diff --git a/src/agents/agents.py b/src/agents/agents.py
index e1436e5..df94bd3 100644
--- a/src/agents/agents.py
+++ b/src/agents/agents.py
@@ -6,10 +6,10 @@ from typing import List, Optional
 
 from langgraph.prebuilt import create_react_agent
 
+from src.agents.tool_interceptor import wrap_tools_with_interceptor
 from src.config.agents import AGENT_LLM_MAP
 from src.llms.llm import get_llm_by_type
 from src.prompts import apply_prompt_template
-from src.agents.tool_interceptor import wrap_tools_with_interceptor
 
 logger = logging.getLogger(__name__)
 
diff --git a/src/agents/tool_interceptor.py b/src/agents/tool_interceptor.py
index b6d1d2b..5b7e459 100644
--- a/src/agents/tool_interceptor.py
+++ b/src/agents/tool_interceptor.py
@@ -8,6 +8,12 @@ from typing import Any, Callable, List, Optional
 from langchain_core.tools import BaseTool
 from langgraph.types import interrupt
 
+from src.utils.log_sanitizer import (
+    sanitize_feedback,
+    sanitize_log_input,
+    sanitize_tool_name,
+)
+
 logger = logging.getLogger(__name__)
 
 
@@ -84,27 +90,30 @@ class ToolInterceptor:
             BaseTool: The wrapped tool with interrupt capability
         """
         original_func = tool.func
-        logger.debug(f"Wrapping tool '{tool.name}' with interrupt capability")
+        safe_tool_name = sanitize_tool_name(tool.name)
+        logger.debug(f"Wrapping tool '{safe_tool_name}' with interrupt capability")
 
         def intercepted_func(*args: Any, **kwargs: Any) -> Any:
             """Execute the tool with interrupt check."""
             tool_name = tool.name
-            logger.debug(f"[ToolInterceptor] Executing tool: {tool_name}")
+            safe_tool_name_local = sanitize_tool_name(tool_name)
+            logger.debug(f"[ToolInterceptor] Executing tool: {safe_tool_name_local}")
             
             # Format tool input for display
             tool_input = args[0] if args else kwargs
             tool_input_repr = ToolInterceptor._format_tool_input(tool_input)
-            logger.debug(f"[ToolInterceptor] Tool input: {tool_input_repr[:200]}")
+            safe_tool_input = sanitize_log_input(tool_input_repr, max_length=100)
+            logger.debug(f"[ToolInterceptor] Tool input: {safe_tool_input}")
 
             should_interrupt = interceptor.should_interrupt(tool_name)
-            logger.debug(f"[ToolInterceptor] should_interrupt={should_interrupt} for tool '{tool_name}'")
+            logger.debug(f"[ToolInterceptor] should_interrupt={should_interrupt} for tool '{safe_tool_name_local}'")
             
             if should_interrupt:
                 logger.info(
-                    f"[ToolInterceptor] Interrupting before tool '{tool_name}'"
+                    f"[ToolInterceptor] Interrupting before tool '{safe_tool_name_local}'"
                 )
                 logger.debug(
-                    f"[ToolInterceptor] Interrupt message: About to execute tool '{tool_name}' with input: {tool_input_repr[:100]}..."
+                    f"[ToolInterceptor] Interrupt message: About to execute tool '{safe_tool_name_local}' with input: {safe_tool_input}..."
                 )
                 
                 # Trigger interrupt and wait for user feedback
@@ -112,41 +121,43 @@ class ToolInterceptor:
                     feedback = interrupt(
                         f"About to execute tool: '{tool_name}'\n\nInput:\n{tool_input_repr}\n\nApprove execution?"
                     )
-                    logger.debug(f"[ToolInterceptor] Interrupt returned with feedback: {f'{feedback[:100]}...' if feedback and len(feedback) > 100 else feedback if feedback else 'None'}")
+                    safe_feedback = sanitize_feedback(feedback)
+                    logger.debug(f"[ToolInterceptor] Interrupt returned with feedback: {f'{safe_feedback[:100]}...' if safe_feedback and len(safe_feedback) > 100 else safe_feedback if safe_feedback else 'None'}")
                 except Exception as e:
                     logger.error(f"[ToolInterceptor] Error during interrupt: {str(e)}")
                     raise
 
-                logger.debug(f"[ToolInterceptor] Processing feedback approval for '{tool_name}'")
+                logger.debug(f"[ToolInterceptor] Processing feedback approval for '{safe_tool_name_local}'")
                 
                 # Check if user approved
                 is_approved = ToolInterceptor._parse_approval(feedback)
-                logger.info(f"[ToolInterceptor] Tool '{tool_name}' approval decision: {is_approved}")
+                logger.info(f"[ToolInterceptor] Tool '{safe_tool_name_local}' approval decision: {is_approved}")
                 
                 if not is_approved:
-                    logger.warning(f"[ToolInterceptor] User rejected execution of tool '{tool_name}'")
+                    logger.warning(f"[ToolInterceptor] User rejected execution of tool '{safe_tool_name_local}'")
                     return {
                         "error": f"Tool execution rejected by user",
                         "tool": tool_name,
                         "status": "rejected",
                     }
 
-                logger.info(f"[ToolInterceptor] User approved execution of tool '{tool_name}', proceeding")
+                logger.info(f"[ToolInterceptor] User approved execution of tool '{safe_tool_name_local}', proceeding")
 
