feat: add Apply Patch tool with patch input and diff view (#196)

* feat: add Apply Patch tool with patch input and diff view

Introduce Apply Patch tool with a patch input field and diff preview
Display target file path or file count for patch operations in tool UI
Update status label to show applying patch during execution

* fix: include apply_patch in editing tools detection

packages/ui/src/components/chat/message/MessageBody.tsx

@@ -283,6 +283,7 @@ const AssistantMessageBody: React.FC<Omit<MessageBodyProps, 'isUser'>> = ({
     errorMessage,
 }) => {
 
+    void _streamPhase;
     void _allowAnimation;
     const [copyHintVisible, setCopyHintVisible] = React.useState(false);
     const copyHintTimeoutRef = React.useRef<number | null>(null);

packages/ui/src/components/chat/message/ToolOutputDialog.tsx

@@ -39,7 +39,7 @@ const getToolIcon = (toolName: string) => {
     if (tool === 'image-preview') {
         return <RiFileImageLine className={iconClass} />;
     }
-    if (tool === 'edit' || tool === 'multiedit' || tool === 'str_replace' || tool === 'str_replace_based_edit_tool') {
+    if (tool === 'edit' || tool === 'multiedit' || tool === 'apply_patch' || tool === 'str_replace' || tool === 'str_replace_based_edit_tool') {
         return <RiPencilAiLine className={iconClass} />;
     }
     if (tool === 'write' || tool === 'create' || tool === 'file_write') {
@@ -109,7 +109,8 @@ const ToolOutputDialog: React.FC<ToolOutputDialogProps> = ({ popup, onOpenChange
                         {popup.metadata?.input && typeof popup.metadata.input === 'object' &&
                             Object.keys(popup.metadata.input).length > 0 &&
                             popup.metadata?.tool !== 'todowrite' &&
-                            popup.metadata?.tool !== 'todoread' ? (() => {
+                            popup.metadata?.tool !== 'todoread' &&
+                            popup.metadata?.tool !== 'apply_patch' ? (() => {
                                 const meta = popup.metadata!;
                                 const input = meta.input as Record<string, unknown>;
 

packages/ui/src/components/chat/message/parts/ToolPart.tsx

@@ -43,7 +43,7 @@ export const getToolIcon = (toolName: string) => {
     const iconClass = 'h-3.5 w-3.5 flex-shrink-0';
     const tool = toolName.toLowerCase();
 
-    if (tool === 'edit' || tool === 'multiedit' || tool === 'str_replace' || tool === 'str_replace_based_edit_tool') {
+    if (tool === 'edit' || tool === 'multiedit' || tool === 'apply_patch' || tool === 'str_replace' || tool === 'str_replace_based_edit_tool') {
         return <RiPencilLine className={iconClass} />;
     }
     if (tool === 'write' || tool === 'create' || tool === 'file_write') {
@@ -175,6 +175,19 @@ const getToolDescription = (part: ToolPartType, state: ToolStateUnion, isMobile:
     const metadata = stateWithData.metadata;
     const input = stateWithData.input;
 
+    if (part.tool === 'apply_patch') {
+        const files = Array.isArray(metadata?.files) ? metadata?.files : [];
+        const firstFile = files[0] as { relativePath?: string; filePath?: string } | undefined;
+        const filePath = firstFile?.relativePath || firstFile?.filePath;
+        if (files.length > 1) {
+            return `${files.length} files`;
+        }
+        if (typeof filePath === 'string') {
+            return getRelativePath(filePath, currentDirectory, isMobile);
+        }
+        return 'Patch';
+    }
+
     // Question tool: show "Asked N question(s)"
     if (part.tool === 'question' && input?.questions && Array.isArray(input.questions)) {
         const count = input.questions.length;
@@ -605,7 +618,7 @@ const ToolExpandedContent: React.FC<ToolExpandedContentProps> = ({
 
         return formatInputForDisplay(input, part.tool);
     }, [input, part.tool]);
-    const hasInputText = inputTextContent.trim().length > 0;
+    const hasInputText = part.tool !== 'apply_patch' && inputTextContent.trim().length > 0;
 
     const renderScrollableBlock = (
         content: React.ReactNode,
@@ -755,7 +768,7 @@ const ToolExpandedContent: React.FC<ToolExpandedContentProps> = ({
             );
         }
 
