diff --git a/claude_code_log/cache.py b/claude_code_log/cache.py
index 7213da9b..d0a3ea00 100644
--- a/claude_code_log/cache.py
+++ b/claude_code_log/cache.py
@@ -3,7 +3,7 @@
 
 import json
 from pathlib import Path
-from typing import Any, Dict, List, Optional, cast
+from typing import Any, Optional, cast
 from datetime import datetime
 from pydantic import BaseModel
 from packaging import version
@@ -18,7 +18,7 @@ class CachedFileInfo(BaseModel):
     source_mtime: float
     cached_mtime: float
     message_count: int
-    session_ids: List[str]
+    session_ids: list[str]
 
 
 class SessionCacheData(BaseModel):
@@ -46,7 +46,7 @@ class ProjectCache(BaseModel):
     project_path: str
 
     # File-level cache information
-    cached_files: Dict[str, CachedFileInfo]
+    cached_files: dict[str, CachedFileInfo]
 
     # Aggregated project information
     total_message_count: int = 0
@@ -56,10 +56,10 @@ class ProjectCache(BaseModel):
     total_cache_read_tokens: int = 0
 
     # Session metadata
-    sessions: Dict[str, SessionCacheData]
+    sessions: dict[str, SessionCacheData]
 
     # Working directories associated with this project
-    working_directories: List[str] = []
+    working_directories: list[str] = []
 
     # Timeline information
     earliest_timestamp: str = ""
@@ -154,7 +154,7 @@ def is_file_cached(self, jsonl_path: Path) -> bool:
             abs(source_mtime - cached_info.source_mtime) < 1.0 and cache_file.exists()
         )
 
-    def load_cached_entries(self, jsonl_path: Path) -> Optional[List[TranscriptEntry]]:
+    def load_cached_entries(self, jsonl_path: Path) -> Optional[list[TranscriptEntry]]:
         """Load cached transcript entries for a JSONL file."""
         if not self.is_file_cached(jsonl_path):
             return None
@@ -165,11 +165,11 @@ def load_cached_entries(self, jsonl_path: Path) -> Optional[List[TranscriptEntry
                 cache_data = json.load(f)
 
             # Expect timestamp-keyed format - flatten all entries
-            entries_data: List[Dict[str, Any]] = []
+            entries_data: list[dict[str, Any]] = []
             for timestamp_entries in cache_data.values():
                 if isinstance(timestamp_entries, list):
-                    # Type cast to ensure Pyright knows this is List[Dict[str, Any]]
-                    entries_data.extend(cast(List[Dict[str, Any]], timestamp_entries))
+                    # Type cast to ensure Pyright knows this is list[dict[str, Any]]
+                    entries_data.extend(cast(list[dict[str, Any]], timestamp_entries))
 
             # Deserialize back to TranscriptEntry objects
             from .parser import parse_transcript_entry
@@ -184,7 +184,7 @@ def load_cached_entries(self, jsonl_path: Path) -> Optional[List[TranscriptEntry
 
     def load_cached_entries_filtered(
         self, jsonl_path: Path, from_date: Optional[str], to_date: Optional[str]
-    ) -> Optional[List[TranscriptEntry]]:
+    ) -> Optional[list[TranscriptEntry]]:
         """Load cached entries with efficient timestamp-based filtering."""
         if not self.is_file_cached(jsonl_path):
             return None
@@ -226,15 +226,15 @@ def load_cached_entries_filtered(
                         )
 
             # Filter entries by timestamp
-            filtered_entries_data: List[Dict[str, Any]] = []
+            filtered_entries_data: list[dict[str, Any]] = []
 
             for timestamp_key, timestamp_entries in cache_data.items():
                 if timestamp_key == "_no_timestamp":
                     # Always include entries without timestamps (like summaries)
                     if isinstance(timestamp_entries, list):
-                        # Type cast to ensure Pyright knows this is List[Dict[str, Any]]
+                        # Type cast to ensure Pyright knows this is list[dict[str, Any]]
                         filtered_entries_data.extend(
-                            cast(List[Dict[str, Any]], timestamp_entries)
+                            cast(list[dict[str, Any]], timestamp_entries)
                         )
                 else:
                     # Check if timestamp falls within range
@@ -251,9 +251,9 @@ def load_cached_entries_filtered(
                             continue
 
                     if isinstance(timestamp_entries, list):
-                        # Type cast to ensure Pyright knows this is List[Dict[str, Any]]
+                        # Type cast to ensure Pyright knows this is list[dict[str, Any]]
                         filtered_entries_data.extend(
-                            cast(List[Dict[str, Any]], timestamp_entries)
+                            cast(list[dict[str, Any]], timestamp_entries)
                         )
 
