fix: writing mode uses chat search then pipeline write only

Keep deep_research_report as a write-only deliverable from conversation materials, block post-success rewrite loops with a summary nudge, fill thin/empty pools from model knowledge, and open the sandbox only on real report.md content.

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend-web/src/components/workspace/chats/chat-box.tsx

@@ -19,6 +19,7 @@ import {
   mergeArtifactPaths,
 } from "@/core/artifacts/listing";
 import { latestInFlightWriteFilePreview } from "@/core/artifacts/write-file-in-flight";
+import { shouldAutoOpenWritingArtifact } from "@/core/threads/writing-mode";
 import { getBackendBaseURL } from "@/core/config";
 import { isThreadRagModeLocked, useLocalSettings } from "@/core/settings";
 import { isSingleRoundRagMessage } from "@/core/threads/use-single-round-rag";
@@ -390,9 +391,12 @@ const ChatBox: React.FC<{
       ((artifactDirectoryModeEnabled && threadChanged) ||
         ((hasNewArtifact || !hadArtifacts) && !selectedArtifact))
     ) {
-      selectArtifact(nextArtifacts[nextArtifacts.length - 1]!);
-      setArtifactsOpen(true);
-      setSideTab("document");
+      const newest = nextArtifacts[nextArtifacts.length - 1]!;
+      if (shouldAutoOpenWritingArtifact(newest, thread.messages)) {
+        selectArtifact(newest);
+        setArtifactsOpen(true);
+        setSideTab("document");
+      }
     }
 
     // DO NOT automatically deselect the artifact when switching threads, because the artifacts auto discovering is not work now.
@@ -424,6 +428,7 @@ const ChatBox: React.FC<{
     setArtifacts,
     availableArtifacts,
     disableArtifacts,
+    thread.messages,
   ]);
 
   // Live sandbox: open as soon as any in-flight write_file has a path or

frontend-web/src/components/workspace/messages/message-group.tsx

@@ -69,6 +69,7 @@ import {
   type RuntimeDisplaySource,
 } from "@/core/skill-display/runtime";
 import { normalizeDisplaySources } from "@/core/skill-display/display-adapter";
+import { isInterceptedWritingReportWrite } from "@/core/threads/writing-mode";
 import { extractTitleFromMarkdown } from "@/core/utils/markdown";
 import { env } from "@/env";
 import { cn } from "@/lib/utils";
@@ -866,6 +867,22 @@ function convertToSteps(messages: Message[]): CoTStep[] {
         if (tool_call.name === "task") {
           continue;
         }
+        const writePath =
+          typeof (tool_call.args as { path?: unknown } | undefined)?.path === "string"
+            ? (tool_call.args as { path: string }).path
+            : "";
+        if (
+          (
+            tool_call.name === "write_file" ||
+            tool_call.name === "str_replace" ||
+            tool_call.name === "read_file" ||
+            tool_call.name === "read_multiple_files" ||
+            tool_call.name === "present_files"
+          ) &&
+          isInterceptedWritingReportWrite(writePath, message.id, messages)
+        ) {
+          continue;
+        }
         const step: CoTToolCallStep = {
           id: tool_call.id,
           messageId: message.id,