className="mb-1.5 flex items-center justify-between gap-2">
+          <div className="flex items-center gap-1.5">
+            <Badge className={cn("px-1.5 py-0 text-[10px] font-semibold uppercase", KIND_BADGE_CLASS[suggestion.kind])}>
+              {kindLabel}
+            </Badge>
+            {needsRebase ? (
+              <Tooltip>
+                <TooltipTrigger asChild>
+                  <Badge
+                    data-testid={`suggestion-needs-rebase-${suggestion.id}`}
+                    className="gap-1 border-transparent bg-amber-100 px-1.5 py-0 text-[10px] font-medium text-amber-700 dark:bg-amber-900/50 dark:text-amber-300"
+                  >
+                    <AlertTriangle className="h-3 w-3" aria-hidden="true" />
+                    Needs rebase
+                  </Badge>
+                </TooltipTrigger>
+                <TooltipContent>
+                  Document changed since this was suggested. Reload and review again, or rebase the
+                  suggestion onto the latest revision.
+                </TooltipContent>
+              </Tooltip>
+            ) : null}
+            {suggestion.status === "accepted" ? (
+              <Badge className="border-transparent bg-green-100 px-1.5 py-0 text-[10px] text-green-700 dark:bg-green-900/50 dark:text-green-300">
+                Accepted
+              </Badge>
+            ) : null}
+            {suggestion.status === "rejected" ? (
+              <Badge className="border-transparent bg-muted px-1.5 py-0 text-[10px] text-muted-foreground">
+                Rejected
+              </Badge>
+            ) : null}
+          </div>
+          {onViewDiff ? (
+            <Button
+              type="button"
+              size="icon-xs"
+              variant="ghost"
+              aria-label="View suggestion diff"
+              title="View diff"
+              onClick={() => onViewDiff(suggestion)}
+            >
+              <MoreHorizontal className="h-4 w-4" aria-hidden="true" />
+            </Button>
+          ) : null}
+        </header>
+
+        <p className="mb-2 text-[11px] text-muted-foreground">
+          Suggested by <span className="font-medium text-foreground">{author.name}</span>
+          {author.role === "agent" ? " · agent" : null} · {relativeTime(suggestion.createdAt)}
+          {suggestion.originalRevisionNumber ? ` · rev ${suggestion.originalRevisionNumber}` : null}
+        </p>
+
+        <SuggestionDiff suggestion={suggestion} />
+
+        {suggestion.status === "rejected" && rejectionReason(suggestion) ? (
+          <p className="mt-2 rounded bg-muted/60 px-2 py-1 text-[11px] text-muted-foreground">
+            Rejected: {rejectionReason(suggestion)}
+          </p>
+        ) : null}
+
+        {suggestion.comments.length > 0 ? (
+          <div className="mt-2 space-y-1.5">
+            <p className="text-[11px] font-medium text-muted-foreground">
+              Discussion ({suggestion.comments.length})
+            </p>
+            {suggestion.comments.map((comment) => {
+              const commentAuthor = resolveReviewAuthor(comment, authorMaps ?? {});
+              return (
+                <div key={comment.id} className="rounded border border-border bg-background px-2 py-1">
+                  <div className="mb-0.5 flex items-center justify-between gap-2 text-[11px]">
+                    <span className="font-medium text-foreground">{commentAuthor.name}</span>
+                    <span className="text-muted-foreground">{relativeTime(comment.createdAt)}</span>
+                  </div>
+                  <MarkdownBody className="text-sm leading-6">{comment.body}</MarkdownBody>
+                </div>
+              );
+            })}
+          </div>
+        ) : null}
+
+        {canReview ? (
+          <div className="mt-2 space-y-2">
+            <Textarea
+              data-testid={`suggestion-reply-${suggestion.id}`}
+              value={reply}
+              onChange={(event) => setReply(event.currentTarget.value)}
+              placeholder="Reply…"
+              rows={2}
+              className="min-h-[2.25rem] resize-none text-sm"
+            />
+            <div className="flex flex-wrap items-center justify-between gap-2">
+              <Button
+                type="button"
+                size="sm"
+                variant="ghost"
+                className="h-7 px-2 text-xs"
+                disabled={!reply.trim() || pending != null}
+                onClick={handleReply}
+              >
+                Reply
+              </Button>
+              {isPending ? (
+                <div className="flex items-center gap-1.5">
+                  {rejecting ? null : (
+                    <Tooltip>
+                      <TooltipTrigger asChild>
+                        <span>
+                          <Button
+                            type="button"
+                            size="sm"
+                            variant="outline"
+                            className="h-7 gap-1 px-2 text-xs"
+                            disabled={acceptDisabled}
+                            onClick={handleAccept}
+                            data-testid={`suggestion-accept-${suggestion.id}`}
+                          >
+                            <Check className="h-3.5 w-3.5" aria-hidden="true" />
+                            Accept
+                          </Button>
+                        </span>
+                      </TooltipTrigger>
+                      {needsRebase ? (
+                        <TooltipContent>
+                          Document changed since this was suggested. Reload and review again, or
+                          rebase the suggestion onto the latest revision.
+                        </TooltipContent>
+                      ) : null}
+                    </Tooltip>
+                  )}
+                  <Button
+                    type="button"
+                    size="sm"
+                    variant="ghost"
+                    className="h-7 gap-1 px-2 text-xs text-destructive hover:text-destructive"
+                    onClick={() => setRejecting((value) => !value)}
+                    data-testid={`suggestion-reject-toggle-${suggestion.id}`}
+                  >
+                    <X className="h-3.5 w-3.5" aria-hidden="true" />
+                    Reject
+                  </Button>
+                </div>
+              ) : null}
+            </div>
+            {rejecting ? (
+              <div className="space-y-1.5 rounded border border-border bg-muted/40 p-2">
+                <label className="text-[11px] font-medium text-muted-foreground" htmlFor={`reject-reason-${suggestion.id}`}>
+                  Reason for rejecting (kept for the audit trail)
+                </label>
+                <Textarea
+                  id={`reject-reason-${suggestion.id}`}
+                  data-testid={`suggestion-reject-reason-${suggestion.id}`}
+                  value={reason}
+                  onChange={(event) => setReason(event.currentTarget.value)}
+                  placeholder="Why is this being rejected?"
+                  rows={2}
+                  className="min-h-[2.25rem] resize-none text-sm"
+                />
+                <div className="flex items-center justify-end gap-1.5">
+                  <Button
+                    type="button"
+                    size="sm"
+                    variant="ghost"
+                    className="h-7 px-2 text-xs"
+                    onClick={() => {
+                      setRejecting(false);
+                      setReason("");
+                    }}
+                  >
+                    Cancel
+                  </Button>
+                  <Button
+                    type="button"
+                    size="sm"
+                    variant="destructive"
+                    className="h-7 px-2 text-xs"
+                    disabled={!reason.trim() || pending != null}
+                    onClick={handleReject}
+                    data-testid={`suggestion-reject-confirm-${suggestion.id}`}
+                  >
+                    Reject suggestion
+                  </Button>
+                </div>
+              </div>
+            ) : null}
+          </div>
+        ) : null}
+      </article>
+    </TooltipProvider>
+  );
+}
+
+function rejectionReason(suggestion: DocumentSuggestionWithComments): string | null {
+  // The reject reason is persisted as a suggestion comment on the server; the
+  // last comment authored at rejection time carries it. Fall back to null.