             # Deserialize filtered entries
@@ -271,14 +271,14 @@ def load_cached_entries_filtered(
             return None
 
     def save_cached_entries(
-        self, jsonl_path: Path, entries: List[TranscriptEntry]
+        self, jsonl_path: Path, entries: list[TranscriptEntry]
     ) -> None:
         """Save parsed transcript entries to cache with timestamp-based structure."""
         cache_file = self._get_cache_file_path(jsonl_path)
 
         try:
             # Create timestamp-keyed cache structure for efficient date filtering
-            cache_data: Dict[str, Any] = {}
+            cache_data: dict[str, Any] = {}
 
             for entry in entries:
                 # Get timestamp - use empty string as fallback for entries without timestamps
@@ -306,7 +306,7 @@ def save_cached_entries(
                 cached_mtime = cache_file.stat().st_mtime
 
                 # Extract session IDs from entries
-                session_ids: List[str] = []
+                session_ids: list[str] = []
                 for entry in entries:
                     if hasattr(entry, "sessionId"):
                         session_id = getattr(entry, "sessionId", "")
@@ -326,7 +326,7 @@ def save_cached_entries(
         except Exception as e:
             print(f"Warning: Failed to save cached entries to {cache_file}: {e}")
 
-    def update_session_cache(self, session_data: Dict[str, SessionCacheData]) -> None:
+    def update_session_cache(self, session_data: dict[str, SessionCacheData]) -> None:
         """Update cached session information."""
         if self._project_cache is None:
             return
@@ -360,7 +360,7 @@ def update_project_aggregates(
 
         self._save_project_cache()
 
-    def update_working_directories(self, working_directories: List[str]) -> None:
+    def update_working_directories(self, working_directories: list[str]) -> None:
         """Update the list of working directories associated with this project."""
         if self._project_cache is None:
             return
@@ -368,9 +368,9 @@ def update_working_directories(self, working_directories: List[str]) -> None:
         self._project_cache.working_directories = working_directories
         self._save_project_cache()
 
-    def get_modified_files(self, jsonl_files: List[Path]) -> List[Path]:
+    def get_modified_files(self, jsonl_files: list[Path]) -> list[Path]:
         """Get list of JSONL files that need to be reprocessed."""
-        modified_files: List[Path] = []
+        modified_files: list[Path] = []
 
         for jsonl_file in jsonl_files:
             if not self.is_file_cached(jsonl_file):
@@ -450,7 +450,7 @@ def _is_cache_version_compatible(self, cache_version: str) -> bool:
         # If no breaking changes affect this cache version, it's compatible
         return True
 
-    def get_cache_stats(self) -> Dict[str, Any]:
+    def get_cache_stats(self) -> dict[str, Any]:
         """Get cache statistics for reporting."""
         if self._project_cache is None:
             return {"cache_enabled": False}
diff --git a/claude_code_log/cli.py b/claude_code_log/cli.py
index 13ab85c9..285c1fc1 100644
--- a/claude_code_log/cli.py
+++ b/claude_code_log/cli.py
@@ -5,7 +5,7 @@
 import os
 import sys
 from pathlib import Path
-from typing import Optional, List
+from typing import Optional
 
 import click
 from git import Repo, InvalidGitRepositoryError
@@ -108,7 +108,7 @@ def convert_project_path_to_claude_dir(
 
 def find_projects_by_cwd(
     projects_dir: Path, current_cwd: Optional[str] = None
-) -> List[Path]:
+) -> list[Path]:
     """Find Claude projects that match the current working directory.
 
     Uses three-tier priority matching:
@@ -148,8 +148,8 @@ def find_projects_by_cwd(
 
 
 def _find_exact_matches(
-    project_dirs: List[Path], current_cwd_path: Path, base_projects_dir: Path
-) -> List[Path]:
+    project_dirs: list[Path], current_cwd_path: Path, base_projects_dir: Path
+) -> list[Path]:
     """Find projects with exact working directory matches using path-based matching."""
     expected_project_dir = convert_project_path_to_claude_dir(
         current_cwd_path, base_projects_dir
@@ -163,8 +163,8 @@ def _find_exact_matches(
 
 
 def _find_git_root_matches(
-    project_dirs: List[Path], current_cwd_path: Path, base_projects_dir: Path
-) -> List[Path]:
+    project_dirs: list[Path], current_cwd_path: Path, base_projects_dir: Path
+) -> list[Path]:
     """Find projects that match the git repository root using path-based matching."""
     try:
         # Check if we're inside a git repository
@@ -182,10 +182,10 @@ def _find_git_root_matches(
 
 
 def _find_relative_matches(
-    project_dirs: List[Path], current_cwd_path: Path
-) -> List[Path]:
+    project_dirs: list[Path], current_cwd_path: Path
+) -> list[Path]:
     """Find projects using relative path matching (original behavior)."""
-    relative_matches: List[Path] = []
+    relative_matches: list[Path] = []
 