             # Execute the original tool
             try:
-                logger.debug(f"[ToolInterceptor] Calling original function for tool '{tool_name}'")
+                logger.debug(f"[ToolInterceptor] Calling original function for tool '{safe_tool_name_local}'")
                 result = original_func(*args, **kwargs)
-                logger.info(f"[ToolInterceptor] Tool '{tool_name}' execution completed successfully")
-                logger.debug(f"[ToolInterceptor] Tool result length: {len(str(result))}")
+                logger.info(f"[ToolInterceptor] Tool '{safe_tool_name_local}' execution completed successfully")
+                result_len = len(str(result))
+                logger.debug(f"[ToolInterceptor] Tool result length: {result_len}")
                 return result
             except Exception as e:
-                logger.error(f"[ToolInterceptor] Error executing tool '{tool_name}': {str(e)}")
+                logger.error(f"[ToolInterceptor] Error executing tool '{safe_tool_name_local}': {str(e)}")
                 raise
 
         # Replace the function and update the tool
         # Use object.__setattr__ to bypass Pydantic validation
-        logger.debug(f"Attaching intercepted function to tool '{tool.name}'")
+        logger.debug(f"Attaching intercepted function to tool '{safe_tool_name}'")
         object.__setattr__(tool, "func", intercepted_func)
         return tool
 
diff --git a/src/crawler/readability_extractor.py b/src/crawler/readability_extractor.py
index 87b3b97..698d5b6 100644
--- a/src/crawler/readability_extractor.py
+++ b/src/crawler/readability_extractor.py
@@ -2,6 +2,7 @@
 # SPDX-License-Identifier: MIT
 
 import logging
+
 from readabilipy import simple_json_from_html_string
 
 from .article import Article
diff --git a/src/server/app.py b/src/server/app.py
index 33bf7a8..9c3e545 100644
--- a/src/server/app.py
+++ b/src/server/app.py
@@ -55,6 +55,13 @@ from src.server.rag_request import (
 )
 from src.tools import VolcengineTTS
 from src.utils.json_utils import sanitize_args
+from src.utils.log_sanitizer import (
+    sanitize_agent_name,
+    sanitize_log_input,
+    sanitize_thread_id,
+    sanitize_tool_name,
+    sanitize_user_content,
+)
 
 logger = logging.getLogger(__name__)
 
@@ -333,9 +340,13 @@ def _process_initial_messages(message, thread_id):
 
 async def _process_message_chunk(message_chunk, message_metadata, thread_id, agent):
     """Process a single message chunk and yield appropriate events."""
+
     agent_name = _get_agent_name(agent, message_metadata)
-    logger.debug(f"[{thread_id}] _process_message_chunk started for agent_name={agent_name}")
-    logger.debug(f"[{thread_id}] Extracted agent_name: {agent_name}")
+    safe_agent_name = sanitize_agent_name(agent_name)
+    safe_thread_id = sanitize_thread_id(thread_id)
+    safe_agent = sanitize_agent_name(agent)
+    logger.debug(f"[{safe_thread_id}] _process_message_chunk started for agent={safe_agent_name}")
+    logger.debug(f"[{safe_thread_id}] Extracted agent_name: {safe_agent_name}")
     
     event_stream_message = _create_event_stream_message(
         message_chunk, message_metadata, thread_id, agent_name
@@ -343,25 +354,29 @@ async def _process_message_chunk(message_chunk, message_metadata, thread_id, age
 
     if isinstance(message_chunk, ToolMessage):
         # Tool Message - Return the result of the tool call
-        logger.debug(f"[{thread_id}] Processing ToolMessage")
+        logger.debug(f"[{safe_thread_id}] Processing ToolMessage")
         tool_call_id = message_chunk.tool_call_id
         event_stream_message["tool_call_id"] = tool_call_id
         
         # Validate tool_call_id for debugging
         if tool_call_id:
-            logger.debug(f"[{thread_id}] ToolMessage with tool_call_id: {tool_call_id}")
+            safe_tool_id = sanitize_log_input(tool_call_id, max_length=100)
+            logger.debug(f"[{safe_thread_id}] ToolMessage with tool_call_id: {safe_tool_id}")
         else:
-            logger.warning(f"[{thread_id}] ToolMessage received without tool_call_id")
+            logger.warning(f"[{safe_thread_id}] ToolMessage received without tool_call_id")
         
-        logger.debug(f"[{thread_id}] Yielding tool_call_result event")
+        logger.debug(f"[{safe_thread_id}] Yielding tool_call_result event")
         yield _make_event("tool_call_result", event_stream_message)
     elif isinstance(message_chunk, AIMessageChunk):
         # AI Message - Raw message tokens
-        logger.debug(f"[{thread_id}] Processing AIMessageChunk, tool_calls={bool(message_chunk.tool_calls)}, tool_call_chunks={bool(message_chunk.tool_call_chunks)}")
+        has_tool_calls = bool(message_chunk.tool_calls)
+        has_chunks = bool(message_chunk.tool_call_chunks)
+        logger.debug(f"[{safe_thread_id}] Processing AIMessageChunk, tool_calls={has_tool_calls}, tool_call_chunks={has_chunks}")
         
         if message_chunk.tool_calls:
             # AI Message - Tool Call (complete tool calls)
-            logger.debug(f"[{thread_id}] AIMessageChunk has complete tool_calls: {[tc.get('name', 'unknown') for tc in message_chunk.tool_calls]}")
+            safe_tool_names = [sanitize_tool_name(tc.get('name', 'unknown')) for tc in message_chunk.tool_calls]
+            logger.debug(f"[{safe_thread_id}] AIMessageChunk has complete tool_calls: {safe_tool_names}")
             event_stream_message["tool_calls"] = message_chunk.tool_calls
             