+  if (suggestion.status !== "rejected") return null;
+  const last = suggestion.comments[suggestion.comments.length - 1];
+  return last?.body ?? null;
+}
+
+function SuggestionDiff({ suggestion }: { suggestion: DocumentSuggestionWithComments }) {
+  const { kind, selectedText, proposedText, insertionPosition } = suggestion;
+  if (kind === "insertion") {
+    return (
+      <div className="space-y-1 text-sm">
+        <p className="text-[11px] uppercase tracking-wide text-muted-foreground">
+          Insert {insertionPosition ? `${insertionPosition} ` : ""}selection
+        </p>
+        <SuggestionText variant="add">{proposedText ?? ""}</SuggestionText>
+        {selectedText ? (
+          <p className="truncate text-[11px] text-muted-foreground">near “{selectedText}”</p>
+        ) : null}
+      </div>
+    );
+  }
+  if (kind === "deletion") {
+    return (
+      <div className="space-y-1 text-sm">
+        <p className="text-[11px] uppercase tracking-wide text-muted-foreground">Delete</p>
+        <SuggestionText variant="remove">{selectedText}</SuggestionText>
+      </div>
+    );
+  }
+  return (
+    <div className="space-y-1 text-sm">
+      <p className="text-[11px] uppercase tracking-wide text-muted-foreground">Source</p>
+      <SuggestionText variant="remove">{selectedText}</SuggestionText>
+      <p className="text-[11px] uppercase tracking-wide text-muted-foreground">Proposed</p>
+      <SuggestionText variant="add">{proposedText ?? ""}</SuggestionText>
+    </div>
+  );
+}
+
+function SuggestionText({
+  variant,
+  children,
+}: {
+  variant: "add" | "remove";
+  children: string;
+}) {
+  return (
+    <p
+      data-variant={variant}
+      className={cn(
+        "whitespace-pre-wrap break-words rounded px-1.5 py-1 text-sm",
+        variant === "add"
+          ? "bg-[var(--paperclip-doc-suggestion-insert-bg)] text-[var(--paperclip-doc-suggestion-insert-fg)]"
+          : "bg-[var(--paperclip-doc-suggestion-delete-bg)] text-[var(--paperclip-doc-suggestion-delete-fg)] line-through",
+      )}
+    >
+      <span aria-hidden="true" className="mr-1 font-bold">
+        {variant === "add" ? "+" : "−"}
+      </span>
+      {children}
+    </p>
+  );
+}
diff --git a/ui/src/index.css b/ui/src/index.css
index 340fff5c398..02f9353bc76 100644
--- a/ui/src/index.css
+++ b/ui/src/index.css
@@ -93,6 +93,12 @@
   --paperclip-doc-annotation-highlight-focused: #fde047;
   --paperclip-doc-annotation-highlight-stale: #fef08a;
   --paperclip-doc-annotation-highlight-resolved: #fef9c3;
+  /* Suggested-edit (CriticMarkup-style) treatments — see PAP-10520 ux-spec §5.4. */
+  --paperclip-doc-suggestion-insert-bg: oklch(0.93 0.08 145);
+  --paperclip-doc-suggestion-insert-fg: oklch(0.3 0.12 145);
+  --paperclip-doc-suggestion-delete-bg: oklch(0.93 0.08 27);
+  --paperclip-doc-suggestion-delete-fg: oklch(0.3 0.2 27);
+  --paperclip-doc-annotation-stale-underline: oklch(0.55 0.18 50);
 }
 
 .dark {
@@ -144,6 +150,12 @@
   --paperclip-doc-annotation-highlight-focused: #ca8a04;
   --paperclip-doc-annotation-highlight-stale: #854d0e;
   --paperclip-doc-annotation-highlight-resolved: #713f12;
+  /* Dark-mode suggestion treatments: drop L to ~0.30, keep chroma. */
+  --paperclip-doc-suggestion-insert-bg: oklch(0.3 0.08 145);
+  --paperclip-doc-suggestion-insert-fg: oklch(0.9 0.1 145);
+  --paperclip-doc-suggestion-delete-bg: oklch(0.3 0.09 27);
+  --paperclip-doc-suggestion-delete-fg: oklch(0.9 0.12 27);
+  --paperclip-doc-annotation-stale-underline: oklch(0.7 0.16 50);
 }
 
 ::highlight(paperclip-doc-annotation-open) {
diff --git a/ui/src/lib/document-review-authors.ts b/ui/src/lib/document-review-authors.ts
new file mode 100644
index 00000000000..bb07b1155e7
--- /dev/null
+++ b/ui/src/lib/document-review-authors.ts
@@ -0,0 +1,41 @@
+import type { Agent, IssueCommentAuthorType } from "@paperclipai/shared";
+import type { CompanyUserProfile } from "@/lib/company-members";
+
+export interface ReviewAuthorMaps {
+  agentMap?: ReadonlyMap<string, Pick<Agent, "id" | "name">>;
+  userProfileMap?: ReadonlyMap<string, CompanyUserProfile>;
+}
+
+export interface ReviewAuthorRef {
+  authorType?: IssueCommentAuthorType;
+  authorAgentId?: string | null;
+  authorUserId?: string | null;
+  createdByAgentId?: string | null;
+  createdByUserId?: string | null;
+}
+
+export interface ResolvedReviewAuthor {
+  name: string;
+  role: "board" | "agent";
+}
+
+/**
+ * Resolve the display name + role for any document-review entity (annotation
+ * comment, review comment, suggestion, suggestion comment). Falls back to a
+ * truncated id, then to a generic "Agent"/"Board" label. Mirrors the resolver
+ * used by `DocumentAnnotationPanel` so author chips read consistently.
+ */
+export function resolveReviewAuthor(ref: ReviewAuthorRef, maps: ReviewAuthorMaps): ResolvedReviewAuthor {
+  const agentId = ref.authorAgentId ?? ref.createdByAgentId ?? null;
+  const userId = ref.authorUserId ?? ref.createdByUserId ?? null;
+  if (agentId) {
+    const agent = maps.agentMap?.get(agentId);
+    return { name: agent?.name ?? agentId.slice(0, 8), role: "agent" };
+  }
+  if (userId) {
+    const profile = maps.userProfileMap?.get(userId);
+    return { name: profile?.label ?? userId.slice(0, 8), role: "board" };
+  }
+  const isAgent = ref.authorType === "agent";
+  return { name: isAgent ? "Agent" : "Board", role: isAgent ? "agent" : "board" };
+}
diff --git a/ui/src/pages/DocumentDetail.test.tsx b/ui/src/pages/DocumentDetail.test.tsx
new file mode 100644
index 00000000000..c2d3810c438
--- /dev/null
+++ b/ui/src/pages/DocumentDetail.test.tsx
@@ -0,0 +1,219 @@
+// @vitest-environment jsdom
+
+import type { ReactNode } from "react";
+import { flushSync } from "react-dom";
+import { createRoot, type Root } from "react-dom/client";
+import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+import type { CompanyDocument } from "@paperclipai/shared";
+import { ApiError } from "@/api/client";
+import { DocumentDetail } from "./DocumentDetail";
+
+const mocks = vi.hoisted(() => ({
+  documentsApi: { get: vi.fn() },
+  documentReviewsApi: { reviewIndex: vi.fn() },
+  documentAnnotationsApi: {},
+  issuesApi: {},
+  agentsApi: { list: vi.fn() },
+  accessApi: { listUserDirectory: vi.fn() },
+  authApi: { getSession: vi.fn() },
+  setBreadcrumbs: vi.fn(),
+  params: { value: { documentId: "doc-1" } as { documentId?: string } },
+}));
+
+vi.mock("react-router-dom", () => ({ useParams: () => mocks.params.value }));
+vi.mock("@/lib/router", () => ({
+  Link: ({ children, to }: { children: ReactNode; to: string }) => <a href={to}>{children}</a>,
+}));
+vi.mock("@/context/CompanyContext", () => ({ useCompany: () => ({ selectedCompanyId: "company-1" }) }));
+vi.mock("@/context/BreadcrumbContext", () => ({ useBreadcrumbs: () => ({ setBreadcrumbs: mocks.setBreadcrumbs }) }));
+vi.mock("@/api/documents", () => ({ documentsApi: mocks.documentsApi }));
+vi.mock("@/api/document-reviews", () => ({ documentReviewsApi: mocks.documentReviewsApi }));
+vi.mock("@/api/document-annotations", () => ({ documentAnnotationsApi: mocks.documentAnnotationsApi }));
+vi.mock("@/api/issues", () => ({ issuesApi: mocks.issuesApi }));
+vi.mock("@/api/agents", () => ({ agentsApi: mocks.agentsApi }));
+vi.mock("@/api/access", () => ({ accessApi: mocks.accessApi }));
+vi.mock("@/api/auth", () => ({ authApi: mocks.authApi }));
+vi.mock("@/components/MarkdownBody", () => ({ MarkdownBody: ({ children }: { children: string }) => <div>{children}</div> }));
+vi.mock("@/components/MarkdownEditor", () => ({ MarkdownEditor: () => <textarea data-testid="md-editor" /> }));
+vi.mock("@/components/DocumentAnnotationLayer", () => ({ DocumentAnnotationLayer: () => null }));
+vi.mock("@/components/DocumentDiffModal", () => ({ DocumentDiffModal: () => null }));
+
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+(globalThis as any).IS_REACT_ACT_ENVIRONMENT = true;
+
+async function act(callback: () => void | Promise<void>) {
+  let result: void | Promise<void> = undefined;
+  flushSync(() => {
+    result = callback();
+  });
+  await result;
+}
+
+async function waitFor(predicate: () => boolean, label: string) {
+  for (let i = 0; i < 50; i += 1) {
+    if (predicate()) return;
+    // eslint-disable-next-line no-await-in-loop
+    await act(async () => {
+      await new Promise((resolve) => setTimeout(resolve, 0));
+    });
+  }
+  throw new Error(`waitFor timed out: ${label}`);
+}
+
+function makeDoc(overrides: Partial<CompanyDocument> = {}): CompanyDocument {
+  return {
+    id: "doc-1",
+    companyId: "company-1",
+    title: "Paperclip Documents review flow",
+    format: "markdown",
+    status: "in_review",
+    documentType: "spec",
+    summary: null,
+    ownerAgentId: "agent-1",
+    ownerUserId: null,
+    latestRevisionId: "rev-12",
+    latestRevisionNumber: 12,
+    createdByAgentId: "agent-1",
+    createdByUserId: null,
+    updatedByAgentId: "agent-1",
+    updatedByUserId: null,
+    lockedAt: null,
+    lockedByAgentId: null,
+    lockedByUserId: null,
+    sourceTrust: null,
+    archivedAt: null,