     for project_dir in project_dirs:
         try:
diff --git a/claude_code_log/converter.py b/claude_code_log/converter.py
index 83e58ee6..960e8b4e 100644
--- a/claude_code_log/converter.py
+++ b/claude_code_log/converter.py
@@ -5,7 +5,7 @@
 import re
 from pathlib import Path
 import traceback
-from typing import List, Optional, Dict, Any, TYPE_CHECKING
+from typing import Optional, Any, TYPE_CHECKING
 
 import dateparser
 
@@ -39,18 +39,22 @@
 
 
 def filter_messages_by_date(
-    messages: List[TranscriptEntry], from_date: Optional[str], to_date: Optional[str]
-) -> List[TranscriptEntry]:
-    """Filter messages based on date range."""
+    messages: list[TranscriptEntry], from_date: Optional[str], to_date: Optional[str]
+) -> list[TranscriptEntry]:
+    """Filter messages based on date range.
+
+    Date parsing is done in UTC to match transcript timestamps which are stored in UTC.
+    """
     if not from_date and not to_date:
         return messages
 
-    # Parse the date strings using dateparser
+    # Parse dates in UTC to match transcript timestamps (which are stored in UTC)
+    dateparser_settings: Any = {"TIMEZONE": "UTC", "RETURN_AS_TIMEZONE_AWARE": False}
     from_dt = None
     to_dt = None
 
     if from_date:
-        from_dt = dateparser.parse(from_date)
+        from_dt = dateparser.parse(from_date, settings=dateparser_settings)
         if not from_dt:
             raise ValueError(f"Could not parse from-date: {from_date}")
         # If parsing relative dates like "today", start from beginning of day
@@ -58,14 +62,14 @@ def filter_messages_by_date(
             from_dt = from_dt.replace(hour=0, minute=0, second=0, microsecond=0)
 
     if to_date:
-        to_dt = dateparser.parse(to_date)
+        to_dt = dateparser.parse(to_date, settings=dateparser_settings)
         if not to_dt:
             raise ValueError(f"Could not parse to-date: {to_date}")
         # If parsing relative dates like "today", end at end of day
         if to_date in ["today", "yesterday"] or "days ago" in to_date:
             to_dt = to_dt.replace(hour=23, minute=59, second=59, microsecond=999999)
 
-    filtered_messages: List[TranscriptEntry] = []
+    filtered_messages: list[TranscriptEntry] = []
     for message in messages:
         # Handle SummaryTranscriptEntry which doesn't have timestamp
         if isinstance(message, SummaryTranscriptEntry):
@@ -102,7 +106,7 @@ def load_transcript(
     to_date: Optional[str] = None,
     silent: bool = False,
     _loaded_files: Optional[set[Path]] = None,
-) -> List[TranscriptEntry]:
+) -> list[TranscriptEntry]:
     """Load and parse JSONL transcript file, using cache if available.
 
     Args:
@@ -133,7 +137,7 @@ def load_transcript(
             return cached_entries
 
     # Parse from source file
-    messages: List[TranscriptEntry] = []
+    messages: list[TranscriptEntry] = []
     agent_ids: set[str] = set()  # Collect agentId references while parsing
 
     with open(jsonl_path, "r", encoding="utf-8", errors="replace") as f:
@@ -210,17 +214,17 @@ def load_transcript(
                     else:
                         print(
                             f"Line {line_no} of {jsonl_path} | ValueError: {error_msg}"
-                            "\n{traceback.format_exc()}"
+                            f"\n{traceback.format_exc()}"
                         )
                 except Exception as e:
                     print(
                         f"Line {line_no} of {jsonl_path} | Unexpected error: {str(e)}"
-                        "\n{traceback.format_exc()}"
+                        f"\n{traceback.format_exc()}"
                     )
 
     # Load agent files if any were referenced
     # Build a map of agentId -> agent messages
-    agent_messages_map: dict[str, List[TranscriptEntry]] = {}
+    agent_messages_map: dict[str, list[TranscriptEntry]] = {}
     if agent_ids:
         parent_dir = jsonl_path.parent
         for agent_id in agent_ids:
@@ -242,11 +246,11 @@ def load_transcript(
                 )
                 agent_messages_map[agent_id] = agent_messages
 
-    # Insert agent messages at their point of use
+    # Insert agent messages at their point of use (only once per agent)
     if agent_messages_map:
-        # Iterate through messages and insert agent messages after the message
+        # Iterate through messages and insert agent messages after the FIRST message
         # that references them (via UserTranscriptEntry.agentId)
-        result_messages: List[TranscriptEntry] = []
+        result_messages: list[TranscriptEntry] = []
         for message in messages:
             result_messages.append(message)
 
