OpenKnots · BunsDev · Apr 3, 2026 · Apr 3, 2026
diff --git a/apps/server/src/prReview/Layers/PrReview.ts b/apps/server/src/prReview/Layers/PrReview.ts
@@ -259,14 +259,24 @@ function buildSyntheticPatch(file: {
   patch: string | null;
 }): string | null {
   if (!file.patch) return null;
-  const currentPath = file.path;
-  const previousPath = file.previousPath ?? file.path;
-  const oldPath = file.status === "added" ? "/dev/null" : `a/${previousPath.replaceAll("\\", "/")}`;
-  const newPath =
-    file.status === "removed" ? "/dev/null" : `b/${currentPath.replaceAll("\\", "/")}`;
-  return [`diff --git ${oldPath} ${newPath}`, `--- ${oldPath}`, `+++ ${newPath}`, file.patch].join(
-    "\n",
-  );
+  const currentPath = file.path.replaceAll("\\", "/");
+  const previousPath = (file.previousPath ?? file.path).replaceAll("\\", "/");
+
+  // The diff --git header MUST always use a/ and b/ prefixes for the parser
+  // (@pierre/diffs ALTERNATE_FILE_NAMES_GIT regex requires this format).
+  // /dev/null is only valid in the --- and +++ lines.
+  const gitHeaderA = `a/${previousPath}`;
+  const gitHeaderB = `b/${currentPath}`;
+
+  const headerOld = file.status === "added" ? "/dev/null" : `a/${previousPath}`;
+  const headerNew = file.status === "removed" ? "/dev/null" : `b/${currentPath}`;
+
+  const lines = [`diff --git ${gitHeaderA} ${gitHeaderB}`];
+  if (file.status === "added") lines.push("new file mode 100644");
+  if (file.status === "removed") lines.push("deleted file mode 100644");
+  lines.push(`--- ${headerOld}`, `+++ ${headerNew}`, file.patch);
+
+  return lines.join("\n");
 }
 
 function normalizeStatusChecks(raw: unknown): PrReviewSummary["statusChecks"] {

diff --git a/apps/web/src/components/pr-review/PrFileTabStrip.tsx b/apps/web/src/components/pr-review/PrFileTabStrip.tsx
@@ -1,7 +1,7 @@
 import type { FileDiffMetadata } from "@pierre/diffs/react";
 import type { PrReviewThread } from "@okcode/contracts";
 import { useMemo, useRef, useEffect } from "react";
-import { ListIcon, FileIcon } from "lucide-react";
+import { CheckCircle2Icon, ListIcon, FileIcon } from "lucide-react";
 import { cn } from "~/lib/utils";
 import { Button } from "~/components/ui/button";
 import { resolveFileDiffPath, summarizeFileDiffStats } from "./pr-review-utils";
@@ -17,13 +17,15 @@ export function PrFileTabStrip({
   files,
   threads,
   selectedFilePath,
+  reviewedFiles,
   onSelectFilePath,
   fileViewMode,
   onFileViewModeChange,
 }: {
   files: FileDiffMetadata[];
   threads: readonly PrReviewThread[];
   selectedFilePath: string | null;
+  reviewedFiles: ReadonlySet<string>;
   onSelectFilePath: (path: string) => void;
   fileViewMode: FileViewMode;
   onFileViewModeChange: (mode: FileViewMode) => void;
@@ -52,9 +54,10 @@ export function PrFileTabStrip({
           additions: stats.additions,
           deletions: stats.deletions,
           threadCount: threadsByPath[path] ?? 0,
+          reviewed: reviewedFiles.has(path),
         };
       }),
-    [files, threadsByPath],
+    [files, threadsByPath, reviewedFiles],
   );
 