             # Process tool_call_chunks with proper index-based grouping
@@ -370,16 +385,18 @@ async def _process_message_chunk(message_chunk, message_metadata, thread_id, age
             )
             if processed_chunks:
                 event_stream_message["tool_call_chunks"] = processed_chunks
+                safe_chunk_names = [sanitize_tool_name(c.get('name')) for c in processed_chunks]
                 logger.debug(
-                    f"[{thread_id}] Tool calls: {[tc.get('name') for tc in message_chunk.tool_calls]}, "
+                    f"[{safe_thread_id}] Tool calls: {safe_tool_names}, "
                     f"Processed chunks: {len(processed_chunks)}"
                 )
             
-            logger.debug(f"[{thread_id}] Yielding tool_calls event")
+            logger.debug(f"[{safe_thread_id}] Yielding tool_calls event")
             yield _make_event("tool_calls", event_stream_message)
         elif message_chunk.tool_call_chunks:
             # AI Message - Tool Call Chunks (streaming)
-            logger.debug(f"[{thread_id}] AIMessageChunk has streaming tool_call_chunks: {len(message_chunk.tool_call_chunks)} chunks")
+            chunks_count = len(message_chunk.tool_call_chunks)
+            logger.debug(f"[{safe_thread_id}] AIMessageChunk has streaming tool_call_chunks: {chunks_count} chunks")
             processed_chunks = _process_tool_call_chunks(
                 message_chunk.tool_call_chunks
             )
@@ -392,26 +409,30 @@ async def _process_message_chunk(message_chunk, message_metadata, thread_id, age
                     
                     # Log index transitions to detect tool call boundaries
                     if prev_chunk is not None and current_index != prev_chunk.get("index"):
+                        prev_name = sanitize_tool_name(prev_chunk.get('name'))
+                        curr_name = sanitize_tool_name(chunk.get('name'))
                         logger.debug(
-                            f"[{thread_id}] Tool call boundary detected: "
-                            f"index {prev_chunk.get('index')} ({prev_chunk.get('name')}) -> "
-                            f"{current_index} ({chunk.get('name')})"
+                            f"[{safe_thread_id}] Tool call boundary detected: "
+                            f"index {prev_chunk.get('index')} ({prev_name}) -> "
+                            f"{current_index} ({curr_name})"
                         )
                     
                     prev_chunk = chunk
                 
                 # Include all processed chunks in the event
                 event_stream_message["tool_call_chunks"] = processed_chunks
+                safe_chunk_names = [sanitize_tool_name(c.get('name')) for c in processed_chunks]
                 logger.debug(
-                    f"[{thread_id}] Streamed {len(processed_chunks)} tool call chunk(s): "
-                    f"{[c.get('name') for c in processed_chunks]}"
+                    f"[{safe_thread_id}] Streamed {len(processed_chunks)} tool call chunk(s): "
+                    f"{safe_chunk_names}"
                 )
             
-            logger.debug(f"[{thread_id}] Yielding tool_call_chunks event")
+            logger.debug(f"[{safe_thread_id}] Yielding tool_call_chunks event")
             yield _make_event("tool_call_chunks", event_stream_message)
         else:
             # AI Message - Raw message tokens
-            logger.debug(f"[{thread_id}] AIMessageChunk is raw message tokens, content_len={len(message_chunk.content) if isinstance(message_chunk.content, str) else 'unknown'}")
+            content_len = len(message_chunk.content) if isinstance(message_chunk.content, str) else 0
+            logger.debug(f"[{safe_thread_id}] AIMessageChunk is raw message tokens, content_len={content_len}")
             yield _make_event("message_chunk", event_stream_message)
 
 
@@ -419,7 +440,8 @@ async def _stream_graph_events(
     graph_instance, workflow_input, workflow_config, thread_id
 ):
     """Stream events from the graph and process them."""
-    logger.debug(f"[{thread_id}] Starting graph event stream with agent nodes")
+    safe_thread_id = sanitize_thread_id(thread_id)
+    logger.debug(f"[{safe_thread_id}] Starting graph event stream with agent nodes")
     try:
         event_count = 0
         async for agent, _, event_data in graph_instance.astream(
@@ -429,28 +451,31 @@ async def _stream_graph_events(
             subgraphs=True,
         ):
             event_count += 1
-            logger.debug(f"[{thread_id}] Graph event #{event_count} received from agent: {agent}")
+            safe_agent = sanitize_agent_name(agent)
+            logger.debug(f"[{safe_thread_id}] Graph event #{event_count} received from agent: {safe_agent}")
             
             if isinstance(event_data, dict):
                 if "__interrupt__" in event_data:
                     logger.debug(
-                        f"[{thread_id}] Processing interrupt event: "
+                        f"[{safe_thread_id}] Processing interrupt event: "
                         f"ns={getattr(event_data['__interrupt__'][0], 'ns', 'unknown') if isinstance(event_data['__interrupt__'], (list, tuple)) and len(event_data['__interrupt__']) > 0 else 'unknown'}, "
                         f"value_len={len(getattr(event_data['__interrupt__'][0], 'value', '')) if isinstance(event_data['__interrupt__'], (list, tuple)) and len(event_data['__interrupt__']) > 0 and hasattr(event_data['__interrupt__'][0], 'value') and hasattr(event_data['__interrupt__'][0].value, '__len__') else 'unknown'}"
                     )
                     yield _create_interrupt_event(thread_id, event_data)
-                logger.debug(f"[{thread_id}] Dict event without interrupt, skipping")
+                logger.debug(f"[{safe_thread_id}] Dict event without interrupt, skipping")
                 continue
 
             message_chunk, message_metadata = cast(
                 tuple[BaseMessage, dict[str, Any]], event_data
             )
             