@@ -254,8 +258,8 @@ def load_transcript(
             if isinstance(message, UserTranscriptEntry) and message.agentId:
                 agent_id = message.agentId
                 if agent_id in agent_messages_map:
-                    # Insert agent messages right after this message
-                    result_messages.extend(agent_messages_map[agent_id])
+                    # Insert agent messages right after this message (pop to insert only once)
+                    result_messages.extend(agent_messages_map.pop(agent_id))
 
         messages = result_messages
 
@@ -272,12 +276,15 @@ def load_directory_transcripts(
     from_date: Optional[str] = None,
     to_date: Optional[str] = None,
     silent: bool = False,
-) -> List[TranscriptEntry]:
+) -> list[TranscriptEntry]:
     """Load all JSONL transcript files from a directory and combine them."""
-    all_messages: List[TranscriptEntry] = []
+    all_messages: list[TranscriptEntry] = []
 
-    # Find all .jsonl files
-    jsonl_files = list(directory_path.glob("*.jsonl"))
+    # Find all .jsonl files, excluding agent files (they are loaded via load_transcript
+    # when a session references them via agentId)
+    jsonl_files = [
+        f for f in directory_path.glob("*.jsonl") if not f.name.startswith("agent-")
+    ]
 
     for jsonl_file in jsonl_files:
         messages = load_transcript(
@@ -300,7 +307,7 @@ def get_timestamp(entry: TranscriptEntry) -> str:
 # =============================================================================
 
 
-def deduplicate_messages(messages: List[TranscriptEntry]) -> List[TranscriptEntry]:
+def deduplicate_messages(messages: list[TranscriptEntry]) -> list[TranscriptEntry]:
     """Remove duplicate messages based on (type, timestamp, sessionId, content_key).
 
     Messages with the exact same timestamp are duplicates by definition -
@@ -320,7 +327,7 @@ def deduplicate_messages(messages: List[TranscriptEntry]) -> List[TranscriptEntr
     """
     # Track seen (message_type, timestamp, is_meta, session_id, content_key) tuples
     seen: set[tuple[str, str, bool, str, str]] = set()
-    deduplicated: List[TranscriptEntry] = []
+    deduplicated: list[TranscriptEntry] = []
 
     for message in messages:
         # Get basic message type
@@ -343,6 +350,7 @@ def deduplicate_messages(messages: List[TranscriptEntry]) -> List[TranscriptEntr
         # Get content key for differentiating concurrent messages
         # - For assistant messages: use message.id (same for stutters, different for different msgs)
         # - For user messages with tool results: use first tool_use_id
+        # - For summary messages: use leafUuid (summaries have no timestamp/uuid)
         # - For other messages: use uuid as fallback
         content_key = ""
         if isinstance(message, AssistantTranscriptEntry):
@@ -350,11 +358,13 @@ def deduplicate_messages(messages: List[TranscriptEntry]) -> List[TranscriptEntr
             content_key = message.message.id
         elif isinstance(message, UserTranscriptEntry):
             # For user messages, check for tool results
-            if isinstance(message.message.content, list):
-                for item in message.message.content:
-                    if isinstance(item, ToolResultContent):
-                        content_key = item.tool_use_id
-                        break
+            for item in message.message.content:
+                if isinstance(item, ToolResultContent):
+                    content_key = item.tool_use_id
+                    break
+        elif isinstance(message, SummaryTranscriptEntry):
+            # Summaries have no timestamp or uuid - use leafUuid to keep them distinct
+            content_key = message.leafUuid
         # Fallback to uuid if no content key found
         if not content_key:
             content_key = getattr(message, "uuid", "")
@@ -455,7 +465,7 @@ def convert_jsonl_to(
 
     # Update title to include date range if specified
     if from_date or to_date:
-        date_range_parts: List[str] = []
+        date_range_parts: list[str] = []
         if from_date:
             date_range_parts.append(f"from {from_date}")
         if to_date:
@@ -512,21 +522,28 @@ def ensure_fresh_cache(
         return False
 
     # Check if cache needs updating
-    jsonl_files = list(project_dir.glob("*.jsonl"))
-    if not jsonl_files:
+    # Exclude agent files from direct check - they are loaded via session references
+    # Note: If only an agent file changes (session unchanged), cache won't detect it.
+    # This is acceptable since agent files typically change alongside their sessions.
+    session_jsonl_files = [
+        f for f in project_dir.glob("*.jsonl") if not f.name.startswith("agent-")
+    ]
+    if not session_jsonl_files:
         return False
 
     # Get cached project data
     cached_project_data = cache_manager.get_cached_project_data()
 
     # Check various invalidation conditions
-    modified_files = cache_manager.get_modified_files(jsonl_files)
+    modified_files = cache_manager.get_modified_files(session_jsonl_files)
     needs_update = (
         cached_project_data is None
         or from_date is not None
         or to_date is not None
-        or bool(modified_files)  # Files changed
-        or (cached_project_data.total_message_count == 0 and jsonl_files)  # Stale cache
+        or bool(modified_files)  # Session files changed
+        or (
+            cached_project_data.total_message_count == 0 and session_jsonl_files
+        )  # Stale cache
     )
 
     if not needs_update:
@@ -545,15 +562,15 @@ def ensure_fresh_cache(
 
 
 def _update_cache_with_session_data(
-    cache_manager: CacheManager, messages: List[TranscriptEntry]
+    cache_manager: CacheManager, messages: list[TranscriptEntry]
 ) -> None:
     """Update cache with session and project aggregate data."""
     from .parser import extract_text_content
 