+    archivedByAgentId: null,
+    archivedByUserId: null,
+    createdAt: new Date("2026-06-01T00:00:00Z"),
+    updatedAt: new Date("2026-06-06T00:00:00Z"),
+    backlinks: [
+      {
+        id: "link-1",
+        companyId: "company-1",
+        documentId: "doc-1",
+        targetType: "issue",
+        targetId: "issue-1",
+        relationship: "source",
+        issueDocumentId: "idoc-1",
+        issueDocumentKey: "spec",
+        title: "Design Paperclip Documents UX",
+        identifier: "PAP-10520",
+        createdAt: new Date("2026-06-01T00:00:00Z"),
+        updatedAt: new Date("2026-06-01T00:00:00Z"),
+      },
+    ],
+    feedbackCounts: {
+      openComments: 1,
+      resolvedComments: 0,
+      openReviewThreads: 0,
+      resolvedReviewThreads: 0,
+      pendingSuggestions: 0,
+      acceptedSuggestions: 0,
+      rejectedSuggestions: 0,
+      staleAnchors: 0,
+      orphanedAnchors: 0,
+    },
+    body: "# Heading\n\nBody text here.",
+    ...overrides,
+  };
+}
+
+const emptyIndex = {
+  issueId: "issue-1",
+  documentId: "doc-1",
+  documentKey: "spec",
+  latestRevisionId: "rev-12",
+  latestRevisionNumber: 12,
+  counts: {
+    unresolved: 0,
+    openAnchoredThreads: 0,
+    openReviewThreads: 0,
+    pendingSuggestions: 0,
+    resolvedAnchoredThreads: 0,
+    resolvedReviewThreads: 0,
+    acceptedSuggestions: 0,
+    rejectedSuggestions: 0,
+    staleAnchors: 0,
+    orphanedAnchors: 0,
+  },
+  annotationThreads: [],
+  reviewThreads: [],
+  suggestions: [],
+};
+
+let container: HTMLDivElement;
+let root: Root;
+
+function renderPage() {
+  const client = new QueryClient({ defaultOptions: { queries: { retry: false } } });
+  return act(() =>
+    root.render(
+      <QueryClientProvider client={client}>
+        <DocumentDetail />
+      </QueryClientProvider>,
+    ),
+  );
+}
+
+beforeEach(() => {
+  container = document.createElement("div");
+  document.body.appendChild(container);
+  root = createRoot(container);
+  mocks.params.value = { documentId: "doc-1" };
+  mocks.agentsApi.list.mockResolvedValue([{ id: "agent-1", name: "ClaudeCoder" }]);
+  mocks.accessApi.listUserDirectory.mockResolvedValue({ users: [] });
+  mocks.authApi.getSession.mockResolvedValue({ user: { id: "user-1" } });
+  mocks.documentReviewsApi.reviewIndex.mockResolvedValue(emptyIndex);
+});
+
+afterEach(() => {
+  act(() => root.unmount());
+  container.remove();
+  vi.clearAllMocks();
+});
+
+describe("DocumentDetail", () => {
+  it("shows a permission-denied state without leaking the title", async () => {
+    mocks.documentsApi.get.mockRejectedValue(new ApiError("Forbidden", 403, null));
+    await renderPage();
+    await waitFor(() => container.textContent?.includes("don't have access") ?? false, "permission denied");
+    expect(container.textContent).toContain("You don't have access to this document.");
+    expect(container.textContent).not.toContain("Paperclip Documents review flow");
+  });
+
+  it("renders the header, body, and review rail for a board user", async () => {
+    mocks.documentsApi.get.mockResolvedValue(makeDoc());
+    await renderPage();
+    await waitFor(() => container.textContent?.includes("Paperclip Documents review flow") ?? false, "title");
+    // Header pieces
+    expect(container.textContent).toContain("Spec");
+    expect(container.textContent).toContain("Rev 12");
+    expect(container.querySelector('[data-testid="action-edit"]')).not.toBeNull();
+    expect(container.querySelector('[data-testid="action-history"]')).not.toBeNull();
+    // Backlink chip
+    expect(container.textContent).toContain("PAP-10520");
+    // Body
+    expect(container.textContent).toContain("Body text here.");
+    // Rail
+    expect(container.querySelector('[data-testid="document-review-rail"]')).not.toBeNull();
+  });
+
+  it("treats signed-out viewers as read-only", async () => {
+    mocks.authApi.getSession.mockResolvedValue(null);
+    mocks.documentsApi.get.mockResolvedValue(makeDoc());
+    await renderPage();
+    await waitFor(() => container.textContent?.includes("Paperclip Documents review flow") ?? false, "title");
+    expect(container.querySelector('[data-testid="readonly-badge"]')).not.toBeNull();
+    const edit = container.querySelector<HTMLButtonElement>('[data-testid="action-edit"]');
+    expect(edit?.disabled).toBe(true);
+  });
+
+  it("shows a locked-by-other badge and disables Edit", async () => {
+    mocks.documentsApi.get.mockResolvedValue(makeDoc({ lockedByAgentId: "agent-1", lockedAt: new Date() }));
+    await renderPage();
+    await waitFor(() => container.textContent?.includes("Paperclip Documents review flow") ?? false, "title");
+    expect(container.querySelector('[data-testid="locked-by-other"]')).not.toBeNull();
+    expect(container.querySelector<HTMLButtonElement>('[data-testid="action-edit"]')?.disabled).toBe(true);
+  });
+});
diff --git a/ui/src/pages/DocumentDetail.tsx b/ui/src/pages/DocumentDetail.tsx
new file mode 100644
index 00000000000..1348d7dc4d6
--- /dev/null
+++ b/ui/src/pages/DocumentDetail.tsx
@@ -0,0 +1,833 @@
+import { useCallback, useEffect, useMemo, useRef, useState } from "react";
+import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
+import { useParams } from "react-router-dom";
+import type {
+  Agent,
+  CompanyDocument,
+  DocumentSuggestionKind,
+  DocumentSuggestionWithComments,
+  DocumentType,
+} from "@paperclipai/shared";
+import {
+  AlertTriangle,
+  BarChart3,
+  BookOpen,
+  ClipboardList,
+  FileText,
+  History,
+  Link2,
+  ListTodo,
+  Lock,
+  LockOpen,
+  MessageSquare,
+  Pencil,
+} from "lucide-react";
+import { ApiError } from "@/api/client";
+import { documentsApi } from "@/api/documents";
+import { documentReviewsApi } from "@/api/document-reviews";
+import { documentAnnotationsApi } from "@/api/document-annotations";
+import { issuesApi } from "@/api/issues";
+import { agentsApi } from "@/api/agents";
+import { accessApi } from "@/api/access";
+import { authApi } from "@/api/auth";
+import { useCompany } from "@/context/CompanyContext";
+import { useBreadcrumbs } from "@/context/BreadcrumbContext";
+import { queryKeys } from "@/lib/queryKeys";
+import { buildCompanyUserProfileMap } from "@/lib/company-members";
+import { cn, relativeTime } from "@/lib/utils";
+import { EmptyState } from "@/components/EmptyState";
+import { StatusBadge } from "@/components/StatusBadge";
+import { Identity } from "@/components/Identity";
+import { Badge } from "@/components/ui/badge";
+import { Button } from "@/components/ui/button";
+import { Textarea } from "@/components/ui/textarea";
+import {
+  Dialog,
+  DialogContent,
+  DialogFooter,
+  DialogHeader,
+  DialogTitle,
+} from "@/components/ui/dialog";
+import {
+  DropdownMenu,
+  DropdownMenuContent,
+  DropdownMenuItem,
+  DropdownMenuTrigger,
+} from "@/components/ui/dropdown-menu";
+import {
+  Tooltip,
+  TooltipContent,
+  TooltipProvider,
+  TooltipTrigger,
+} from "@/components/ui/tooltip";
+import { Link } from "@/lib/router";
+import { MarkdownBody } from "@/components/MarkdownBody";
+import { MarkdownEditor } from "@/components/MarkdownEditor";
+import {
+  DocumentAnnotationLayer,
+  type AnnotationOverlayThread,
+  type PendingAnchor,
+} from "@/components/DocumentAnnotationLayer";
+import { DocumentDiffModal } from "@/components/DocumentDiffModal";
+import { DocumentReviewRail } from "@/components/documents/DocumentReviewRail";
+import { SelectionToolbar, type SuggestionDraftIntent } from "@/components/documents/SelectionToolbar";
+import type { RailThread } from "@/components/documents/DocumentThreadCard";
+
+const DOC_TYPE_ICON: Record<DocumentType, typeof FileText> = {
+  plan: ListTodo,
+  spec: BookOpen,
+  brief: ClipboardList,
+  report: BarChart3,
+  other: FileText,
+};
+
+const DOC_TYPE_LABEL: Record<DocumentType, string> = {
+  plan: "Plan",
+  spec: "Spec",
+  brief: "Brief",
+  report: "Report",
+  other: "Document",
+};
+
+interface IssueBinding {
+  issueId: string;
+  key: string;
+}
+
+/** Resolve the issue + document key the review index is keyed by. */
+function resolveIssueBinding(doc: CompanyDocument | undefined): IssueBinding | null {
+  if (!doc) return null;
+  const link = doc.backlinks.find((b) => b.issueDocumentKey && b.targetType === "issue");
+  if (!link?.issueDocumentKey) return null;
+  return { issueId: link.targetId, key: link.issueDocumentKey };
+}
+
+export function DocumentDetail() {
+  const { documentId } = useParams<{ documentId: string }>();
+  const { selectedCompanyId } = useCompany();
+  const { setBreadcrumbs } = useBreadcrumbs();
+  const queryClient = useQueryClient();
+
+  const [editMode, setEditMode] = useState(false);
+  const [draft, setDraft] = useState("");
+  const [baseRevisionId, setBaseRevisionId] = useState<string | null>(null);
+  const [conflict, setConflict] = useState(false);
+  const [diffOpen, setDiffOpen] = useState(false);
+  const [railOpen, setRailOpen] = useState(false);
+  const [isMobile, setIsMobile] = useState(false);
+  const [commentDraft, setCommentDraft] = useState<{ anchor: PendingAnchor } | null>(null);
