diff --git a/deepdoc/parser/pdf_parser.py b/deepdoc/parser/pdf_parser.py
index 2fb041e87..74e08e212 100644
--- a/deepdoc/parser/pdf_parser.py
+++ b/deepdoc/parser/pdf_parser.py
@@ -997,7 +997,7 @@ class RAGFlowPdfParser:
                 self.__ocr(i + 1, img, chars, zoomin, id)
 
             if callback and i % 6 == 5:
-                callback((i + 1) * 0.6 / len(self.page_images), msg="")
+                callback((i + 1) * 0.6 / len(self.page_images))
 
         async def __img_ocr_launcher():
             def __ocr_preprocess():
diff --git a/rag/flow/splitter/schema.py b/rag/flow/splitter/schema.py
index 9144a4d9b..9875d652c 100644
--- a/rag/flow/splitter/schema.py
+++ b/rag/flow/splitter/schema.py
@@ -25,7 +25,7 @@ class SplitterFromUpstream(BaseModel):
     file: dict | None = Field(default=None)
     chunks: list[dict[str, Any]] | None = Field(default=None)
 
-    output_format: Literal["json", "markdown", "text", "html"] | None = Field(default=None)
+    output_format: Literal["json", "markdown", "text", "html", "chunks"] | None = Field(default=None)
 
     json_result: list[dict[str, Any]] | None = Field(default=None, alias="json")
     markdown_result: str | None = Field(default=None, alias="markdown")
diff --git a/rag/flow/tokenizer/tokenizer.py b/rag/flow/tokenizer/tokenizer.py
index 425e20397..23e179496 100644
--- a/rag/flow/tokenizer/tokenizer.py
+++ b/rag/flow/tokenizer/tokenizer.py
@@ -126,7 +126,7 @@ class Tokenizer(ProcessBase):
                     if ck.get("summary"):
                         ck["content_ltks"] = rag_tokenizer.tokenize(str(ck["summary"]))
                         ck["content_sm_ltks"] = rag_tokenizer.fine_grained_tokenize(ck["content_ltks"])
-                    else:
+                    elif ck.get("text"):
                         ck["content_ltks"] = rag_tokenizer.tokenize(ck["text"])
                         ck["content_sm_ltks"] = rag_tokenizer.fine_grained_tokenize(ck["content_ltks"])
                     if i % 100 == 99:
@@ -155,6 +155,8 @@ class Tokenizer(ProcessBase):
                 for i, ck in enumerate(chunks):
                     ck["title_tks"] = rag_tokenizer.tokenize(re.sub(r"\.[a-zA-Z]+$", "", from_upstream.name))
                     ck["title_sm_tks"] = rag_tokenizer.fine_grained_tokenize(ck["title_tks"])
+                    if not ck.get("text"):
+                        continue
                     ck["content_ltks"] = rag_tokenizer.tokenize(ck["text"])
                     ck["content_sm_ltks"] = rag_tokenizer.fine_grained_tokenize(ck["content_ltks"])
                     if i % 100 == 99:
diff --git a/rag/nlp/__init__.py b/rag/nlp/__init__.py
index 736298679..871190d26 100644
--- a/rag/nlp/__init__.py
+++ b/rag/nlp/__init__.py
@@ -613,13 +613,13 @@ def naive_merge(sections: str | list, chunk_token_num=128, delimiter="\n。；
     dels = get_delimiters(delimiter)
     for sec, pos in sections:
         if num_tokens_from_string(sec) < chunk_token_num:
-            add_chunk(sec, pos)
+            add_chunk("\n"+sec, pos)
             continue
         split_sec = re.split(r"(%s)" % dels, sec, flags=re.DOTALL)
         for sub_sec in split_sec:
             if re.match(f"^{dels}$", sub_sec):
                 continue
-            add_chunk(sub_sec, pos)
+            add_chunk("\n"+sub_sec, pos)
 