     # Collect session data (similar to _collect_project_sessions but for cache)
-    session_summaries: Dict[str, str] = {}
-    uuid_to_session: Dict[str, str] = {}
-    uuid_to_session_backup: Dict[str, str] = {}
+    session_summaries: dict[str, str] = {}
+    uuid_to_session: dict[str, str] = {}
+    uuid_to_session_backup: dict[str, str] = {}
 
     # Build mapping from message UUID to session ID
     for message in messages:
@@ -579,7 +596,7 @@ def _update_cache_with_session_data(
                 session_summaries[uuid_to_session_backup[leaf_uuid]] = message.summary
 
     # Group messages by session and calculate session data
-    sessions_cache_data: Dict[str, SessionCacheData] = {}
+    sessions_cache_data: dict[str, SessionCacheData] = {}
 
     # Track token usage and timestamps for project aggregates
     total_input_tokens = 0
@@ -704,7 +721,7 @@ def _update_cache_with_session_data(
     )
 
 
-def _collect_project_sessions(messages: List[TranscriptEntry]) -> List[Dict[str, Any]]:
+def _collect_project_sessions(messages: list[TranscriptEntry]) -> list[dict[str, Any]]:
     """Collect session data for project index navigation."""
     from .parser import extract_text_content
 
@@ -713,9 +730,9 @@ def _collect_project_sessions(messages: List[TranscriptEntry]) -> List[Dict[str,
 
     # Pre-process to find and attach session summaries
     # This matches the logic from renderer.py generate_html() exactly
-    session_summaries: Dict[str, str] = {}
-    uuid_to_session: Dict[str, str] = {}
-    uuid_to_session_backup: Dict[str, str] = {}
+    session_summaries: dict[str, str] = {}
+    uuid_to_session: dict[str, str] = {}
+    uuid_to_session_backup: dict[str, str] = {}
 
     # Build mapping from message UUID to session ID across ALL messages
     # This allows summaries from later sessions to be matched to earlier sessions
@@ -745,7 +762,7 @@ def _collect_project_sessions(messages: List[TranscriptEntry]) -> List[Dict[str,
                 session_summaries[uuid_to_session_backup[leaf_uuid]] = message.summary
 
     # Group messages by session (excluding warmup-only sessions)
-    sessions: Dict[str, Dict[str, Any]] = {}
+    sessions: dict[str, dict[str, Any]] = {}
     for message in messages:
         if hasattr(message, "sessionId") and not isinstance(
             message, SummaryTranscriptEntry
@@ -782,13 +799,13 @@ def _collect_project_sessions(messages: List[TranscriptEntry]) -> List[Dict[str,
                     )
 
     # Convert to list format with formatted timestamps
-    session_list: List[Dict[str, Any]] = []
+    session_list: list[dict[str, Any]] = []
     for session_data in sessions.values():
         timestamp_range = format_timestamp_range(
             session_data["first_timestamp"],
             session_data["last_timestamp"],
         )
-        session_dict: Dict[str, Any] = {
+        session_dict: dict[str, Any] = {
             "id": session_data["id"],
             "summary": session_data["summary"],
             "timestamp_range": timestamp_range,
@@ -810,7 +827,7 @@ def _collect_project_sessions(messages: List[TranscriptEntry]) -> List[Dict[str,
 
 def _generate_individual_session_files(
     format: str,
-    messages: List[TranscriptEntry],
+    messages: list[TranscriptEntry],
     output_dir: Path,
     from_date: Optional[str] = None,
     to_date: Optional[str] = None,
@@ -830,7 +847,7 @@ def _generate_individual_session_files(
                 session_ids.add(session_id)
 
     # Get session data from cache for better titles
-    session_data: Dict[str, Any] = {}
+    session_data: dict[str, Any] = {}
     working_directories = None
     if cache_manager is not None:
         project_cache = cache_manager.get_cached_project_data()
@@ -842,6 +859,9 @@ def _generate_individual_session_files(
 
     project_title = get_project_display_name(output_dir.name, working_directories)
 
+    # Get renderer once outside the loop
+    renderer = get_renderer(format)
+
     # Generate HTML file for each session
     for session_id in session_ids:
         # Create session-specific title using cache data if available
@@ -865,7 +885,7 @@ def _generate_individual_session_files(
 
         # Add date range if specified
         if from_date or to_date:
-            date_range_parts: List[str] = []
+            date_range_parts: list[str] = []
             if from_date:
                 date_range_parts.append(f"from {from_date}")
             if to_date:
@@ -875,7 +895,6 @@ def _generate_individual_session_files(
 