+  const [commentBody, setCommentBody] = useState("");
+  const [suggestDraft, setSuggestDraft] = useState<{ anchor: PendingAnchor; intent: SuggestionDraftIntent } | null>(null);
+  const [proposed, setProposed] = useState("");
+  const containerRef = useRef<HTMLElement | null>(null);
+
+  useEffect(() => {
+    if (typeof window === "undefined" || typeof window.matchMedia !== "function") return;
+    const mq = window.matchMedia("(max-width: 1023px)");
+    const handler = () => setIsMobile(mq.matches);
+    handler();
+    mq.addEventListener?.("change", handler);
+    return () => mq.removeEventListener?.("change", handler);
+  }, []);
+
+  const documentQuery = useQuery({
+    queryKey: queryKeys.documents.detail(selectedCompanyId ?? "", documentId ?? ""),
+    queryFn: () => documentsApi.get(selectedCompanyId!, documentId!),
+    enabled: !!selectedCompanyId && !!documentId,
+    retry: (count, error) => !(error instanceof ApiError && [403, 404].includes(error.status)) && count < 2,
+  });
+  const doc = documentQuery.data;
+  const binding = useMemo(() => resolveIssueBinding(doc), [doc]);
+
+  const { data: agents } = useQuery({
+    queryKey: queryKeys.agents.list(selectedCompanyId ?? ""),
+    queryFn: () => agentsApi.list(selectedCompanyId!),
+    enabled: !!selectedCompanyId,
+  });
+  const { data: members } = useQuery({
+    queryKey: queryKeys.access.companyUserDirectory(selectedCompanyId ?? ""),
+    queryFn: () => accessApi.listUserDirectory(selectedCompanyId!),
+    enabled: !!selectedCompanyId,
+  });
+  const { data: session } = useQuery({ queryKey: queryKeys.auth.session, queryFn: () => authApi.getSession() });
+
+  const reviewIndexQuery = useQuery({
+    queryKey: binding ? queryKeys.documents.reviewIndex(binding.issueId, binding.key) : ["documents", "review-index", "none"],
+    queryFn: () => documentReviewsApi.reviewIndex(binding!.issueId, binding!.key, { status: "all", includeComments: true }),
+    enabled: !!binding,
+  });
+  const reviewIndex = reviewIndexQuery.data;
+
+  const agentMap = useMemo(() => {
+    const map = new Map<string, Pick<Agent, "id" | "name">>();
+    for (const agent of agents ?? []) map.set(agent.id, agent);
+    return map;
+  }, [agents]);
+  const userProfileMap = useMemo(() => buildCompanyUserProfileMap(members?.users), [members?.users]);
+  const authorMaps = useMemo(() => ({ agentMap, userProfileMap }), [agentMap, userProfileMap]);
+
+  const currentUserId = session?.user?.id ?? null;
+  const isBoard = !!currentUserId;
+  const lockedByMe = !!doc?.lockedByUserId && doc.lockedByUserId === currentUserId;
+  const lockedByOther = !!(doc?.lockedByAgentId || doc?.lockedByUserId) && !lockedByMe;
+  const isArchived = doc?.status === "archived";
+  const canReview = isBoard;
+  const canEdit = isBoard && !lockedByOther && !isArchived;
+
+  const ownerAgent = doc?.ownerAgentId ? agentMap.get(doc.ownerAgentId) : undefined;
+  const lockHolderName = doc?.lockedByAgentId
+    ? agentMap.get(doc.lockedByAgentId)?.name ?? "an agent"
+    : doc?.lockedByUserId
+      ? userProfileMap.get(doc.lockedByUserId)?.label ?? "a board member"
+      : null;
+
+  useEffect(() => {
+    setBreadcrumbs([
+      { label: "Documents", href: "/documents" },
+      { label: doc?.title ?? "Document" },
+    ]);
+  }, [setBreadcrumbs, doc?.title]);
+
+  const invalidateReview = useCallback(() => {
+    if (binding) {
+      queryClient.invalidateQueries({ queryKey: queryKeys.documents.reviewIndex(binding.issueId, binding.key) });
+    }
+  }, [binding, queryClient]);
+  const invalidateDoc = useCallback(() => {
+    queryClient.invalidateQueries({
+      queryKey: queryKeys.documents.detail(selectedCompanyId ?? "", documentId ?? ""),
+    });
+  }, [queryClient, selectedCompanyId, documentId]);
+
+  // --- Mutations -------------------------------------------------------------
+  const createComment = useMutation({
+    mutationFn: (input: { anchor: PendingAnchor; body: string }) =>
+      documentAnnotationsApi.create(binding!.issueId, binding!.key, {
+        baseRevisionId: doc!.latestRevisionId!,
+        baseRevisionNumber: doc!.latestRevisionNumber,
+        selector: input.anchor.selector,
+        body: input.body,
+      }),
+    onSuccess: () => {
+      setCommentDraft(null);
+      setCommentBody("");
+      invalidateReview();
+    },
+  });
+
+  const createSuggestion = useMutation({
+    mutationFn: (input: { anchor: PendingAnchor; intent: SuggestionDraftIntent; proposedText: string | null }) =>
+      documentReviewsApi.createSuggestion(binding!.issueId, binding!.key, {
+        baseRevisionId: doc!.latestRevisionId!,
+        baseRevisionNumber: doc!.latestRevisionNumber,
+        kind: input.intent.kind,
+        selector: input.anchor.selector,
+        proposedText: input.proposedText,
+        insertionPosition: input.intent.insertionPosition ?? null,
+      }),
+    onSuccess: () => {
+      setSuggestDraft(null);
+      setProposed("");
+      invalidateReview();
+    },
+  });
+
+  const lockMutation = useMutation({
+    mutationFn: (lock: boolean) =>
+      lock
+        ? issuesApi.lockDocument(binding!.issueId, binding!.key)
+        : issuesApi.unlockDocument(binding!.issueId, binding!.key),
+    onSuccess: invalidateDoc,
+  });
+
+  const saveMutation = useMutation({
+    mutationFn: (body: string) =>
+      issuesApi.upsertDocument(binding!.issueId, binding!.key, {
+        format: "markdown",
+        body,
+        baseRevisionId,
+      }),
+    onSuccess: () => {
+      setEditMode(false);
+      setConflict(false);
+      invalidateDoc();
+      invalidateReview();
+    },
+    onError: (error) => {
+      if (error instanceof ApiError && error.status === 409) setConflict(true);
+    },
+  });
+
+  // Rail handlers
+  const replyThread = useCallback(
+    async (thread: RailThread, body: string) => {
+      if (!binding) return;
+      if (thread.kind === "overall") {
+        await documentReviewsApi.addReviewComment(binding.issueId, binding.key, thread.id, { body });
+      } else {
+        await documentAnnotationsApi.addComment(binding.issueId, binding.key, thread.id, { body });
+      }
+      invalidateReview();
+    },
+    [binding, invalidateReview],
+  );
+
+  const toggleThreadResolved = useCallback(
+    async (thread: RailThread, resolved: boolean) => {
+      if (!binding) return;
+      const status = resolved ? "resolved" : "open";
+      if (thread.kind === "overall") {
+        await documentReviewsApi.updateReviewThreadStatus(binding.issueId, binding.key, thread.id, status);
+      } else {
+        await documentAnnotationsApi.updateStatus(binding.issueId, binding.key, thread.id, status);
+      }
+      invalidateReview();
+    },
+    [binding, invalidateReview],
+  );
+
+  const addOverallComment = useCallback(
+    async (body: string) => {
+      if (!binding) return;
+      await documentReviewsApi.createReviewThread(binding.issueId, binding.key, { body });
+      invalidateReview();
+    },
+    [binding, invalidateReview],
+  );
+
+  const acceptSuggestion = useCallback(
+    async (suggestion: DocumentSuggestionWithComments) => {
+      if (!binding || !doc?.latestRevisionId) return;
+      await documentReviewsApi.acceptSuggestion(binding.issueId, binding.key, suggestion.id, {
+        baseRevisionId: doc.latestRevisionId,
+      });
+      invalidateReview();
+      invalidateDoc();
+    },
+    [binding, doc?.latestRevisionId, invalidateReview, invalidateDoc],
+  );
+
+  const rejectSuggestion = useCallback(
+    async (suggestion: DocumentSuggestionWithComments, reason: string) => {
+      if (!binding) return;
+      await documentReviewsApi.rejectSuggestion(binding.issueId, binding.key, suggestion.id, { reason });
+      invalidateReview();
+    },
+    [binding, invalidateReview],
+  );
+
+  const replySuggestion = useCallback(
+    async (suggestion: DocumentSuggestionWithComments, body: string) => {
+      if (!binding) return;
+      await documentReviewsApi.addSuggestionComment(binding.issueId, binding.key, suggestion.id, { body });
+      invalidateReview();
+    },
+    [binding, invalidateReview],
+  );
+
+  const startEdit = useCallback(() => {
+    if (!doc) return;
+    setDraft(doc.body);
+    setBaseRevisionId(doc.latestRevisionId);
+    setConflict(false);
+    setEditMode(true);
+  }, [doc]);
+
+  const overlayThreads = useMemo<AnnotationOverlayThread[]>(
+    () =>
+      (reviewIndex?.annotationThreads ?? []).map((thread) => ({
+        id: thread.id,
+        selectedText: thread.selectedText,
+        status: thread.status,
+        anchorState: thread.anchorState,
+      })),
+    [reviewIndex?.annotationThreads],
+  );
+
+  // --- Render guards ---------------------------------------------------------
+  if (!selectedCompanyId) {
+    return <EmptyState icon={FileText} message="Select a company to view this document." />;
+  }
+  if (documentQuery.error instanceof ApiError && [403, 404].includes(documentQuery.error.status)) {
+    return (
+      <EmptyState
+        icon={Lock}
+        message="You don't have access to this document."
