diff --git a/static/src/components/chat/actions/ToolAction.vue b/static/src/components/chat/actions/ToolAction.vue
index 0c86a32..2a12b3b 100644
--- a/static/src/components/chat/actions/ToolAction.vue
+++ b/static/src/components/chat/actions/ToolAction.vue
@@ -306,8 +306,8 @@ function renderWriteFile(result: any, args: any): string {
   if (result.success && content) {
     html += '<div class="tool-result-diff scrollable">';
     const lines = content.split('\n');
-    lines.forEach((line: string) => {
-      html += `<div class="diff-line diff-add">+ ${escapeHtml(line)}</div>`;
+    lines.forEach((line: string, idx: number) => {
+      html += `<div class="diff-line diff-add"><span class="diff-line-number">${idx + 1}</span><span class="diff-marker">+</span><span class="diff-content">${escapeHtml(line)}</span></div>`;
     });
     html += '</div>';
   }
diff --git a/static/src/components/chat/actions/toolRenderers.ts b/static/src/components/chat/actions/toolRenderers.ts
index 9a21dbb..9f374ce 100644
--- a/static/src/components/chat/actions/toolRenderers.ts
+++ b/static/src/components/chat/actions/toolRenderers.ts
@@ -246,8 +246,8 @@ function renderWriteFile(result: any, args: any): string {
   if (result.success && content) {
     html += '<div class="tool-result-diff scrollable">';
     const lines = content.split('\n');
-    lines.forEach((line: string) => {
-      html += `<div class="diff-line diff-add">+ ${escapeHtml(line)}</div>`;
+    lines.forEach((line: string, idx: number) => {
+      html += `<div class="diff-line diff-add"><span class="diff-line-number">${idx + 1}</span><span class="diff-marker">+</span><span class="diff-content">${escapeHtml(line)}</span></div>`;
     });
     html += '</div>';
   }