diff --git a/ui/src/components/ChatInterface.tsx b/ui/src/components/ChatInterface.tsx
index f2b5c1d9b1ae602eeb165c332376e27b42971877..30ba8375787b9080d04b0e144fd5a0aeef85a8d2 100644
--- a/ui/src/components/ChatInterface.tsx
+++ b/ui/src/components/ChatInterface.tsx
@@ -591,6 +591,7 @@ function ChatInterface({
   const [diffViewerInitialCommit, setDiffViewerInitialCommit] = useState<string | undefined>(
     undefined,
   );
+  const [diffViewerCwd, setDiffViewerCwd] = useState<string | undefined>(undefined);
   const [diffCommentText, setDiffCommentText] = useState("");
   const [agentWorking, setAgentWorking] = useState(false);
   const [cancelling, setCancelling] = useState(false);
@@ -1350,8 +1351,9 @@ function ChatInterface({
           <MessageComponent
             key={item.message.message_id}
             message={item.message}
-            onOpenDiffViewer={(commit) => {
+            onOpenDiffViewer={(commit, cwd) => {
               setDiffViewerInitialCommit(commit);
+              setDiffViewerCwd(cwd);
               setShowDiffViewer(true);
             }}
             onCommentTextChange={setDiffCommentText}
@@ -1825,14 +1827,16 @@ function ChatInterface({
 
       {/* Diff Viewer */}
       <DiffViewer
-        cwd={currentConversation?.cwd || selectedCwd}
+        cwd={diffViewerCwd || currentConversation?.cwd || selectedCwd}
         isOpen={showDiffViewer}
         onClose={() => {
           setShowDiffViewer(false);
           setDiffViewerInitialCommit(undefined);
+          setDiffViewerCwd(undefined);
         }}
         onCommentTextChange={setDiffCommentText}
         initialCommit={diffViewerInitialCommit}
+        onCwdChange={setDiffViewerCwd}
       />
 
       {/* Version Checker Modal */}
diff --git a/ui/src/components/DiffViewer.tsx b/ui/src/components/DiffViewer.tsx
index 357705b92717be84b9e1f93a121b4b6068ebdd4e..5b9f91db6b42af6aa8b00aaf90ce8067282c244d 100644
--- a/ui/src/components/DiffViewer.tsx
+++ b/ui/src/components/DiffViewer.tsx
@@ -3,6 +3,7 @@ import type * as Monaco from "monaco-editor";
 import { api } from "../services/api";
 import { isDarkModeActive } from "../services/theme";
 import { GitDiffInfo, GitFileInfo, GitFileDiff } from "../types";
+import DirectoryPickerModal from "./DirectoryPickerModal";
 
 interface DiffViewerProps {
   cwd: string;
@@ -10,6 +11,7 @@ interface DiffViewerProps {
   onClose: () => void;
   onCommentTextChange: (text: string) => void;
   initialCommit?: string; // If set, select this commit when opening
+  onCwdChange?: (cwd: string) => void; // Called when user picks a different git directory
 }
 
 // Icon components for cleaner JSX
@@ -79,9 +81,17 @@ function loadMonaco(): Promise<typeof Monaco> {
 
 type ViewMode = "comment" | "edit";
 
-function DiffViewer({ cwd, isOpen, onClose, onCommentTextChange, initialCommit }: DiffViewerProps) {
+function DiffViewer({
+  cwd,
+  isOpen,
+  onClose,
+  onCommentTextChange,
+  initialCommit,
+  onCwdChange,
+}: DiffViewerProps) {
   const [diffs, setDiffs] = useState<GitDiffInfo[]>([]);
   const [gitRoot, setGitRoot] = useState<string | null>(null);
+  const [showDirPicker, setShowDirPicker] = useState(false);
   const [selectedDiff, setSelectedDiff] = useState<string | null>(null);
   const [files, setFiles] = useState<GitFileInfo[]>([]);
   const [selectedFile, setSelectedFile] = useState<string | null>(null);
@@ -904,6 +914,27 @@ function DiffViewer({ cwd, isOpen, onClose, onCommentTextChange, initialCommit }
     </div>
   );
 