+            safe_node = sanitize_agent_name(message_metadata.get('langgraph_node', 'unknown'))
+            safe_step = sanitize_log_input(message_metadata.get('langgraph_step', 'unknown'))
             logger.debug(
-                f"[{thread_id}] Processing message chunk: "
+                f"[{safe_thread_id}] Processing message chunk: "
                 f"type={type(message_chunk).__name__}, "
-                f"node={message_metadata.get('langgraph_node', 'unknown')}, "
-                f"step={message_metadata.get('langgraph_step', 'unknown')}"
+                f"node={safe_node}, "
+                f"step={safe_step}"
             )
 
             async for event in _process_message_chunk(
@@ -458,9 +483,9 @@ async def _stream_graph_events(
             ):
                 yield event
         
-        logger.debug(f"[{thread_id}] Graph event stream completed. Total events: {event_count}")
+        logger.debug(f"[{safe_thread_id}] Graph event stream completed. Total events: {event_count}")
     except Exception as e:
-        logger.exception(f"[{thread_id}] Error during graph execution")
+        logger.exception(f"[{safe_thread_id}] Error during graph execution")
         yield _make_event(
             "error",
             {
@@ -488,34 +513,38 @@ async def _astream_workflow_generator(
     locale: str = "en-US",
     interrupt_before_tools: Optional[List[str]] = None,
 ):
+    safe_thread_id = sanitize_thread_id(thread_id)
+    safe_feedback = sanitize_log_input(interrupt_feedback) if interrupt_feedback else ""
     logger.debug(
-        f"[{thread_id}] _astream_workflow_generator starting: "
+        f"[{safe_thread_id}] _astream_workflow_generator starting: "
         f"messages_count={len(messages)}, "
         f"auto_accepted_plan={auto_accepted_plan}, "
-        f"interrupt_feedback={interrupt_feedback}, "
+        f"interrupt_feedback={safe_feedback}, "
         f"interrupt_before_tools={interrupt_before_tools}"
     )
     
     # Process initial messages
-    logger.debug(f"[{thread_id}] Processing {len(messages)} initial messages")
+    logger.debug(f"[{safe_thread_id}] Processing {len(messages)} initial messages")
     for message in messages:
         if isinstance(message, dict) and "content" in message:
-            logger.debug(f"[{thread_id}] Sending initial message to client: {message.get('content', '')[:100]}")
+            safe_content = sanitize_user_content(message.get('content', ''))
+            logger.debug(f"[{safe_thread_id}] Sending initial message to client: {safe_content}")
             _process_initial_messages(message, thread_id)
 
-    logger.debug(f"[{thread_id}] Reconstructing clarification history")
+    logger.debug(f"[{safe_thread_id}] Reconstructing clarification history")
     clarification_history = reconstruct_clarification_history(messages)
 
-    logger.debug(f"[{thread_id}] Building clarified topic from history")
+    logger.debug(f"[{safe_thread_id}] Building clarified topic from history")
     clarified_topic, clarification_history = build_clarified_topic_from_history(
         clarification_history
     )
     latest_message_content = messages[-1]["content"] if messages else ""
     clarified_research_topic = clarified_topic or latest_message_content
-    logger.debug(f"[{thread_id}] Clarified research topic: {clarified_research_topic[:100]}")
+    safe_topic = sanitize_user_content(clarified_research_topic)
+    logger.debug(f"[{safe_thread_id}] Clarified research topic: {safe_topic}")
 
     # Prepare workflow input
-    logger.debug(f"[{thread_id}] Preparing workflow input")
+    logger.debug(f"[{safe_thread_id}] Preparing workflow input")
     workflow_input = {
         "messages": messages,
         "plan_iterations": 0,
@@ -533,7 +562,7 @@ async def _astream_workflow_generator(
     }
 
     if not auto_accepted_plan and interrupt_feedback:
-        logger.debug(f"[{thread_id}] Creating resume command with interrupt_feedback: {interrupt_feedback}")
+        logger.debug(f"[{safe_thread_id}] Creating resume command with interrupt_feedback: {safe_feedback}")
         resume_msg = f"[{interrupt_feedback}]"
         if messages:
             resume_msg += f" {messages[-1]['content']}"
@@ -541,7 +570,7 @@ async def _astream_workflow_generator(
 
     # Prepare workflow config
     logger.debug(
-        f"[{thread_id}] Preparing workflow config: "
+        f"[{safe_thread_id}] Preparing workflow config: "
         f"max_plan_iterations={max_plan_iterations}, "
         f"max_step_num={max_step_num}, "
         f"report_style={report_style.value}, "
@@ -564,7 +593,7 @@ async def _astream_workflow_generator(
     checkpoint_url = get_str_env("LANGGRAPH_CHECKPOINT_DB_URL", "")
     