+        action="Back to your documents"
+        onAction={() => {
+          window.location.href = window.location.pathname.replace(/\/documents\/.*/, "/documents");
+        }}
+      />
+    );
+  }
+  if (documentQuery.isLoading || !doc) {
+    return <DocumentDetailSkeleton />;
+  }
+
+  const TypeIcon = DOC_TYPE_ICON[doc.documentType] ?? FileText;
+  const staleBase = !editMode && baseRevisionId != null && baseRevisionId !== doc.latestRevisionId;
+  const showConflictBanner = conflict || staleBase;
+
+  return (
+    <TooltipProvider delayDuration={200}>
+      <div className="flex h-full min-h-0 w-full flex-col lg:flex-row">
+        {/* Center column */}
+        <div className="flex min-w-0 flex-1 flex-col overflow-y-auto">
+          <DocumentHeader
+            doc={doc}
+            TypeIcon={TypeIcon}
+            ownerName={ownerAgent?.name ?? null}
+            canEdit={canEdit}
+            isBoard={isBoard}
+            editMode={editMode}
+            lockedByMe={lockedByMe}
+            lockedByOther={lockedByOther}
+            lockHolderName={lockHolderName}
+            onEdit={startEdit}
+            onHistory={() => setDiffOpen(true)}
+            onToggleLock={() => lockMutation.mutate(!lockedByMe)}
+            lockPending={lockMutation.isPending}
+          />
+
+          {showConflictBanner ? (
+            <div
+              role="alert"
+              data-testid="document-conflict-banner"
+              className="mx-4 mb-3 flex flex-wrap items-center gap-2 rounded-md border border-amber-300 bg-amber-50 px-3 py-2 text-sm text-amber-800 dark:border-amber-800 dark:bg-amber-950/40 dark:text-amber-200"
+            >
+              <AlertTriangle className="h-4 w-4 shrink-0" aria-hidden="true" />
+              <span className="flex-1">Someone updated this document while you were editing.</span>
+              <Button size="sm" variant="outline" className="h-7 text-xs" onClick={() => setDiffOpen(true)}>
+                View their changes
+              </Button>
+              <Button
+                size="sm"
+                variant="outline"
+                className="h-7 text-xs"
+                onClick={() => {
+                  setBaseRevisionId(doc.latestRevisionId);
+                  setConflict(false);
+                }}
+              >
+                Rebase my draft
+              </Button>
+              <Button
+                size="sm"
+                variant="ghost"
+                className="h-7 text-xs text-destructive hover:text-destructive"
+                onClick={() => {
+                  setDraft(doc.body);
+                  setBaseRevisionId(doc.latestRevisionId);
+                  setConflict(false);
+                  setEditMode(false);
+                }}
+              >
+                Discard mine
+              </Button>
+            </div>
+          ) : null}
+
+          <div className="px-4 pb-24 lg:pb-8">
+            <div className="mx-auto w-full max-w-[78ch]">
+              {editMode ? (
+                <div className="space-y-3">
+                  <MarkdownEditor value={draft} onChange={setDraft} />
+                  <div className="flex items-center justify-end gap-2">
+                    <Button variant="ghost" size="sm" onClick={() => setEditMode(false)}>
+                      Cancel
+                    </Button>
+                    <Button
+                      size="sm"
+                      disabled={saveMutation.isPending}
+                      onClick={() => saveMutation.mutate(draft)}
+                    >
+                      Save draft
+                    </Button>
+                  </div>
+                </div>
+              ) : (
+                <section
+                  ref={(el) => {
+                    containerRef.current = el;
+                  }}
+                  className="relative min-w-0"
+                  data-testid="document-detail-body"
+                >
+                  <div className="relative z-[1]">
+                    <MarkdownBody>{doc.body}</MarkdownBody>
+                  </div>
+                  {doc.latestRevisionId && binding ? (
+                    <DocumentAnnotationLayer
+                      containerRef={containerRef}
+                      markdown={doc.body}
+                      threads={overlayThreads}
+                      focusedThreadId={null}
+                      onThreadFocus={() => setRailOpen(true)}
+                      pendingAnchor={null}
+                      onPendingAnchorChange={() => {}}
+                      onRequestComment={(anchor) => {
+                        setCommentDraft({ anchor });
+                        setCommentBody("");
+                      }}
+                      newCommentDisabled={!canReview}
+                      newCommentDisabledReason={canReview ? null : "Sign in to leave feedback."}
+                      hideResolved
+                      renderSelectionToolbar={({ anchor, clear }) => (
+                        <SelectionToolbar
+                          onComment={() => {
+                            setCommentDraft({ anchor });
+                            setCommentBody("");
+                            clear();
+                          }}
+                          onSuggest={(intent) => {
+                            if (intent.kind === "deletion") {
+                              createSuggestion.mutate({ anchor, intent, proposedText: null });
+                            } else {
+                              setSuggestDraft({ anchor, intent });
+                              setProposed("");
+                            }
+                            clear();
+                          }}
+                          commentDisabled={!canReview}
+                          commentDisabledReason="Sign in to leave feedback."
+                          suggestDisabled={!canReview}
+                          suggestDisabledReason="Sign in to suggest edits."
+                        />
+                      )}
+                    />
+                  ) : null}
+                </section>
+              )}
+            </div>
+          </div>
+        </div>
+
+        {/* Desktop rail */}
+        {!isMobile ? (
+          <div className="hidden w-[360px] shrink-0 lg:block">
+            <DocumentReviewRail
+              reviewIndex={reviewIndex}
+              loading={reviewIndexQuery.isLoading}
+              canReview={canReview}
+              canFinishReview={canEdit}
+              latestRevisionId={doc.latestRevisionId}
+              authorMaps={authorMaps}
+              onReplyThread={replyThread}
+              onToggleThreadResolved={toggleThreadResolved}
+              onAddOverallComment={canReview ? addOverallComment : undefined}
+              onAcceptSuggestion={acceptSuggestion}
+              onRejectSuggestion={rejectSuggestion}
+              onReplySuggestion={replySuggestion}
+              onViewSuggestionDiff={() => setDiffOpen(true)}
+            />
+          </div>
+        ) : null}
+
+        {/* Mobile FAB + sheet */}
+        {isMobile ? (
+          <>
+            <button
+              type="button"
+              data-testid="document-rail-fab"
+              onClick={() => setRailOpen(true)}
+              className="fixed bottom-4 left-1/2 z-50 flex -translate-x-1/2 items-center gap-2 rounded-full border border-border bg-popover px-4 py-2 text-sm shadow-lg"
+            >
+              <MessageSquare className="h-4 w-4" aria-hidden="true" />
+              {(reviewIndex?.counts.openAnchoredThreads ?? 0) + (reviewIndex?.counts.openReviewThreads ?? 0)}
+              <Pencil className="h-4 w-4" aria-hidden="true" />
+              {reviewIndex?.counts.pendingSuggestions ?? 0}
+            </button>
+            <DocumentReviewRail
+              isMobile
+              open={railOpen}
+              onOpenChange={setRailOpen}
+              reviewIndex={reviewIndex}
+              loading={reviewIndexQuery.isLoading}
+              canReview={canReview}
+              canFinishReview={canEdit}
+              latestRevisionId={doc.latestRevisionId}
+              authorMaps={authorMaps}
+              onReplyThread={replyThread}
+              onToggleThreadResolved={toggleThreadResolved}
+              onAddOverallComment={canReview ? addOverallComment : undefined}
+              onAcceptSuggestion={acceptSuggestion}
+              onRejectSuggestion={rejectSuggestion}
+              onReplySuggestion={replySuggestion}
+              onViewSuggestionDiff={() => setDiffOpen(true)}
+            />
+          </>
+        ) : null}
+      </div>
+
+      {/* Comment composer */}
+      <Dialog open={!!commentDraft} onOpenChange={(open) => !open && setCommentDraft(null)}>
+        <DialogContent>
+          <DialogHeader>
+            <DialogTitle>Comment on selection</DialogTitle>
+          </DialogHeader>
+          {commentDraft ? (
+            <p className="mb-2 border-l-2 border-border pl-2 text-xs italic text-muted-foreground">
+              “{commentDraft.anchor.selectedText}”
+            </p>
+          ) : null}
+          <Textarea
+            data-testid="comment-composer"
+            value={commentBody}
+            onChange={(e) => setCommentBody(e.currentTarget.value)}
+            placeholder="Add your comment…"
+            rows={4}
+          />
+          <DialogFooter>
+            <Button variant="ghost" onClick={() => setCommentDraft(null)}>
+              Cancel
+            </Button>
+            <Button
+              disabled={!commentBody.trim() || createComment.isPending}
+              onClick={() => commentDraft && createComment.mutate({ anchor: commentDraft.anchor, body: commentBody.trim() })}
+            >