   // Scroll the active tab into view when it changes
@@ -88,11 +91,17 @@ export function PrFileTabStrip({
                 "group relative flex shrink-0 items-center gap-1.5 rounded-md px-2.5 py-1.5 text-xs font-medium transition-colors",
                 isActive
                   ? "bg-amber-500/10 text-amber-700 dark:text-amber-300"
-                  : "text-muted-foreground hover:bg-muted/50 hover:text-foreground",
+                  : entry.reviewed
+                    ? "text-emerald-600/70 dark:text-emerald-400/70 hover:bg-muted/50 hover:text-foreground"
+                    : "text-muted-foreground hover:bg-muted/50 hover:text-foreground",
               )}
               type="button"
             >
-              <FileIcon className="size-3 shrink-0 opacity-60" />
+              {entry.reviewed ? (
+                <CheckCircle2Icon className="size-3 shrink-0 text-emerald-500" />
+              ) : (
+                <FileIcon className="size-3 shrink-0 opacity-60" />
+              )}
               <span className="truncate max-w-[120px]">{entry.basename}</span>
               <span
                 className={cn(

diff --git a/apps/web/src/components/pr-review/PrReviewShell.tsx b/apps/web/src/components/pr-review/PrReviewShell.tsx
@@ -44,6 +44,7 @@ import { PrInspectorPanel } from "./PrInspectorPanel";
 import { PrMentionComposer } from "./PrMentionComposer";
 import {
   type PullRequestState,
+  REVIEWED_FILES_SCHEMA,
   TEXT_DRAFT_SCHEMA,
   requiredChecksState,
   openPathInEditor,
@@ -76,6 +77,12 @@ export function PrReviewShell({
   const deferredSearchQuery = useDeferredValue(searchQuery);
   const reviewDraftKey = `okcode:pr-review:review-draft:${project.id}:${selectedPrNumber ?? "none"}`;
   const [reviewBody, setReviewBody] = useLocalStorage(reviewDraftKey, "", TEXT_DRAFT_SCHEMA);
+  const reviewedFilesKey = `okcode:pr-review:reviewed-files:${project.id}:${selectedPrNumber ?? "none"}`;
+  const [reviewedFiles, setReviewedFiles] = useLocalStorage<readonly string[], unknown>(
+    reviewedFilesKey,
+    [],
+    REVIEWED_FILES_SCHEMA,
+  );
 
   // --- Collapsible panel state ---
   const [leftRailCollapsed, setLeftRailCollapsed] = useLocalStorage(
@@ -382,7 +389,7 @@ export function PrReviewShell({
   return (
     <>
       {/* Main content area — flexbox layout with collapsible panels */}
-      <div className="flex min-h-0 flex-1 overflow-x-hidden overflow-y-auto">
+      <div className="flex min-h-0 flex-1 overflow-hidden">
         {/* Left rail — collapsible */}
         <PrListRail
           collapsed={leftRailCollapsed}
@@ -430,8 +437,17 @@ export function PrReviewShell({
                 setInspectorCollapsed(false);
               }
             }}
+            onToggleFileReviewed={(path) => {
+              setReviewedFiles((prev) => {
+                const set = new Set(prev);
+                if (set.has(path)) set.delete(path);
+                else set.add(path);
+                return [...set];
+              });
+            }}
             patch={patchQuery.data?.combinedPatch ?? null}
             project={project}
+            reviewedFiles={reviewedFiles}
             selectedFilePath={selectedFilePath}
             selectedThreadId={selectedThreadId}
           />

diff --git a/apps/web/src/components/pr-review/PrWorkspace.tsx b/apps/web/src/components/pr-review/PrWorkspace.tsx
@@ -3,7 +3,9 @@ import type { NativeApi, PrReviewThread } from "@okcode/contracts";
 import { useMemo } from "react";
 import { Schema } from "effect";
 import {
+  CheckCircle2Icon,
   ChevronRightIcon,
+  CircleIcon,
   ExternalLinkIcon,
   FileCode2Icon,
   GitBranchIcon,
@@ -38,18 +40,22 @@ export function PrWorkspace({
   dashboard,
   selectedFilePath,
   selectedThreadId,
+  reviewedFiles,
   onSelectFilePath,
   onSelectThreadId,
   onCreateThread,
+  onToggleFileReviewed,
 }: {
   project: Project;
   patch: string | null;
   dashboard: Awaited<ReturnType<NativeApi["prReview"]["getDashboard"]>> | null | undefined;
   selectedFilePath: string | null;
   selectedThreadId: string | null;
+  reviewedFiles: readonly string[];
   onSelectFilePath: (path: string) => void;
   onSelectThreadId: (threadId: string | null) => void;
   onCreateThread: (input: { path: string; line: number; body: string }) => Promise<void>;
+  onToggleFileReviewed: (path: string) => void;
 }) {
   const { resolvedTheme } = useTheme();
   const openFileInCodeViewer = useFileViewNavigation();
@@ -59,6 +65,8 @@ export function PrWorkspace({
     FILE_VIEW_MODE_SCHEMA,
   );
 