-        if ((part.tool === 'edit' || part.tool === 'multiedit') && diffContent) {
+        if ((part.tool === 'edit' || part.tool === 'multiedit' || part.tool === 'apply_patch') && diffContent) {
             return renderScrollableBlock(
                 <DiffPreview diff={diffContent} syntaxTheme={syntaxTheme} input={input} />,
                 { className: 'p-1' }
@@ -1013,7 +1026,7 @@ const ToolPart: React.FC<ToolPartProps> = ({ part, isExpanded, onToggle, syntaxT
         onContentChange?.('structural');
     }, [isTaskTool, onContentChange, taskSummaryEntries.length]);
 
-    const diffStats = (part.tool === 'edit' || part.tool === 'multiedit') ? parseDiffStats(metadata) : null;
+    const diffStats = (part.tool === 'edit' || part.tool === 'multiedit' || part.tool === 'apply_patch') ? parseDiffStats(metadata) : null;
     const description = getToolDescription(part, state, isMobile, currentDirectory);
     const displayName = getToolMetadata(part.tool).displayName;
 

packages/ui/src/components/chat/message/toolRenderers.tsx

@@ -410,19 +410,22 @@ export const parseDiffToUnified = (diffText: string): UnifiedDiffHunk[] => {
             const newStart = match ? parseInt(match[2]) : 0;
 
             const unifiedLines: UnifiedDiffLine[] = [];
-            let lineNum = newStart;
+            let oldLineNum = oldStart;
+            let newLineNum = newStart;
             let j = i + 1;
 
             while (j < lines.length && !lines[j].startsWith('@@') && !lines[j].startsWith('Index:')) {
                 const contentLine = lines[j];
                 if (contentLine.startsWith('+')) {
-                    unifiedLines.push({ type: 'added', lineNumber: lineNum, content: contentLine.substring(1) });
+                    unifiedLines.push({ type: 'added', lineNumber: newLineNum, content: contentLine.substring(1) });
-                    lineNum++;
+                    newLineNum++;
                 } else if (contentLine.startsWith('-')) {
-                    unifiedLines.push({ type: 'removed', lineNumber: null, content: contentLine.substring(1) });
+                    unifiedLines.push({ type: 'removed', lineNumber: oldLineNum, content: contentLine.substring(1) });
+                    oldLineNum++;
                 } else if (contentLine.startsWith(' ')) {
-                    unifiedLines.push({ type: 'context', lineNumber: lineNum, content: contentLine.substring(1) });
+                    unifiedLines.push({ type: 'context', lineNumber: newLineNum, content: contentLine.substring(1) });
-                    lineNum++;
+                    oldLineNum++;
+                    newLineNum++;
                 }
                 j++;
             }

packages/ui/src/hooks/useAssistantStatus.ts

@@ -169,7 +169,7 @@ export function useAssistantStatus(): AssistantStatusSnapshot {
         let activePartType: 'text' | 'tool' | 'reasoning' | 'editing' | undefined = undefined;
         let activeToolName: string | undefined = undefined;
 
-        const editingTools = new Set(['edit', 'write']);
+        const editingTools = new Set(['edit', 'write', 'apply_patch']);
 
         for (let i = (lastAssistant.parts ?? []).length - 1; i >= 0; i -= 1) {
             const part = lastAssistant.parts?.[i];
@@ -218,6 +218,7 @@ export function useAssistantStatus(): AssistantStatusSnapshot {
             write: 'writing file',
             edit: 'editing file',
             multiedit: 'editing files',
+            apply_patch: 'applying patch',
             bash: 'running command',
             grep: 'searching content',
             glob: 'finding files',

packages/ui/src/lib/toolHelpers.ts

@@ -52,6 +52,14 @@ export const TOOL_METADATA: Record<string, ToolMetadata> = {
       { key: 'edits', label: 'Edits', type: 'code', language: 'json' }
     ]
   },
+  apply_patch: {
+    displayName: 'Apply Patch',
+    category: 'file',
+    outputLanguage: 'diff',
+    inputFields: [
+      { key: 'patchText', label: 'Patch', type: 'code', language: 'diff' }
+    ]
+  },
 
   bash: {
     displayName: 'Shell Command',
@@ -665,6 +673,13 @@ export function formatToolInput(input: Record<string, unknown>, toolName: string
     if (desc) return desc;
   }
 
+  if (toolName === 'apply_patch' && typeof input === 'object') {
+    const patchText = getString('patchText') || getString('patch_text') || getString('patch');
+    if (patchText) {
+      return patchText;
+    }
+  }
+
   if ((toolName === 'edit' || toolName === 'multiedit') && typeof input === 'object') {
     const filePath = getString('filePath') || getString('file_path') || getString('path');
     if (filePath) {