+              Comment
+            </Button>
+          </DialogFooter>
+        </DialogContent>
+      </Dialog>
+
+      {/* Suggestion composer */}
+      <Dialog open={!!suggestDraft} onOpenChange={(open) => !open && setSuggestDraft(null)}>
+        <DialogContent>
+          <DialogHeader>
+            <DialogTitle>{suggestionDialogTitle(suggestDraft?.intent.kind)}</DialogTitle>
+          </DialogHeader>
+          {suggestDraft ? (
+            <p className="mb-2 border-l-2 border-border pl-2 text-xs italic text-muted-foreground">
+              “{suggestDraft.anchor.selectedText}”
+            </p>
+          ) : null}
+          <Textarea
+            data-testid="suggestion-composer"
+            value={proposed}
+            onChange={(e) => setProposed(e.currentTarget.value)}
+            placeholder="Proposed text…"
+            rows={4}
+          />
+          <DialogFooter>
+            <Button variant="ghost" onClick={() => setSuggestDraft(null)}>
+              Cancel
+            </Button>
+            <Button
+              disabled={!proposed.trim() || createSuggestion.isPending}
+              onClick={() =>
+                suggestDraft &&
+                createSuggestion.mutate({ anchor: suggestDraft.anchor, intent: suggestDraft.intent, proposedText: proposed.trim() })
+              }
+            >
+              Suggest edit
+            </Button>
+          </DialogFooter>
+        </DialogContent>
+      </Dialog>
+
+      {binding ? (
+        <DocumentDiffModal
+          issueId={binding.issueId}
+          documentKey={binding.key}
+          latestRevisionNumber={doc.latestRevisionNumber}
+          open={diffOpen}
+          onOpenChange={setDiffOpen}
+        />
+      ) : null}
+    </TooltipProvider>
+  );
+}
+
+function suggestionDialogTitle(kind?: DocumentSuggestionKind): string {
+  if (kind === "insertion") return "Insert text";
+  if (kind === "deletion") return "Delete selection";
+  return "Replace selection";
+}
+
+interface DocumentHeaderProps {
+  doc: CompanyDocument;
+  TypeIcon: typeof FileText;
+  ownerName: string | null;
+  canEdit: boolean;
+  isBoard: boolean;
+  editMode: boolean;
+  lockedByMe: boolean;
+  lockedByOther: boolean;
+  lockHolderName: string | null;
+  onEdit: () => void;
+  onHistory: () => void;
+  onToggleLock: () => void;
+  lockPending: boolean;
+}
+
+function DocumentHeader({
+  doc,
+  TypeIcon,
+  ownerName,
+  canEdit,
+  isBoard,
+  editMode,
+  lockedByMe,
+  lockedByOther,
+  lockHolderName,
+  onEdit,
+  onHistory,
+  onToggleLock,
+  lockPending,
+}: DocumentHeaderProps) {
+  const backlinks = doc.backlinks.filter((b) => b.identifier);
+  const shownBacklinks = backlinks.slice(0, 5);
+  const extraBacklinks = backlinks.length - shownBacklinks.length;
+
+  const copyLink = () => {
+    if (typeof navigator !== "undefined" && navigator.clipboard) {
+      navigator.clipboard.writeText(window.location.href).catch(() => {});
+    }
+  };
+
+  return (
+    <header className="px-4 pt-4">
+      <div className="mb-1 flex flex-wrap items-center gap-2">
+        <h1 className="text-xl font-bold text-foreground">{doc.title ?? "Untitled document"}</h1>
+        <StatusBadge status={doc.status} />
+        <span className="inline-flex items-center gap-1 text-xs text-muted-foreground">
+          <TypeIcon className="h-3.5 w-3.5" aria-hidden="true" />
+          {DOC_TYPE_LABEL[doc.documentType]}
+        </span>
+        {ownerName ? (
+          <span className="inline-flex items-center gap-1 text-xs text-muted-foreground">
+            <Identity name={ownerName} size="sm" />
+          </span>
+        ) : null}
+        {!isBoard ? (
+          <Badge className="border-transparent bg-muted px-1.5 py-0 text-[10px] text-muted-foreground" data-testid="readonly-badge">
+            Read-only
+          </Badge>
+        ) : null}
+        {lockedByOther ? (
+          <Badge
+            data-testid="locked-by-other"
+            className="gap-1 border-transparent bg-amber-100 px-1.5 py-0 text-[10px] text-amber-700 dark:bg-amber-900/50 dark:text-amber-300"
+          >
+            <Lock className="h-3 w-3" aria-hidden="true" />
+            Locked by {lockHolderName}
+          </Badge>
+        ) : null}
+        {lockedByMe ? (
+          <Badge className="gap-1 border-transparent bg-muted px-1.5 py-0 text-[10px] text-muted-foreground">
+            <Lock className="h-3 w-3" aria-hidden="true" />
+            Locked by you
+          </Badge>
+        ) : null}
+      </div>
+
+      {/* Action row */}
+      {!editMode ? (
+        <div className="mb-2 flex flex-wrap items-center gap-1.5">
+          <Tooltip>
+            <TooltipTrigger asChild>
+              <span>
+                <Button size="sm" variant="outline" className="h-8" disabled={!canEdit} onClick={onEdit} data-testid="action-edit">
+                  <Pencil className="mr-1 h-3.5 w-3.5" aria-hidden="true" />
+                  Edit
+                </Button>
+              </span>
+            </TooltipTrigger>
+            {!canEdit ? (
+              <TooltipContent>
+                {lockedByOther ? `Locked by ${lockHolderName}` : "You don't have edit access."}
+              </TooltipContent>
+            ) : null}
+          </Tooltip>
+          <Button size="sm" variant="ghost" className="h-8" onClick={onHistory} data-testid="action-history">
+            <History className="mr-1 h-3.5 w-3.5" aria-hidden="true" />
+            History
+          </Button>
+          {isBoard ? (
+            <Button
+              size="sm"
+              variant="ghost"
+              className="h-8"
+              disabled={lockedByOther || lockPending}
+              onClick={onToggleLock}
+              data-testid="action-lock"
+            >
+              {lockedByMe ? (
+                <>
+                  <LockOpen className="mr-1 h-3.5 w-3.5" aria-hidden="true" />
+                  Unlock
+                </>
+              ) : (
+                <>
+                  <Lock className="mr-1 h-3.5 w-3.5" aria-hidden="true" />
+                  Lock
+                </>
+              )}
+            </Button>
+          ) : null}
+          <Button size="sm" variant="ghost" className="h-8" onClick={copyLink} data-testid="action-copy-link">
+            <Link2 className="mr-1 h-3.5 w-3.5" aria-hidden="true" />
+            Copy link
+          </Button>
+          <DropdownMenu>
+            <DropdownMenuTrigger asChild>
+              <Button size="icon-sm" variant="ghost" className="h-8 w-8" aria-label="More actions" data-testid="action-overflow">
+                <span aria-hidden="true">⋯</span>
+              </Button>
+            </DropdownMenuTrigger>
+            <DropdownMenuContent align="end">
+              <DropdownMenuItem disabled>Archive</DropdownMenuItem>
+              <DropdownMenuItem disabled>Manage links…</DropdownMenuItem>
+              <DropdownMenuItem disabled>Export</DropdownMenuItem>
+            </DropdownMenuContent>
+          </DropdownMenu>
+        </div>
+      ) : null}
+
+      {/* Backlinks */}
+      {shownBacklinks.length > 0 ? (
+        <div className="mb-1.5 flex flex-wrap items-center gap-1.5">
+          <span className="text-[11px] text-muted-foreground">Backlinks:</span>
+          {shownBacklinks.map((link) => (
+            <Link key={link.id} to={`/issues/${link.identifier}`}>
+              <Badge variant="outline" className="px-1.5 py-0 text-[10px] font-mono">
+                {link.identifier}
+              </Badge>
+            </Link>
+          ))}
+          {extraBacklinks > 0 ? (
+            <span className="text-[11px] text-muted-foreground">+{extraBacklinks} more</span>
+          ) : null}
+        </div>
+      ) : null}
+
+      {/* Meta row */}
+      <div className="mb-3 flex items-center gap-2 border-b border-border pb-3 text-[11px] text-muted-foreground">
+        <button
+          type="button"
+          onClick={onHistory}
+          className="rounded border border-border px-1.5 py-0.5 font-mono hover:bg-accent/50"
+          data-testid="meta-rev"
+        >
+          Rev {doc.latestRevisionNumber}
+        </button>
+        <span>updated {relativeTime(doc.updatedAt)}</span>
+      </div>
+    </header>
+  );
+}
+
+function DocumentDetailSkeleton() {
+  return (
+    <div className="w-full px-4 py-4" data-testid="document-detail-skeleton">
+      <div className="mb-3 h-7 w-1/2 animate-pulse rounded bg-muted" />
+      <div className="mb-2 h-8 w-72 animate-pulse rounded bg-muted" />
+      <div className="space-y-2">
+        {[0, 1, 2, 3, 4].map((i) => (
+          <div key={i} className="h-4 w-full animate-pulse rounded bg-muted/60" />
+        ))}
+      </div>
+    </div>
+  );
+}
diff --git a/ui/storybook/stories/document-review.stories.tsx b/ui/storybook/stories/document-review.stories.tsx
new file mode 100644
index 00000000000..f2532ebeff5
--- /dev/null
+++ b/ui/storybook/stories/document-review.stories.tsx
@@ -0,0 +1,366 @@
+import type { Meta, StoryObj } from "@storybook/react-vite";
+import { AlertTriangle, BookOpen, History, Link2, Lock, Pencil } from "lucide-react";
+import type {
+  DocumentReviewIndex,
+  DocumentSuggestionWithComments,
+} from "@paperclipai/shared";
+import { DocumentReviewRail } from "@/components/documents/DocumentReviewRail";
+import { SuggestionCard } from "@/components/documents/SuggestionCard";
+import { SelectionToolbar } from "@/components/documents/SelectionToolbar";
+import { StatusBadge } from "@/components/StatusBadge";
+import { Badge } from "@/components/ui/badge";
+import { Button } from "@/components/ui/button";
+import { MarkdownBody } from "@/components/MarkdownBody";
+
+/**
+ * Storybook coverage for the document detail / review surface (PAP-10568).