     logger.debug(
-        f"[{thread_id}] Checkpoint configuration: "
+        f"[{safe_thread_id}] Checkpoint configuration: "
         f"saver_enabled={checkpoint_saver}, "
         f"url_configured={bool(checkpoint_url)}"
     )
@@ -577,48 +606,48 @@ async def _astream_workflow_generator(
     }
     if checkpoint_saver and checkpoint_url != "":
         if checkpoint_url.startswith("postgresql://"):
-            logger.info(f"[{thread_id}] Starting async postgres checkpointer")
-            logger.debug(f"[{thread_id}] Setting up PostgreSQL connection pool")
+            logger.info(f"[{safe_thread_id}] Starting async postgres checkpointer")
+            logger.debug(f"[{safe_thread_id}] Setting up PostgreSQL connection pool")
             async with AsyncConnectionPool(
                 checkpoint_url, kwargs=connection_kwargs
             ) as conn:
-                logger.debug(f"[{thread_id}] Initializing AsyncPostgresSaver")
+                logger.debug(f"[{safe_thread_id}] Initializing AsyncPostgresSaver")
                 checkpointer = AsyncPostgresSaver(conn)
                 await checkpointer.setup()
-                logger.debug(f"[{thread_id}] Attaching checkpointer to graph")
+                logger.debug(f"[{safe_thread_id}] Attaching checkpointer to graph")
                 graph.checkpointer = checkpointer
                 graph.store = in_memory_store
-                logger.debug(f"[{thread_id}] Starting to stream graph events")
+                logger.debug(f"[{safe_thread_id}] Starting to stream graph events")
                 async for event in _stream_graph_events(
                     graph, workflow_input, workflow_config, thread_id
                 ):
                     yield event
-                logger.debug(f"[{thread_id}] Graph event streaming completed")
+                logger.debug(f"[{safe_thread_id}] Graph event streaming completed")
 
         if checkpoint_url.startswith("mongodb://"):
-            logger.info(f"[{thread_id}] Starting async mongodb checkpointer")
-            logger.debug(f"[{thread_id}] Setting up MongoDB connection")
+            logger.info(f"[{safe_thread_id}] Starting async mongodb checkpointer")
+            logger.debug(f"[{safe_thread_id}] Setting up MongoDB connection")
             async with AsyncMongoDBSaver.from_conn_string(
                 checkpoint_url
             ) as checkpointer:
-                logger.debug(f"[{thread_id}] Attaching MongoDB checkpointer to graph")
+                logger.debug(f"[{safe_thread_id}] Attaching MongoDB checkpointer to graph")
                 graph.checkpointer = checkpointer
                 graph.store = in_memory_store
-                logger.debug(f"[{thread_id}] Starting to stream graph events")
+                logger.debug(f"[{safe_thread_id}] Starting to stream graph events")
                 async for event in _stream_graph_events(
                     graph, workflow_input, workflow_config, thread_id
                 ):
                     yield event
-                logger.debug(f"[{thread_id}] Graph event streaming completed")
+                logger.debug(f"[{safe_thread_id}] Graph event streaming completed")
     else:
-        logger.debug(f"[{thread_id}] No checkpointer configured, using in-memory graph")
+        logger.debug(f"[{safe_thread_id}] No checkpointer configured, using in-memory graph")
         # Use graph without MongoDB checkpointer
-        logger.debug(f"[{thread_id}] Starting to stream graph events")
+        logger.debug(f"[{safe_thread_id}] Starting to stream graph events")
         async for event in _stream_graph_events(
             graph, workflow_input, workflow_config, thread_id
         ):
             yield event
-        logger.debug(f"[{thread_id}] Graph event streaming completed")
+        logger.debug(f"[{safe_thread_id}] Graph event streaming completed")
 