+  const dirButton = (
+    <button
+      className="diff-viewer-dir-btn"
+      onClick={() => setShowDirPicker(true)}
+      title={`Git directory: ${cwd}\nClick to change`}
+    >
+      <svg
+        width="16"
+        height="16"
+        viewBox="0 0 24 24"
+        fill="none"
+        stroke="currentColor"
+        strokeWidth="2"
+        strokeLinecap="round"
+        strokeLinejoin="round"
+      >
+        <path d="M22 19a2 2 0 0 1-2 2H4a2 2 0 0 1-2-2V5a2 2 0 0 1 2-2h5l2 3h9a2 2 0 0 1 2 2z" />
+      </svg>
+    </button>
+  );
+
   return (
     <div className="diff-viewer-overlay">
       <div className="diff-viewer-container">
@@ -929,6 +960,7 @@ function DiffViewer({ cwd, isOpen, onClose, onCommentTextChange, initialCommit }
               {commitSelector}
               {fileSelector}
             </div>
+            {dirButton}
             <button className="diff-viewer-close" onClick={onClose} title="Close (Esc)">
               ×
             </button>
@@ -944,6 +976,7 @@ function DiffViewer({ cwd, isOpen, onClose, onCommentTextChange, initialCommit }
               <div className="diff-viewer-controls-row">
                 {navButtons}
                 {modeToggle}
+                {dirButton}
                 <button className="diff-viewer-close" onClick={onClose} title="Close (Esc)">
                   ×
                 </button>
@@ -1072,6 +1105,18 @@ function DiffViewer({ cwd, isOpen, onClose, onCommentTextChange, initialCommit }
           </div>
         )}
       </div>
+
+      {/* Directory picker for changing git directory */}
+      <DirectoryPickerModal
+        isOpen={showDirPicker}
+        onClose={() => setShowDirPicker(false)}
+        onSelect={(path) => {
+          onCwdChange?.(path);
+          setShowDirPicker(false);
+        }}
+        initialPath={cwd}
+        foldersOnly
+      />
     </div>
   );
 }
diff --git a/ui/src/components/DirectoryPickerModal.tsx b/ui/src/components/DirectoryPickerModal.tsx
index eb6210c70939d1ad340386370beacc4c43c1cbd4..1e255e3cc4c9f7e6a611d54c78a7b62a16fb4fcb 100644
--- a/ui/src/components/DirectoryPickerModal.tsx
+++ b/ui/src/components/DirectoryPickerModal.tsx
@@ -20,6 +20,7 @@ interface DirectoryPickerModalProps {
   onClose: () => void;
   onSelect: (path: string) => void;
   initialPath?: string;
+  foldersOnly?: boolean; // If true, only show directories (hide files)
 }
 
 function DirectoryPickerModal({
@@ -27,6 +28,7 @@ function DirectoryPickerModal({
   onClose,
   onSelect,
   initialPath,
+  foldersOnly,
 }: DirectoryPickerModalProps) {
   const [inputPath, setInputPath] = useState(() => {
     if (!initialPath) return "";
@@ -173,6 +175,7 @@ function DirectoryPickerModal({
   // Filter entries based on prefix (case-insensitive)
   const filteredEntries =
     displayDir?.entries.filter((entry) => {
+      if (foldersOnly && !entry.is_dir) return false;
       if (!filterPrefix) return true;
       return entry.name.toLowerCase().startsWith(filterPrefix.toLowerCase());
     }) || [];
diff --git a/ui/src/components/Message.tsx b/ui/src/components/Message.tsx
index 08c359852b5d50db8192b5fe5a1955ac0ac7de45..c5038c0c7a98bd8cf24b6cffd617f61b308d53a3 100644
--- a/ui/src/components/Message.tsx
+++ b/ui/src/components/Message.tsx
@@ -28,7 +28,7 @@ interface ToolDisplay {
 
 interface MessageProps {
   message: MessageType;
-  onOpenDiffViewer?: (commit: string) => void;
+  onOpenDiffViewer?: (commit: string, cwd?: string) => void;
   onCommentTextChange?: (text: string) => void;
 }
 
@@ -72,7 +72,7 @@ function GitInfoMessage({
   onOpenDiffViewer,
 }: {
   message: MessageType;
-  onOpenDiffViewer?: (commit: string) => void;
+  onOpenDiffViewer?: (commit: string, cwd?: string) => void;
 }) {
   const [copied, setCopied] = useState(false);
 
@@ -111,7 +111,7 @@ function GitInfoMessage({
 
   const handleDiffClick = () => {
     if (commitHash && onOpenDiffViewer) {
-      onOpenDiffViewer(commitHash);
+      onOpenDiffViewer(commitHash, worktree || undefined);
     }
   };
 
diff --git a/ui/src/styles.css b/ui/src/styles.css
index dfa8106c5949f17122e397e9ba30488dc6f47baf..ede174c8fd18d51e4563daf0f9c49d64651043a5 100644
--- a/ui/src/styles.css
+++ b/ui/src/styles.css
@@ -3502,6 +3502,26 @@ svg {
   font-size: 0.875rem;
 }
 
+.diff-viewer-dir-btn {
+  width: 2rem;
+  height: 2rem;
+  border: none;
+  background: transparent;
+  color: var(--text-secondary);
+  cursor: pointer;
+  border-radius: 0.25rem;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  flex-shrink: 0;
+  padding: 0;
+}
+
+.diff-viewer-dir-btn:hover {
+  background: var(--bg-tertiary);
+  color: var(--text-primary);
+}
+
 .diff-viewer-close {
   width: 2rem;
   height: 2rem;