     return cks
 
@@ -669,13 +669,13 @@ def naive_merge_with_images(texts, images, chunk_token_num=128, delimiter="\n。
             for sub_sec in split_sec:
                 if re.match(f"^{dels}$", sub_sec):
                     continue
-                add_chunk(sub_sec, image, text_pos)
+                add_chunk("\n"+sub_sec, image, text_pos)
         else:
             split_sec = re.split(r"(%s)" % dels, text)
             for sub_sec in split_sec:
                 if re.match(f"^{dels}$", sub_sec):
                     continue
-                add_chunk(sub_sec, image)
+                add_chunk("\n"+sub_sec, image)
 
     return cks, result_images
 
@@ -757,7 +757,7 @@ def naive_merge_docx(sections, chunk_token_num=128, delimiter="\n。；！？"):
         for sub_sec in split_sec:
             if re.match(f"^{dels}$", sub_sec):
                 continue
-            add_chunk(sub_sec, image,"")
+            add_chunk("\n"+sub_sec, image,"")
         line = ""
 
     if line:
@@ -765,7 +765,7 @@ def naive_merge_docx(sections, chunk_token_num=128, delimiter="\n。；！？"):
         for sub_sec in split_sec:
             if re.match(f"^{dels}$", sub_sec):
                 continue
-            add_chunk(sub_sec, image,"")
+            add_chunk("\n"+sub_sec, image,"")
 
     return cks, images
 
diff --git a/rag/prompts/generator.py b/rag/prompts/generator.py
index 73e1201f5..eda3e89ec 100644
--- a/rag/prompts/generator.py
+++ b/rag/prompts/generator.py
@@ -23,7 +23,7 @@ import jinja2
 import json_repair
 import trio
 from api.utils import hash_str2int
-from rag.nlp import is_chinese
+from rag.nlp import rag_tokenizer
 from rag.prompts.template import load_prompt
 from rag.settings import TAG_FLD
 from rag.utils import encoder, num_tokens_from_string
@@ -672,7 +672,7 @@ def assign_toc_levels(toc_secs, chat_mdl, gen_conf = {"temperature": 0.2}):
 TOC_FROM_TEXT_SYSTEM = load_prompt("toc_from_text_system")
 TOC_FROM_TEXT_USER = load_prompt("toc_from_text_user")
 # Generate TOC from text chunks with text llms
-async def gen_toc_from_text(txt_info: dict, chat_mdl):
+async def gen_toc_from_text(txt_info: dict, chat_mdl, callback=None):
     try:
         ans = gen_json(
             PROMPT_JINJA_ENV.from_string(TOC_FROM_TEXT_SYSTEM).render(),
@@ -682,6 +682,8 @@ async def gen_toc_from_text(txt_info: dict, chat_mdl):
         )
         print(ans, "::::::::::::::::::::::::::::::::::::", flush=True)
         txt_info["toc"] = ans if ans else []
+        if callback:
+            callback(msg="")
     except Exception as e:
         logging.exception(e)
 
@@ -707,14 +709,14 @@ def split_chunks(chunks, max_length: int):
     return result
 
 
-async def run_toc_from_text(chunks, chat_mdl):
+async def run_toc_from_text(chunks, chat_mdl, callback=None):
     input_budget = int(chat_mdl.max_length * INPUT_UTILIZATION) - num_tokens_from_string(
         TOC_FROM_TEXT_USER + TOC_FROM_TEXT_SYSTEM
     )
 
     input_budget =  1024 if input_budget > 1024 else input_budget
     chunk_sections = split_chunks(chunks, input_budget)
-    res = []
+    titles = []
 
     chunks_res = []
     async with trio.open_nursery() as nursery:
@@ -722,21 +724,21 @@ async def run_toc_from_text(chunks, chat_mdl):
             if not chunk:
                 continue
             chunks_res.append({"chunks": chunk})
-            nursery.start_soon(gen_toc_from_text, chunks_res[-1], chat_mdl)
+            nursery.start_soon(gen_toc_from_text, chunks_res[-1], chat_mdl, callback)
 
     for chunk in chunks_res:
-        res.extend(chunk.get("toc", []))
+        titles.extend(chunk.get("toc", []))
 