         # Check if session file needs regeneration
         session_file_path = output_dir / f"session-{session_id}.{format}"
-        renderer = get_renderer(format)
 
         # Only regenerate if outdated, doesn't exist, or date filtering is active
         should_regenerate_session = (
@@ -912,7 +931,7 @@ def process_projects_hierarchy(
         raise FileNotFoundError(f"Projects path not found: {projects_path}")
 
     # Find all project directories (those with JSONL files)
-    project_dirs: List[Path] = []
+    project_dirs: list[Path] = []
     for child in projects_path.iterdir():
         if child.is_dir() and list(child.glob("*.jsonl")):
             project_dirs.append(child)
@@ -926,7 +945,7 @@ def process_projects_hierarchy(
     library_version = get_library_version()
 
     # Process each project directory
-    project_summaries: List[Dict[str, Any]] = []
+    project_summaries: list[dict[str, Any]] = []
     any_cache_updated = False  # Track if any project had cache updates
     for project_dir in sorted(project_dirs):
         try:
@@ -956,7 +975,12 @@ def process_projects_hierarchy(
             )
 
             # Get project info for index - use cached data if available
-            jsonl_files = list(project_dir.glob("*.jsonl"))
+            # Exclude agent files (they are loaded via session references)
+            jsonl_files = [
+                f
+                for f in project_dir.glob("*.jsonl")
+                if not f.name.startswith("agent-")
+            ]
             jsonl_count = len(jsonl_files)
             last_modified: float = (
                 max(f.stat().st_mtime for f in jsonl_files) if jsonl_files else 0.0
diff --git a/claude_code_log/html/ansi_colors.py b/claude_code_log/html/ansi_colors.py
index cd14f989..ab6085a7 100644
--- a/claude_code_log/html/ansi_colors.py
+++ b/claude_code_log/html/ansi_colors.py
@@ -7,7 +7,7 @@
 
 import html
 import re
-from typing import Any, Dict, List
+from typing import Any
 
 
 def _escape_html(text: str) -> str:
@@ -54,8 +54,8 @@ def convert_ansi_to_html(text: str) -> str:
     # This catches any we might have missed, but preserves \x1b[...m color codes
     text = re.sub(r"\x1b\[(?![0-9;]*m)[0-9;]*[A-Za-z]", "", text)
 
-    result: List[str] = []
-    segments: List[Dict[str, Any]] = []
+    result: list[str] = []
+    segments: list[dict[str, Any]] = []
 
     # First pass: split text into segments with their styles
     last_end = 0
@@ -68,7 +68,7 @@ def convert_ansi_to_html(text: str) -> str:
     current_rgb_fg = None
     current_rgb_bg = None
 
-    for match in re.finditer(r"\x1b\[([0-9;]+)m", text):
+    for match in re.finditer(r"\x1b\[([0-9;]*)m", text):
         # Add text before this escape code
         if match.start() > last_end:
             segments.append(
@@ -85,8 +85,11 @@ def convert_ansi_to_html(text: str) -> str:
                 }
             )
 
-        # Process escape codes
-        codes = match.group(1).split(";")
+        # Process escape codes (empty params = reset, same as code 0)
+        code_blob = match.group(1)
+        codes = code_blob.split(";") if code_blob else ["0"]
+        if codes == [""]:
+            codes = ["0"]
         i = 0
         while i < len(codes):
             code = codes[i]
@@ -189,16 +192,20 @@ def convert_ansi_to_html(text: str) -> str:
             elif code == "38" and i + 1 < len(codes) and codes[i + 1] == "2":
                 if i + 4 < len(codes):
                     r, g, b = codes[i + 2], codes[i + 3], codes[i + 4]
-                    current_rgb_fg = f"color: rgb({r}, {g}, {b})"
-                    current_fg = None
+                    # Validate RGB values are numeric to avoid invalid CSS
+                    if r.isdigit() and g.isdigit() and b.isdigit():
+                        current_rgb_fg = f"color: rgb({r}, {g}, {b})"
+                        current_fg = None
                     i += 4
 
             # RGB background color
             elif code == "48" and i + 1 < len(codes) and codes[i + 1] == "2":
                 if i + 4 < len(codes):
                     r, g, b = codes[i + 2], codes[i + 3], codes[i + 4]
-                    current_rgb_bg = f"background-color: rgb({r}, {g}, {b})"
-                    current_bg = None
+                    # Validate RGB values are numeric to avoid invalid CSS
+                    if r.isdigit() and g.isdigit() and b.isdigit():
+                        current_rgb_bg = f"background-color: rgb({r}, {g}, {b})"
+                        current_bg = None
                     i += 4
 
             i += 1
@@ -226,8 +233,8 @@ def convert_ansi_to_html(text: str) -> str:
         if not segment["text"]:
             continue
 