 
 def _make_event(event_type: str, data: dict[str, any]):
diff --git a/src/utils/log_sanitizer.py b/src/utils/log_sanitizer.py
new file mode 100644
index 0000000..b6f45fe
--- /dev/null
+++ b/src/utils/log_sanitizer.py
@@ -0,0 +1,186 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
+"""
+Log sanitization utilities to prevent log injection attacks.
+
+This module provides functions to sanitize user-controlled input before
+logging to prevent attackers from forging log entries through:
+- Newline injection (\n)
+- HTML injection (for HTML logs)
+- Special character sequences that could be misinterpreted
+"""
+
+import re
+from typing import Any, Optional
+
+
+def sanitize_log_input(value: Any, max_length: int = 500) -> str:
+    """
+    Sanitize user-controlled input for safe logging.
+
+    Replaces dangerous characters (newlines, tabs, carriage returns, etc.)
+    with their escaped representations to prevent log injection attacks.
+
+    Args:
+        value: The input value to sanitize (any type)
+        max_length: Maximum length of output string (truncates if exceeded)
+
+    Returns:
+        str: Sanitized string safe for logging
+
+    Examples:
+        >>> sanitize_log_input("normal text")
+        'normal text'
+
+        >>> sanitize_log_input("malicious\n[INFO] fake entry")
+        'malicious\\n[INFO] fake entry'
+
+        >>> sanitize_log_input("tab\there")
+        'tab\\there'
+
+        >>> sanitize_log_input(None)
+        'None'
+
+        >>> long_text = "a" * 1000
+        >>> result = sanitize_log_input(long_text, max_length=100)
+        >>> len(result) <= 100
+        True
+    """
+    if value is None:
+        return "None"
+
+    # Convert to string
+    string_value = str(value)
+
+    # Replace dangerous characters with their escaped representations
+    # Order matters: escape backslashes first to avoid double-escaping
+    replacements = {
+        "\\": "\\\\",  # Backslash (must be first)
+        "\n": "\\n",   # Newline - prevents creating new log entries
+        "\r": "\\r",   # Carriage return
+        "\t": "\\t",   # Tab
+        "\x00": "\\0",  # Null character
+        "\x1b": "\\x1b",  # Escape character (used in ANSI sequences)
+    }
+
+    for char, replacement in replacements.items():
+        string_value = string_value.replace(char, replacement)
+
+    # Remove other control characters (ASCII 0-31 except those already handled)
+    # These are rarely useful in logs and could be exploited
+    string_value = re.sub(r"[\x00-\x08\x0b-\x0c\x0e-\x1f]", "", string_value)
+
+    # Truncate if too long (prevent log flooding)
+    if len(string_value) > max_length:
+        string_value = string_value[: max_length - 3] + "..."
+
+    return string_value
+
+
+def sanitize_thread_id(thread_id: Any) -> str:
+    """
+    Sanitize thread_id for logging.
+
+    Thread IDs should be alphanumeric with hyphens and underscores,
+    but we sanitize to be defensive.
+
+    Args:
+        thread_id: The thread ID to sanitize
+
+    Returns:
+        str: Sanitized thread ID
+    """
+    return sanitize_log_input(thread_id, max_length=100)
+
+
+def sanitize_user_content(content: Any) -> str:
+    """
+    Sanitize user-provided message content for logging.
+
+    User messages can be arbitrary length, so we truncate more aggressively.
+
+    Args:
+        content: The user content to sanitize
+
+    Returns:
+        str: Sanitized user content
+    """
+    return sanitize_log_input(content, max_length=200)
+
+
+def sanitize_agent_name(agent_name: Any) -> str:
+    """
+    Sanitize agent name for logging.
+
+    Agent names should be simple identifiers, but we sanitize to be defensive.
+
+    Args:
+        agent_name: The agent name to sanitize
+
+    Returns:
+        str: Sanitized agent name
+    """
+    return sanitize_log_input(agent_name, max_length=100)
+
+
+def sanitize_tool_name(tool_name: Any) -> str:
+    """
+    Sanitize tool name for logging.
+
+    Tool names should be simple identifiers, but we sanitize to be defensive.
+
+    Args:
+        tool_name: The tool name to sanitize
+
+    Returns:
+        str: Sanitized tool name
+    """
+    return sanitize_log_input(tool_name, max_length=100)
+
+
+def sanitize_feedback(feedback: Any) -> str:
+    """
+    Sanitize user feedback for logging.
+
+    Feedback can be arbitrary text from interrupts, so sanitize carefully.
+
+    Args:
+        feedback: The feedback to sanitize
+
+    Returns:
+        str: Sanitized feedback (truncated more aggressively)
+    """
+    return sanitize_log_input(feedback, max_length=150)
+
+
+def create_safe_log_message(template: str, **kwargs) -> str:
+    """
+    Create a safe log message by sanitizing all values.
+
+    Uses a template string with keyword arguments, sanitizing each value
+    before substitution to prevent log injection.
+
+    Args:
+        template: Template string with {key} placeholders
+        **kwargs: Key-value pairs to substitute
+
+    Returns:
+        str: Safe log message
+
+    Example:
+        >>> msg = create_safe_log_message(
+        ...     "[{thread_id}] Processing {tool_name}",
+        ...     thread_id="abc\\n[INFO]",
+        ...     tool_name="my_tool"
+        ... )
+        >>> "[abc\\\\n[INFO]] Processing my_tool" in msg
+        True
+    """
+    # Sanitize all values
+    safe_kwargs = {
+        key: sanitize_log_input(value) for key, value in kwargs.items()
+    }
+
+    # Substitute into template
+    return template.format(**safe_kwargs)
diff --git a/tests/integration/test_tool_interceptor_integration.py b/tests/integration/test_tool_interceptor_integration.py
index a28fee4..20b017e 100644
--- a/tests/integration/test_tool_interceptor_integration.py
+++ b/tests/integration/test_tool_interceptor_integration.py
@@ -11,12 +11,12 @@ Tests the complete flow of selective tool interrupts including:
 - Resume mechanism after interrupt
 """
 
-import pytest
-from unittest.mock import Mock, patch, AsyncMock, MagicMock, call
 from typing import Any
+from unittest.mock import AsyncMock, MagicMock, Mock, call, patch
 
-from langchain_core.tools import tool
+import pytest
 from langchain_core.messages import HumanMessage
+from langchain_core.tools import tool
 
 from src.agents.agents import create_agent
 from src.agents.tool_interceptor import ToolInterceptor, wrap_tools_with_interceptor
diff --git a/tests/unit/agents/test_tool_interceptor.py b/tests/unit/agents/test_tool_interceptor.py
index 8fa37df..5be1cd7 100644
--- a/tests/unit/agents/test_tool_interceptor.py
+++ b/tests/unit/agents/test_tool_interceptor.py
@@ -1,9 +1,10 @@
 # Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
 # SPDX-License-Identifier: MIT
 
+from unittest.mock import AsyncMock, MagicMock, Mock, patch
+
 import pytest
-from unittest.mock import Mock, patch, MagicMock, AsyncMock
-from langchain_core.tools import tool, BaseTool
+from langchain_core.tools import BaseTool, tool
 
 from src.agents.tool_interceptor import (
     ToolInterceptor,
diff --git a/tests/unit/crawler/test_jina_client.py b/tests/unit/crawler/test_jina_client.py
index 94edade..087b5d2 100644
--- a/tests/unit/crawler/test_jina_client.py
+++ b/tests/unit/crawler/test_jina_client.py
@@ -1,8 +1,10 @@
 # Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
 # SPDX-License-Identifier: MIT
 
+from unittest.mock import Mock, patch
+
 import pytest
-from unittest.mock import patch, Mock
+
 from src.crawler.jina_client import JinaClient
 
 
diff --git a/tests/unit/crawler/test_readability_extractor.py b/tests/unit/crawler/test_readability_extractor.py
index 0e375fa..e4226e9 100644
--- a/tests/unit/crawler/test_readability_extractor.py
+++ b/tests/unit/crawler/test_readability_extractor.py
@@ -2,6 +2,7 @@
 # SPDX-License-Identifier: MIT
 
 from unittest.mock import patch
+
 from src.crawler.readability_extractor import ReadabilityExtractor
 
 
diff --git a/tests/unit/graph/test_plan_validation.py b/tests/unit/graph/test_plan_validation.py
index 64d6ac7..79fe3e7 100644
--- a/tests/unit/graph/test_plan_validation.py
+++ b/tests/unit/graph/test_plan_validation.py
@@ -1,8 +1,9 @@
 # Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
 # SPDX-License-Identifier: MIT
 