+  const reviewedFilesSet = useMemo(() => new Set(reviewedFiles), [reviewedFiles]);
+
   const renderablePatch = useMemo(
     () =>
       parseRenderablePatch(
@@ -123,6 +131,31 @@ export function PrWorkspace({
             <FileCode2Icon className="size-3" />
             {dashboard.files.length}
           </span>
+          {patchFiles.length > 0
+            ? (() => {
+                const reviewedCount = patchFiles.filter((f) =>
+                  reviewedFilesSet.has(resolveFileDiffPath(f)),
+                ).length;
+                return (
+                  <>
+                    <span className="hidden shrink-0 text-muted-foreground/50 sm:inline">
+                      &middot;
+                    </span>
+                    <span
+                      className={cn(
+                        "hidden shrink-0 items-center gap-1.5 text-xs font-medium sm:flex",
+                        reviewedCount >= patchFiles.length
+                          ? "text-emerald-600 dark:text-emerald-400"
+                          : "text-muted-foreground",
+                      )}
+                    >
+                      <CheckCircle2Icon className="size-3" />
+                      {reviewedCount}/{patchFiles.length} viewed
+                    </span>
+                  </>
+                );
+              })()
+            : null}
         </div>
         <Button
           onClick={() => {
@@ -142,6 +175,7 @@ export function PrWorkspace({
           files={patchFiles}
           threads={dashboard.threads}
           selectedFilePath={selectedFilePath}
+          reviewedFiles={reviewedFilesSet}
           onSelectFilePath={(path) => {
             onSelectFilePath(path);
             // In all-files mode, scroll to the file
@@ -171,6 +205,7 @@ export function PrWorkspace({
             const fileKey = `${buildFileDiffRenderKey(fileDiff)}:${resolvedTheme}`;
             const fileThreads = threadsByPath[filePath] ?? [];
             const isSelected = selectedFilePath === filePath;
+            const isReviewed = reviewedFilesSet.has(filePath);
             const firstCommentLine = fileThreads[0]?.line ?? 1;
             const stats = summarizeFileDiffStats(fileDiff);
             return (
@@ -219,6 +254,27 @@ export function PrWorkspace({
                         +{fileThreads.length - 2} more
                       </span>
                     ) : null}
+                    <button
+                      className={cn(
+                        "inline-flex items-center gap-1 rounded-full border px-2.5 py-0.5 text-[11px] font-medium transition-colors",
+                        isReviewed
+                          ? "border-emerald-500/20 bg-emerald-500/8 text-emerald-600 dark:text-emerald-300"
+                          : "border-border/70 bg-background text-muted-foreground hover:bg-muted/40",
+                      )}
+                      onClick={(e) => {
+                        e.stopPropagation();
+                        onToggleFileReviewed(filePath);
+                      }}
+                      type="button"
+                      title={isReviewed ? "Mark as unreviewed" : "Mark as reviewed"}
+                    >
+                      {isReviewed ? (
+                        <CheckCircle2Icon className="size-3" />
+                      ) : (
+                        <CircleIcon className="size-3" />
+                      )}
+                      Viewed
+                    </button>
                     <Button
                       onClick={() => {
                         openFileInCodeViewer(project.cwd, filePath);

diff --git a/apps/web/src/components/pr-review/pr-review-utils.tsx b/apps/web/src/components/pr-review/pr-review-utils.tsx
@@ -21,6 +21,7 @@ export type RenderablePatch =
   | { kind: "raw"; text: string; reason: string };
 
 export const TEXT_DRAFT_SCHEMA = Schema.String;
+export const REVIEWED_FILES_SCHEMA = Schema.Array(Schema.String);
 
 export const PR_REVIEW_DIFF_UNSAFE_CSS = `
 [data-diff],