+ *
+ * Renders the real review rail, suggestion cards, and selection toolbar with
+ * fixture data so UX/QA can capture desktop screenshots for sign-off without a
+ * live backend. Behaviour is unit-tested alongside each component.
+ */
+
+const HOUR = 1000 * 60 * 60;
+const now = new Date("2026-06-07T12:00:00Z").getTime();
+
+const agentMap = new Map([
+  ["agent-claude", { id: "agent-claude", name: "ClaudeCoder" }],
+  ["agent-cto", { id: "agent-cto", name: "CTO" }],
+]);
+
+function suggestion(overrides: Partial<DocumentSuggestionWithComments>): DocumentSuggestionWithComments {
+  return {
+    id: "sug",
+    companyId: "c",
+    issueId: "i",
+    documentId: "d",
+    documentKey: "spec",
+    kind: "substitution",
+    status: "pending",
+    anchorState: "active",
+    anchorConfidence: "exact",
+    originalRevisionId: "rev-12",
+    originalRevisionNumber: 12,
+    currentRevisionId: "rev-12",
+    currentRevisionNumber: 12,
+    selectedText: "review state and suggested edits.",
+    proposedText: "review state, suggested edits, and orphan reconciliation.",
+    insertionPosition: null,
+    prefixText: "",
+    suffixText: "",
+    normalizedStart: 0,
+    normalizedEnd: 10,
+    markdownStart: 0,
+    markdownEnd: 10,
+    anchorSelector: {
+      quote: { exact: "review state and suggested edits.", prefix: "", suffix: "" },
+      position: { normalizedStart: 0, normalizedEnd: 10, markdownStart: 0, markdownEnd: 10 },
+    },
+    createdByAgentId: "agent-claude",
+    createdByUserId: null,
+    acceptedByAgentId: null,
+    acceptedByUserId: null,
+    acceptedAt: null,
+    acceptedRevisionId: null,
+    rejectedByAgentId: null,
+    rejectedByUserId: null,
+    rejectedAt: null,
+    createdAt: new Date(now - 2 * HOUR),
+    updatedAt: new Date(now - 2 * HOUR),
+    comments: [
+      {
+        id: "sc1",
+        companyId: "c",
+        suggestionId: "sug",
+        issueId: "i",
+        documentId: "d",
+        body: "Looks right. Ship.",
+        authorType: "agent",
+        authorAgentId: "agent-cto",
+        authorUserId: null,
+        createdByRunId: null,
+        createdAt: new Date(now - HOUR),
+        updatedAt: new Date(now - HOUR),
+      },
+    ],
+    ...overrides,
+  };
+}
+
+const reviewIndex: DocumentReviewIndex = {
+  issueId: "i",
+  documentId: "d",
+  documentKey: "spec",
+  latestRevisionId: "rev-12",
+  latestRevisionNumber: 12,
+  counts: {
+    unresolved: 4,
+    openAnchoredThreads: 2,
+    openReviewThreads: 1,
+    pendingSuggestions: 3,
+    resolvedAnchoredThreads: 1,
+    resolvedReviewThreads: 0,
+    acceptedSuggestions: 0,
+    rejectedSuggestions: 1,
+    staleAnchors: 1,
+    orphanedAnchors: 1,
+  },
+  annotationThreads: [
+    {
+      id: "t-open",
+      companyId: "c",
+      issueId: "i",
+      documentId: "d",
+      documentKey: "spec",
+      status: "open",
+      anchorState: "active",
+      anchorConfidence: "exact",
+      originalRevisionId: "rev-12",
+      originalRevisionNumber: 12,
+      currentRevisionId: "rev-12",
+      currentRevisionNumber: 12,
+      selectedText: "the orchestrator should never proceed",
+      prefixText: "",
+      suffixText: "",
+      normalizedStart: 0,
+      normalizedEnd: 10,
+      markdownStart: 0,
+      markdownEnd: 10,
+      anchorSelector: { quote: { exact: "the orchestrator should never proceed", prefix: "", suffix: "" }, position: { normalizedStart: 0, normalizedEnd: 10, markdownStart: 0, markdownEnd: 10 } },
+      createdByAgentId: "agent-claude",
+      createdByUserId: null,
+      resolvedByAgentId: null,
+      resolvedByUserId: null,
+      resolvedAt: null,
+      createdAt: new Date(now - 2 * HOUR),
+      updatedAt: new Date(now - 2 * HOUR),
+      comments: [
+        { id: "tc1", companyId: "c", threadId: "t-open", issueId: "i", documentId: "d", body: "Worth being more explicit here?", authorType: "agent", authorAgentId: "agent-claude", authorUserId: null, createdByRunId: null, createdAt: new Date(now - 2 * HOUR), updatedAt: new Date(now - 2 * HOUR) },
+        { id: "tc2", companyId: "c", threadId: "t-open", issueId: "i", documentId: "d", body: "Agreed. Add an example for the \"no, never proceed\" path.", authorType: "agent", authorAgentId: "agent-cto", authorUserId: null, createdByRunId: null, createdAt: new Date(now - HOUR), updatedAt: new Date(now - HOUR) },
+      ],
+    },
+    {
+      id: "t-stale",
+      companyId: "c",
+      issueId: "i",
+      documentId: "d",
+      documentKey: "spec",
+      status: "open",
+      anchorState: "stale",
+      anchorConfidence: "fuzzy",
+      originalRevisionId: "rev-11",
+      originalRevisionNumber: 11,
+      currentRevisionId: "rev-12",
+      currentRevisionNumber: 12,
+      selectedText: "anchored text that drifted",
+      prefixText: "",
+      suffixText: "",
+      normalizedStart: 0,
+      normalizedEnd: 10,
+      markdownStart: 0,
+      markdownEnd: 10,
+      anchorSelector: { quote: { exact: "anchored text that drifted", prefix: "", suffix: "" }, position: { normalizedStart: 0, normalizedEnd: 10, markdownStart: 0, markdownEnd: 10 } },
+      createdByAgentId: "agent-cto",
+      createdByUserId: null,
+      resolvedByAgentId: null,
+      resolvedByUserId: null,
+      resolvedAt: null,
+      createdAt: new Date(now - 5 * HOUR),
+      updatedAt: new Date(now - 5 * HOUR),
+      comments: [
+        { id: "tc3", companyId: "c", threadId: "t-stale", issueId: "i", documentId: "d", body: "This moved when the intro was rewritten.", authorType: "agent", authorAgentId: "agent-cto", authorUserId: null, createdByRunId: null, createdAt: new Date(now - 5 * HOUR), updatedAt: new Date(now - 5 * HOUR) },
+      ],
+    },
+    {
+      id: "t-orphan",
+      companyId: "c",
+      issueId: "i",
+      documentId: "d",
+      documentKey: "spec",
+      status: "open",
+      anchorState: "orphaned",
+      anchorConfidence: "missing",
+      originalRevisionId: "rev-9",
+      originalRevisionNumber: 9,
+      currentRevisionId: "rev-12",
+      currentRevisionNumber: 12,
+      selectedText: "a paragraph that was deleted entirely",
+      prefixText: "",
+      suffixText: "",
+      normalizedStart: 0,
+      normalizedEnd: 10,
+      markdownStart: 0,
+      markdownEnd: 10,
+      anchorSelector: { quote: { exact: "a paragraph that was deleted entirely", prefix: "", suffix: "" }, position: { normalizedStart: 0, normalizedEnd: 10, markdownStart: 0, markdownEnd: 10 } },
+      createdByAgentId: "agent-claude",
+      createdByUserId: null,
+      resolvedByAgentId: null,
+      resolvedByUserId: null,
+      resolvedAt: null,
+      createdAt: new Date(now - 8 * HOUR),
+      updatedAt: new Date(now - 8 * HOUR),
+      comments: [
+        { id: "tc4", companyId: "c", threadId: "t-orphan", issueId: "i", documentId: "d", body: "Where did this section go?", authorType: "agent", authorAgentId: "agent-claude", authorUserId: null, createdByRunId: null, createdAt: new Date(now - 8 * HOUR), updatedAt: new Date(now - 8 * HOUR) },
+      ],
+    },
+  ],
+  reviewThreads: [
+    {
+      id: "overall",
+      companyId: "c",
+      issueId: "i",
+      documentId: "d",
+      documentKey: "spec",
+      status: "open",
+      createdByAgentId: "agent-cto",
+      createdByUserId: null,
+      resolvedByAgentId: null,
+      resolvedByUserId: null,
+      resolvedAt: null,
+      createdAt: new Date(now - 3 * HOUR),
+      updatedAt: new Date(now - 3 * HOUR),
+      comments: [
+        { id: "oc1", companyId: "c", threadId: "overall", issueId: "i", documentId: "d", body: "Suggestions look right — accept the two pending edits and we can ship.", authorType: "agent", authorAgentId: "agent-cto", authorUserId: null, createdByRunId: null, createdAt: new Date(now - 3 * HOUR), updatedAt: new Date(now - 3 * HOUR) },
+      ],
+    },
+  ],
+  suggestions: [
+    suggestion({ id: "sug-replace", kind: "substitution" }),
+    suggestion({ id: "sug-insert", kind: "insertion", insertionPosition: "after", selectedText: "review flow", proposedText: "Also note the orphan-reconciliation pass.", comments: [] }),
+    suggestion({ id: "sug-delete", kind: "deletion", selectedText: "This sentence is redundant and should go.", proposedText: null, comments: [] }),
+    suggestion({ id: "sug-rebase", kind: "substitution", currentRevisionId: "rev-11", selectedText: "stale base", proposedText: "needs rebase onto rev 12", comments: [] }),
+  ],
+};
+
+const noop = () => {};
+const asyncNoop = async () => {};
+
+const railHandlers = {
+  onReplyThread: asyncNoop,
+  onToggleThreadResolved: asyncNoop,
+  onAddOverallComment: asyncNoop,
+  onAcceptSuggestion: asyncNoop,
+  onRejectSuggestion: asyncNoop,
+  onReplySuggestion: asyncNoop,
+  onViewSuggestionDiff: noop,
+};
+
+const SAMPLE_BODY = `# Paperclip Documents review flow
+
+The orchestrator should never proceed when a reviewer has left blocking
+feedback. Review state and suggested edits are tracked as discrete rows so an
+agent and a human read the same index.