+from unittest.mock import MagicMock, patch
+
 import pytest
-from unittest.mock import patch, MagicMock
 
 from src.graph.nodes import validate_and_fix_plan
 
diff --git a/tests/unit/server/test_tool_call_chunks.py b/tests/unit/server/test_tool_call_chunks.py
index f4e017a..cd73360 100644
--- a/tests/unit/server/test_tool_call_chunks.py
+++ b/tests/unit/server/test_tool_call_chunks.py
@@ -10,13 +10,14 @@ tool names from being concatenated when multiple tool calls happen in sequence.
 """
 
 import logging
-import pytest
-from unittest.mock import patch, MagicMock
+import os
 
 # Import the functions to test
 # Note: We need to import from the app module
 import sys
-import os
+from unittest.mock import MagicMock, patch
+
+import pytest
 
 # Add src directory to path for imports
 sys.path.insert(0, os.path.join(os.path.dirname(__file__), "../../../"))
diff --git a/tests/unit/utils/test_json_utils.py b/tests/unit/utils/test_json_utils.py
index 0cc9795..e9ead1a 100644
--- a/tests/unit/utils/test_json_utils.py
+++ b/tests/unit/utils/test_json_utils.py
@@ -3,7 +3,11 @@
 
 import json
 
-from src.utils.json_utils import repair_json_output, sanitize_tool_response, _extract_json_from_content
+from src.utils.json_utils import (
+    _extract_json_from_content,
+    repair_json_output,
+    sanitize_tool_response,
+)
 