-        classes: List[str] = []
-        styles: List[str] = []
+        classes: list[str] = []
+        styles: list[str] = []
 
         if segment["fg"]:
             classes.append(segment["fg"])
@@ -249,7 +256,7 @@ def convert_ansi_to_html(text: str) -> str:
         escaped_text = _escape_html(segment["text"])
 
         if classes or styles:
-            attrs: List[str] = []
+            attrs: list[str] = []
             if classes:
                 attrs.append(f'class="{" ".join(classes)}"')
             if styles:
diff --git a/claude_code_log/html/renderer.py b/claude_code_log/html/renderer.py
index c2efdc8f..7c0e9dea 100644
--- a/claude_code_log/html/renderer.py
+++ b/claude_code_log/html/renderer.py
@@ -1,7 +1,7 @@
 """HTML renderer implementation for Claude Code transcripts."""
 
 from pathlib import Path
-from typing import TYPE_CHECKING, Any, Dict, List, Optional, Tuple
+from typing import TYPE_CHECKING, Any, Optional, Tuple
 
 from ..cache import get_library_version
 from ..models import (
@@ -168,8 +168,8 @@ def _format_message_content(self, message: TemplateMessage) -> str:
         return ""
 
     def _flatten_preorder(
-        self, roots: List[TemplateMessage]
-    ) -> List[Tuple[TemplateMessage, str]]:
+        self, roots: list[TemplateMessage]
+    ) -> list[Tuple[TemplateMessage, str]]:
         """Flatten message tree via pre-order traversal, formatting each message.
 
         Traverses the tree depth-first (pre-order), formats each message's
@@ -181,7 +181,7 @@ def _flatten_preorder(
         Returns:
             Flat list of (message, html_content) tuples in pre-order
         """
-        flat: List[Tuple[TemplateMessage, str]] = []
+        flat: list[Tuple[TemplateMessage, str]] = []
 
         def visit(msg: TemplateMessage) -> None:
             html = self._format_message_content(msg)
@@ -196,7 +196,7 @@ def visit(msg: TemplateMessage) -> None:
 
     def generate(
         self,
-        messages: List[TranscriptEntry],
+        messages: list[TranscriptEntry],
         title: Optional[str] = None,
         combined_transcript_link: Optional[str] = None,
     ) -> str:
@@ -239,7 +239,7 @@ def generate(
 
     def generate_session(
         self,
-        messages: List[TranscriptEntry],
+        messages: list[TranscriptEntry],
         session_id: str,
         title: Optional[str] = None,
         cache_manager: Optional["CacheManager"] = None,
@@ -266,7 +266,7 @@ def generate_session(
 
     def generate_projects_index(
         self,
-        project_summaries: List[Dict[str, Any]],
+        project_summaries: list[dict[str, Any]],
         from_date: Optional[str] = None,
         to_date: Optional[str] = None,
     ) -> str:
@@ -303,7 +303,7 @@ def is_outdated(self, file_path: Path) -> bool:
 
 
 def generate_html(
-    messages: List[TranscriptEntry],
+    messages: list[TranscriptEntry],
     title: Optional[str] = None,
     combined_transcript_link: Optional[str] = None,
 ) -> str:
@@ -315,7 +315,7 @@ def generate_html(
 
 
 def generate_session_html(
-    messages: List[TranscriptEntry],
+    messages: list[TranscriptEntry],
     session_id: str,
     title: Optional[str] = None,
     cache_manager: Optional["CacheManager"] = None,
@@ -325,7 +325,7 @@ def generate_session_html(
 
 
 def generate_projects_index_html(
-    project_summaries: List[Dict[str, Any]],
+    project_summaries: list[dict[str, Any]],
     from_date: Optional[str] = None,
     to_date: Optional[str] = None,
 ) -> str:
diff --git a/claude_code_log/html/renderer_code.py b/claude_code_log/html/renderer_code.py
index ab93f039..7a633d45 100644
--- a/claude_code_log/html/renderer_code.py
+++ b/claude_code_log/html/renderer_code.py
@@ -10,7 +10,7 @@
 import html
 import os
 import re
-from typing import Callable, List, Optional
+from typing import Callable, Optional
 
 from pygments import highlight  # type: ignore[reportUnknownVariableType]
 from pygments.lexers import TextLexer, get_lexer_by_name, get_all_lexers  # type: ignore[reportUnknownVariableType]
@@ -193,7 +193,7 @@ def render_line_diff(
     sm = difflib.SequenceMatcher(None, old_line.rstrip("\n"), new_line.rstrip("\n"))
 
     # Build old line with highlighting
-    old_parts: List[str] = []
+    old_parts: list[str] = []
     old_parts.append(
         "<div class='diff-line diff-removed'><span class='diff-marker'>-</span>"
     )
@@ -208,7 +208,7 @@ def render_line_diff(
     old_parts.append("</div>")
 
