diff --git a/packages/vscode-ide-companion/src/diff-manager.ts b/packages/vscode-ide-companion/src/diff-manager.ts
index 4f151870..cca203ea 100644
--- a/packages/vscode-ide-companion/src/diff-manager.ts
+++ b/packages/vscode-ide-companion/src/diff-manager.ts
@@ -12,6 +12,10 @@ import { type JSONRPCNotification } from '@modelcontextprotocol/sdk/types.js';
 import * as path from 'node:path';
 import * as vscode from 'vscode';
 import { DIFF_SCHEME } from './extension.js';
+import {
+  findLeftGroupOfChatWebview,
+  ensureLeftGroupOfChatWebview,
+} from './utils/editorGroupUtils.js';
 
 export class DiffContentProvider implements vscode.TextDocumentContentProvider {
   private content = new Map<string, string>();
@@ -110,13 +114,28 @@ export class DiffManager {
       true,
     );
 
+    // Prefer opening the diff adjacent to the chat webview (so we don't
+    // replace content inside the locked webview group). We try the group to
+    // the left of the chat webview first; if none exists we fall back to
+    // ViewColumn.Beside. With the chat locked in the leftmost group, this
+    // fallback opens diffs to the right of the chat.
+    let targetViewColumn = findLeftGroupOfChatWebview();
+    if (targetViewColumn === undefined) {
+      // If there is no left neighbor, create one to satisfy the requirement of
+      // opening diffs to the left of the chat webview.
+      targetViewColumn = await ensureLeftGroupOfChatWebview();
+    }
+
     await vscode.commands.executeCommand(
       'vscode.diff',
       leftDocUri,
       rightDocUri,
       diffTitle,
       {
-        viewColumn: vscode.ViewColumn.Beside,
+        // If a left-of-webview group was found, target it explicitly so the
+        // diff opens there while keeping focus on the webview. Otherwise, use
+        // the default "open to side" behavior.
+        viewColumn: targetViewColumn ?? vscode.ViewColumn.Beside,
         preview: false,
         preserveFocus: true,
       },
diff --git a/packages/vscode-ide-companion/src/utils/editorGroupUtils.ts b/packages/vscode-ide-companion/src/utils/editorGroupUtils.ts
new file mode 100644
index 00000000..c4827b35
--- /dev/null
+++ b/packages/vscode-ide-companion/src/utils/editorGroupUtils.ts
@@ -0,0 +1,115 @@
+/**
+ * @license
+ * Copyright 2025 Qwen Team
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import * as vscode from 'vscode';
+
+/**
+ * Find the editor group immediately to the left of the Qwen chat webview.
+ * - If the chat webview group is the leftmost group, returns undefined.
+ * - Uses the webview tab viewType 'mainThreadWebview-qwenCode.chat'.
+ */
+export function findLeftGroupOfChatWebview(): vscode.ViewColumn | undefined {
+  try {
+    const groups = vscode.window.tabGroups.all;
+
+    // Locate the group that contains our chat webview
+    const webviewGroup = groups.find((group) =>
+      group.tabs.some((tab) => {
+        const input: unknown = (tab as { input?: unknown }).input;
+        const isWebviewInput = (inp: unknown): inp is { viewType: string } =>
+          !!inp && typeof inp === 'object' && 'viewType' in inp;
+        return (
+          isWebviewInput(input) &&
+          input.viewType === 'mainThreadWebview-qwenCode.chat'
+        );
+      }),
+    );
+
+    if (!webviewGroup) {
+      return undefined;
+    }
+
+    // Among all groups to the left (smaller viewColumn), choose the one with
+    // the largest viewColumn value (i.e. the immediate neighbor on the left).
+    let candidate:
+      | { group: vscode.TabGroup; viewColumn: vscode.ViewColumn }
+      | undefined;
+    for (const g of groups) {
+      if (g.viewColumn < webviewGroup.viewColumn) {
+        if (!candidate || g.viewColumn > candidate.viewColumn) {
+          candidate = { group: g, viewColumn: g.viewColumn };
+        }
+      }
+    }
+
+    return candidate?.viewColumn;
+  } catch (_err) {
+    // Best-effort only; fall back to default behavior if anything goes wrong
+    return undefined;
+  }
+}
+
+/**
+ * Ensure there is an editor group directly to the left of the Qwen chat webview.
+ * - If one exists, return its ViewColumn.
+ * - If none exists, focus the chat panel and create a new group on its left,
+ *   then return the new group's ViewColumn (which equals the chat's previous column).
+ * - If the chat webview cannot be located, returns undefined.
+ */
+export async function ensureLeftGroupOfChatWebview(): Promise<
+  vscode.ViewColumn | undefined
+> {
+  // First try to find an existing left neighbor
+  const existing = findLeftGroupOfChatWebview();
+  if (existing !== undefined) {
+    return existing;
+  }
+
+  // Locate the chat webview group
+  const groups = vscode.window.tabGroups.all;
+  const webviewGroup = groups.find((group) =>
+    group.tabs.some((tab) => {
+      const input: unknown = (tab as { input?: unknown }).input;
+      const isWebviewInput = (inp: unknown): inp is { viewType: string } =>
+        !!inp && typeof inp === 'object' && 'viewType' in inp;
+      return (
+        isWebviewInput(input) &&
+        input.viewType === 'mainThreadWebview-qwenCode.chat'
+      );
+    }),
+  );
+
+  if (!webviewGroup) {
+    return undefined;
+  }
+
+  const previousChatColumn = webviewGroup.viewColumn;
+
+  // Make the chat group active by revealing the panel
+  try {
+    await vscode.commands.executeCommand('qwenCode.openChat');
+  } catch {
+    // Best-effort; continue even if this fails
+  }
+
+  // Create a new group to the left of the chat group
+  try {
+    await vscode.commands.executeCommand('workbench.action.newGroupLeft');
+  } catch {
+    // If we fail to create a group, fall back to default behavior
+    return undefined;
+  }
+
+  // Restore focus to chat (optional), so we don't disturb user focus
+  try {
+    await vscode.commands.executeCommand('qwenCode.openChat');
+  } catch {
+    // Ignore
+  }
+
+  // The new left group's column equals the chat's previous column
+  return previousChatColumn;
+}