-    print(res, ">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>")
+    print(titles, ">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>")
         
     # Filter out entries with title == -1
+    prune = len(titles) > 512
+    max_len = 12 if prune else 22
     filtered = []
-    for x in res:
+    for x in titles:
         if not x.get("title") or x["title"] == "-1":
             continue
-        if is_chinese(x["title"]) and len(x["title"]) > 12:
-            continue
-        if len(x["title"].split(" ")) > 12:
+        if len(rag_tokenizer.tokenize(x["title"]).split(" ")) > max_len:
             continue
         if re.match(r"[0-9,.()/ -]+$", x["title"]):
             continue
@@ -751,8 +753,12 @@ async def run_toc_from_text(chunks, chat_mdl):
     toc_with_levels = assign_toc_levels(raw_structure, chat_mdl, {"temperature": 0.0, "top_p": 0.9})
 
     # Merge structure and content (by index)
+    prune = len(toc_with_levels) > 512
+    max_lvl = sorted([t.get("level", "0") for t in toc_with_levels])[-1]
     merged = []
     for _ , (toc_item, src_item) in enumerate(zip(toc_with_levels, filtered)):
+        if prune and toc_item.get("level", "0") >= max_lvl:
+            continue
         merged.append({
             "level": toc_item.get("level", "0"),
             "title": toc_item.get("title", ""),
@@ -776,7 +782,7 @@ def relevant_chunks_with_toc(query: str, toc:list[dict], chat_mdl, topn: int=6):
         print(ans, "::::::::::::::::::::::::::::::::::::", flush=True)
         id2score = {}
         for ti, sc in zip(toc, ans):
-            if sc.get("score", -1) < 1:
+            if not isinstance(sc, dict) or sc.get("score", -1) < 1:
                 continue
             for id in ti.get("ids", []):
                 if id not in id2score:
diff --git a/rag/svr/task_executor.py b/rag/svr/task_executor.py
index 08b232e49..c0b1d2c51 100644
--- a/rag/svr/task_executor.py
+++ b/rag/svr/task_executor.py
@@ -370,14 +370,14 @@ async def build_chunks(task, progress_callback):
                 nursery.start_soon(doc_question_proposal, chat_mdl, d, task["parser_config"]["auto_questions"])
         progress_callback(msg="Question generation {} chunks completed in {:.2f}s".format(len(docs), timer() - st))
 
-    if task["parser_config"].get("toc_extraction", True):
+    if task["parser_id"].lower() == "naive" and task["parser_config"].get("toc_extraction", False):
         progress_callback(msg="Start to generate table of content ...")
         chat_mdl = LLMBundle(task["tenant_id"], LLMType.CHAT, llm_name=task["llm_id"], lang=task["language"])
         docs = sorted(docs, key=lambda d:(
             d.get("page_num_int", 0)[0] if isinstance(d.get("page_num_int", 0), list) else d.get("page_num_int", 0),
             d.get("top_int", 0)[0] if isinstance(d.get("top_int", 0), list) else d.get("top_int", 0)
         ))
-        toc: list[dict] = await run_toc_from_text([d["content_with_weight"] for d in docs], chat_mdl)
+        toc: list[dict] = await run_toc_from_text([d["content_with_weight"] for d in docs], chat_mdl, progress_callback)
         logging.info("------------ T O C -------------\n"+json.dumps(toc, ensure_ascii=False, indent='  '))
         ii = 0
         while ii < len(toc):
@@ -387,7 +387,7 @@ async def build_chunks(task, progress_callback):
                 toc[ii]["ids"] = [docs[idx]["id"]]
                 if ii == len(toc) -1:
                     break
-                for jj in range(idx+1, int(toc[ii+1]["chunk_id"])):
+                for jj in range(idx+1, int(toc[ii+1]["chunk_id"])+1):
                     toc[ii]["ids"].append(docs[jj]["id"])
             except Exception as e:
                 logging.exception(e)