+
+## Anchored feedback
+
+Highlighted spans carry comments and suggestions. When the body changes, anchors
+remap; drifted anchors are flagged **stale** and lost ones become **orphaned**.`;
+
+const meta: Meta = {
+  title: "Documents/Review",
+};
+export default meta;
+
+type Story = StoryObj;
+
+function DetailHeader() {
+  return (
+    <header className="px-4 pt-4">
+      <div className="mb-1 flex flex-wrap items-center gap-2">
+        <h1 className="text-xl font-bold text-foreground">Paperclip Documents review flow</h1>
+        <StatusBadge status="in_review" />
+        <span className="inline-flex items-center gap-1 text-xs text-muted-foreground">
+          <BookOpen className="h-3.5 w-3.5" /> Spec
+        </span>
+        <span className="text-xs text-muted-foreground">Owner: ClaudeCoder</span>
+      </div>
+      <div className="mb-2 flex flex-wrap items-center gap-1.5">
+        <Button size="sm" variant="outline" className="h-8"><Pencil className="mr-1 h-3.5 w-3.5" />Edit</Button>
+        <Button size="sm" variant="ghost" className="h-8"><Pencil className="mr-1 h-3.5 w-3.5" />Suggest edit</Button>
+        <Button size="sm" variant="ghost" className="h-8"><History className="mr-1 h-3.5 w-3.5" />History</Button>
+        <Button size="sm" variant="ghost" className="h-8"><Lock className="mr-1 h-3.5 w-3.5" />Lock</Button>
+        <Button size="sm" variant="ghost" className="h-8"><Link2 className="mr-1 h-3.5 w-3.5" />Copy link</Button>
+      </div>
+      <div className="mb-1.5 flex flex-wrap items-center gap-1.5">
+        <span className="text-[11px] text-muted-foreground">Backlinks:</span>
+        <Badge variant="outline" className="px-1.5 py-0 text-[10px] font-mono">PAP-10520</Badge>
+        <Badge variant="outline" className="px-1.5 py-0 text-[10px] font-mono">PAP-10522</Badge>
+      </div>
+      <div className="mb-3 flex items-center gap-2 border-b border-border pb-3 text-[11px] text-muted-foreground">
+        <span className="rounded border border-border px-1.5 py-0.5 font-mono">Rev 12</span>
+        <span>updated 2h ago by ClaudeCoder</span>
+      </div>
+    </header>
+  );
+}
+
+export const DetailDesktop: Story = {
+  render: () => (
+    <div className="flex h-[680px] w-full overflow-hidden rounded-md border border-border bg-background">
+      <div className="flex min-w-0 flex-1 flex-col overflow-y-auto">
+        <DetailHeader />
+        <div className="px-4 pb-8">
+          <div className="mx-auto w-full max-w-[78ch]">
+            <MarkdownBody>{SAMPLE_BODY}</MarkdownBody>
+          </div>
+        </div>
+      </div>
+      <div className="w-[360px] shrink-0">
+        <DocumentReviewRail reviewIndex={reviewIndex} canReview canFinishReview latestRevisionId="rev-12" authorMaps={{ agentMap }} {...railHandlers} />
+      </div>
+    </div>
+  ),
+};
+
+export const RailComments: Story = {
+  render: () => (
+    <div className="h-[680px] w-[360px] overflow-hidden rounded-md border border-border">
+      <DocumentReviewRail reviewIndex={reviewIndex} canReview canFinishReview latestRevisionId="rev-12" authorMaps={{ agentMap }} {...railHandlers} />
+    </div>
+  ),
+};
+
+export const RailSuggestions: Story = {
+  render: () => (
+    <div className="h-[680px] w-[360px] overflow-hidden rounded-md border border-border">
+      <DocumentReviewRail reviewIndex={reviewIndex} canReview canFinishReview latestRevisionId="rev-12" initialTab="suggestions" authorMaps={{ agentMap }} {...railHandlers} />
+    </div>
+  ),
+};
+
+export const ConflictBanner: Story = {
+  render: () => (
+    <div
+      role="alert"
+      className="m-4 flex max-w-2xl flex-wrap items-center gap-2 rounded-md border border-amber-300 bg-amber-50 px-3 py-2 text-sm text-amber-800 dark:border-amber-800 dark:bg-amber-950/40 dark:text-amber-200"
+    >
+      <AlertTriangle className="h-4 w-4 shrink-0" />
+      <span className="flex-1">Someone updated this document while you were editing.</span>
+      <Button size="sm" variant="outline" className="h-7 text-xs">View their changes</Button>
+      <Button size="sm" variant="outline" className="h-7 text-xs">Rebase my draft</Button>
+      <Button size="sm" variant="ghost" className="h-7 text-xs text-destructive hover:text-destructive">Discard mine</Button>
+    </div>
+  ),
+};
+
+export const Suggestions: Story = {
+  render: () => (
+    <div className="w-[340px] space-y-3 p-4">
+      <SuggestionCard suggestion={suggestion({ id: "s-replace", kind: "substitution" })} latestRevisionId="rev-12" canReview authorMaps={{ agentMap }} onAccept={asyncNoop} onReject={asyncNoop} onReply={asyncNoop} />
+      <SuggestionCard suggestion={suggestion({ id: "s-insert", kind: "insertion", insertionPosition: "after", selectedText: "review flow", proposedText: "Also note the orphan-reconciliation pass.", comments: [] })} latestRevisionId="rev-12" canReview authorMaps={{ agentMap }} onAccept={asyncNoop} onReject={asyncNoop} onReply={asyncNoop} />
+      <SuggestionCard suggestion={suggestion({ id: "s-delete", kind: "deletion", selectedText: "This sentence is redundant.", proposedText: null, comments: [] })} latestRevisionId="rev-12" canReview authorMaps={{ agentMap }} onAccept={asyncNoop} onReject={asyncNoop} onReply={asyncNoop} />
+      <SuggestionCard suggestion={suggestion({ id: "s-rebase", kind: "substitution", currentRevisionId: "rev-11", selectedText: "stale base", proposedText: "needs rebase", comments: [] })} latestRevisionId="rev-12" canReview authorMaps={{ agentMap }} onAccept={asyncNoop} onReject={asyncNoop} onReply={asyncNoop} />
+    </div>
+  ),
+};
+
+export const SelectionToolbarStory: Story = {
+  name: "Selection toolbar",
+  render: () => (
+    <div className="p-8">
+      <div className="inline-flex items-center gap-1 rounded-md border border-border bg-popover px-1 py-1 shadow-md">
+        <SelectionToolbar onComment={noop} onSuggest={noop} onCopyLink={noop} />
+      </div>
+    </div>
+  ),
+};