 
 class TestRepairJsonOutput:
diff --git a/tests/unit/utils/test_log_sanitizer.py b/tests/unit/utils/test_log_sanitizer.py
new file mode 100644
index 0000000..ffd989c
--- /dev/null
+++ b/tests/unit/utils/test_log_sanitizer.py
@@ -0,0 +1,268 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
+"""
+Unit tests for log sanitization utilities.
+
+This test file verifies that the log sanitizer properly prevents log injection attacks
+by escaping dangerous characters in user-controlled input before logging.
+"""
+
+import pytest
+
+from src.utils.log_sanitizer import (
+    create_safe_log_message,
+    sanitize_agent_name,
+    sanitize_feedback,
+    sanitize_log_input,
+    sanitize_thread_id,
+    sanitize_tool_name,
+    sanitize_user_content,
+)
+
+
+class TestSanitizeLogInput:
+    """Test the main sanitize_log_input function."""
+
+    def test_sanitize_normal_text(self):
+        """Test that normal text is preserved."""
+        text = "normal text"
+        result = sanitize_log_input(text)
+        assert result == "normal text"
+
+    def test_sanitize_newline_injection(self):
+        """Test prevention of newline injection attack."""
+        malicious = "abc\n[INFO] Forged log entry"
+        result = sanitize_log_input(malicious)
+        assert "\n" not in result
+        assert "[INFO]" in result  # The attack text is preserved but escaped
+        assert "\\n" in result  # Newline is escaped
+
+    def test_sanitize_carriage_return(self):
+        """Test prevention of carriage return injection."""
+        malicious = "text\r[WARN] Forged entry"
+        result = sanitize_log_input(malicious)
+        assert "\r" not in result
+        assert "\\r" in result
+
+    def test_sanitize_tab_character(self):
+        """Test prevention of tab character injection."""
+        malicious = "text\t[ERROR] Forged"
+        result = sanitize_log_input(malicious)
+        assert "\t" not in result
+        assert "\\t" in result
+
+    def test_sanitize_null_character(self):
+        """Test prevention of null character injection."""
+        malicious = "text\x00[CRITICAL]"
+        result = sanitize_log_input(malicious)
+        assert "\x00" not in result
+
+    def test_sanitize_backslash(self):
+        """Test that backslashes are properly escaped."""
+        text = "path\\to\\file"
+        result = sanitize_log_input(text)
+        assert result == "path\\\\to\\\\file"
+
+    def test_sanitize_escape_character(self):
+        """Test prevention of ANSI escape sequence injection."""
+        malicious = "text\x1b[31mRED TEXT\x1b[0m"
+        result = sanitize_log_input(malicious)
+        assert "\x1b" not in result
+        assert "\\x1b" in result
+
+    def test_sanitize_max_length_truncation(self):
+        """Test that long strings are truncated."""
+        long_text = "a" * 1000
+        result = sanitize_log_input(long_text, max_length=100)
+        assert len(result) <= 100
+        assert result.endswith("...")
+
+    def test_sanitize_none_value(self):
+        """Test that None is handled properly."""
+        result = sanitize_log_input(None)
+        assert result == "None"
+
+    def test_sanitize_numeric_value(self):
+        """Test that numeric values are converted to strings."""
+        result = sanitize_log_input(12345)
+        assert result == "12345"
+
+    def test_sanitize_complex_injection_attack(self):
+        """Test complex multi-character injection attack."""
+        malicious = 'thread-123\n[WARNING] Unauthorized\r[ERROR] System failure\t[CRITICAL] Shutdown'
+        result = sanitize_log_input(malicious)
+        # All dangerous characters should be escaped
+        assert "\n" not in result
+        assert "\r" not in result
+        assert "\t" not in result
+        # But the text should still be there (escaped)
+        assert "WARNING" in result
+        assert "ERROR" in result
+
+
+class TestSanitizeThreadId:
+    """Test sanitization of thread IDs."""
+
+    def test_thread_id_normal(self):
+        """Test normal thread ID."""
+        thread_id = "thread-123-abc"
+        result = sanitize_thread_id(thread_id)
+        assert result == "thread-123-abc"
+
+    def test_thread_id_with_newline(self):
+        """Test thread ID with newline injection."""
+        malicious = "thread-1\n[INFO] Forged"
+        result = sanitize_thread_id(malicious)
+        assert "\n" not in result
+        assert "\\n" in result
+
+    def test_thread_id_max_length(self):
+        """Test that thread ID truncation respects max length."""
+        long_id = "x" * 200
+        result = sanitize_thread_id(long_id)
+        assert len(result) <= 100
+
+
+class TestSanitizeUserContent:
+    """Test sanitization of user-provided message content."""
+
+    def test_user_content_normal(self):
+        """Test normal user content."""
+        content = "What is the weather today?"
+        result = sanitize_user_content(content)
+        assert result == "What is the weather today?"
+
+    def test_user_content_with_newline(self):
+        """Test user content with newline."""
+        malicious = "My question\n[ADMIN] Delete user"
+        result = sanitize_user_content(malicious)
+        assert "\n" not in result
+        assert "\\n" in result
+
+    def test_user_content_max_length(self):
+        """Test that user content is truncated more aggressively."""
+        long_content = "x" * 500
+        result = sanitize_user_content(long_content)
+        assert len(result) <= 200
+
+
+class TestSanitizeToolName:
+    """Test sanitization of tool names."""
+
+    def test_tool_name_normal(self):
+        """Test normal tool name."""
+        tool = "web_search"
+        result = sanitize_tool_name(tool)
+        assert result == "web_search"
+
+    def test_tool_name_injection(self):
+        """Test tool name with injection attempt."""
+        malicious = "search\n[WARN] Forged"
+        result = sanitize_tool_name(malicious)
+        assert "\n" not in result
+
+
+class TestSanitizeFeedback:
+    """Test sanitization of user feedback."""
+
+    def test_feedback_normal(self):
+        """Test normal feedback."""
+        feedback = "[accepted]"
+        result = sanitize_feedback(feedback)
+        assert result == "[accepted]"
+
+    def test_feedback_injection(self):
+        """Test feedback with injection attempt."""
+        malicious = "[approved]\n[CRITICAL] System down"
+        result = sanitize_feedback(malicious)
+        assert "\n" not in result
+        assert "\\n" in result
+
+    def test_feedback_max_length(self):
+        """Test that feedback is truncated."""
+        long_feedback = "x" * 500
+        result = sanitize_feedback(long_feedback)
+        assert len(result) <= 150
+
+
+class TestCreateSafeLogMessage:
+    """Test the create_safe_log_message helper function."""
+
+    def test_safe_message_normal(self):
+        """Test normal message creation."""
+        msg = create_safe_log_message(
+            "[{thread_id}] Processing {tool_name}",
+            thread_id="thread-1",
+            tool_name="search",
+        )
+        assert "[thread-1] Processing search" == msg
+
+    def test_safe_message_with_injection(self):
+        """Test message creation with injected values."""
+        msg = create_safe_log_message(
+            "[{thread_id}] Tool: {tool_name}",
+            thread_id="id\n[INFO] Forged",
+            tool_name="search\r[ERROR]",
+        )
+        # The dangerous characters should be escaped
+        assert "\n" not in msg
+        assert "\r" not in msg
+        assert "\\n" in msg
+        assert "\\r" in msg
+
+    def test_safe_message_multiple_values(self):
+        """Test message with multiple values."""
+        msg = create_safe_log_message(
+            "[{id}] User: {user} Tool: {tool}",
+            id="123",
+            user="admin\t[WARN]",
+            tool="delete\x1b[31m",
+        )
+        assert "\t" not in msg
+        assert "\x1b" not in msg
+
+
+class TestLogInjectionAttackPrevention:
+    """Integration tests for log injection prevention."""
+
+    def test_classic_log_injection_newline(self):
+        """Test the classic log injection attack using newlines."""
+        attacker_input = 'abc\n[WARNING] Unauthorized access detected'
+        result = sanitize_log_input(attacker_input)
+        # The output should not contain an actual newline that would create a new log entry
+        assert result.count("\n") == 0
+        # But the escaped version should be in there
+        assert "\\n" in result
+
+    def test_carriage_return_log_injection(self):
+        """Test log injection via carriage return."""
+        attacker_input = "request_id\r\n[ERROR] CRITICAL FAILURE"
+        result = sanitize_log_input(attacker_input)
+        assert "\r" not in result
+        assert "\n" not in result
+
+    def test_html_injection_prevention(self):
+        """Test prevention of HTML injection in logs."""
+        # While HTML tags themselves aren't dangerous in log files,
+        # escaping control characters helps prevent parsing attacks
+        malicious_html = "user\x1b[32m<script>alert('xss')</script>"
+        result = sanitize_log_input(malicious_html)
+        assert "\x1b" not in result
+        # HTML is preserved but with escaped control chars
+        assert "<script>" in result
+
+    def test_multiple_injection_techniques(self):
+        """Test prevention of multiple injection techniques combined."""
+        attack = 'id_1\n\r\t[CRITICAL]\x1b[31m RED TEXT'
+        result = sanitize_log_input(attack)
+        # No actual control characters should exist
+        assert "\n" not in result
+        assert "\r" not in result
+        assert "\t" not in result
+        assert "\x1b" not in result
+        # But escaped versions should exist
+        assert "\\n" in result
+        assert "\\r" in result
+        assert "\\t" in result
+        assert "\\x1b" in result