     # Build new line with highlighting
-    new_parts: List[str] = []
+    new_parts: list[str] = []
     new_parts.append(
         "<div class='diff-line diff-added'><span class='diff-marker'>+</span>"
     )
@@ -245,7 +245,7 @@ def render_single_diff(
 
     # Generate unified diff to identify changed lines
     differ = difflib.Differ()
-    diff: List[str] = list(differ.compare(old_lines, new_lines))
+    diff: list[str] = list(differ.compare(old_lines, new_lines))
 
     html_parts = ["<div class='edit-diff'>"]
 
@@ -257,7 +257,7 @@ def render_single_diff(
 
         if prefix == "- ":
             # Removed line - look ahead for corresponding addition
-            removed_lines: List[str] = [content]
+            removed_lines: list[str] = [content]
             j = i + 1
 
             # Collect consecutive removed lines
@@ -270,7 +270,7 @@ def render_single_diff(
                 j += 1
 
             # Collect consecutive added lines
-            added_lines: List[str] = []
+            added_lines: list[str] = []
             while j < len(diff) and diff[j].startswith("+ "):
                 added_lines.append(diff[j][2:])
                 j += 1
diff --git a/claude_code_log/html/templates/components/timeline.html b/claude_code_log/html/templates/components/timeline.html
index 7931efeb..9e09fbbb 100644
--- a/claude_code_log/html/templates/components/timeline.html
+++ b/claude_code_log/html/templates/components/timeline.html
@@ -29,7 +29,11 @@
             'thinking': { id: 'thinking', content: '💭 Thinking', style: 'background-color: #fce4ec;' },
             'system': { id: 'system', content: '⚙️ System', style: 'background-color: #ffeee1;' },
             'image': { id: 'image', content: '🖼️ Image', style: 'background-color: #e1f5fe;' },
-            'sidechain': { id: 'sidechain', content: '🔗 Sub-assistant', style: 'background-color: #f5f5f5;' }
+            'sidechain': { id: 'sidechain', content: '🔗 Sub-assistant', style: 'background-color: #f5f5f5;' },
+            'slash-command': { id: 'slash-command', content: '⌨️ Slash Command', style: 'background-color: #e8eaf6;' },
+            'command-output': { id: 'command-output', content: '📋 Command Output', style: 'background-color: #efebe9;' },
+            'bash-input': { id: 'bash-input', content: '💻 Bash Input', style: 'background-color: #e8eaf6;' },
+            'bash-output': { id: 'bash-output', content: '📄 Bash Output', style: 'background-color: #efebe9;' }
         };
 
         // Build timeline data from messages
@@ -55,6 +59,14 @@
                     messageType = 'sidechain';
                 } else if (classList.includes('system-warning') || classList.includes('system-error') || classList.includes('system-info')) {
                     messageType = 'system';
+                } else if (classList.includes('slash-command')) {
+                    messageType = 'slash-command';
+                } else if (classList.includes('command-output')) {
+                    messageType = 'command-output';
+                } else if (classList.includes('bash-input')) {
+                    messageType = 'bash-input';
+                } else if (classList.includes('bash-output')) {
+                    messageType = 'bash-output';
                 } else {
                     // Look for standard message types
                     messageType = classList.find(cls =>
@@ -179,10 +191,15 @@
             const activeTypes = Array.from(document.querySelectorAll('.filter-toggle.active'))
                 .map(toggle => toggle.dataset.type);
 
+            // Get all filter toggle types (to know which groups have filter controls)
+            const allFilterTypes = Array.from(document.querySelectorAll('.filter-toggle'))
+                .map(toggle => toggle.dataset.type);
+
             // Update groups visibility based on filter states
+            // Groups with filter toggles follow toggle state; groups without toggles stay visible
             const updatedGroups = groups.map(group => ({
                 ...group,
-                visible: activeTypes.includes(group.id)
+                visible: allFilterTypes.includes(group.id) ? activeTypes.includes(group.id) : true
             }));
 
             // Update timeline groups
@@ -260,7 +277,7 @@
                     axis: 2
                 },
                 groupOrder: (a, b) => {
-                    const order = ['user', 'assistant', 'sidechain', 'tool_use', 'tool_result', 'thinking', 'system', 'image'];
+                    const order = ['user', 'system', 'slash-command', 'command-output', 'bash-input', 'bash-output', 'thinking', 'assistant', 'sidechain', 'tool_use', 'tool_result', 'image'];
                     return order.indexOf(a.id) - order.indexOf(b.id);
                 }
             };
diff --git a/claude_code_log/html/templates/transcript.html b/claude_code_log/html/templates/transcript.html
index 8a256853..2f812bdf 100644
--- a/claude_code_log/html/templates/transcript.html
+++ b/claude_code_log/html/templates/transcript.html
@@ -272,7 +272,7 @@ <h3>🔍 Search & Filter</h3>
 
             // Count messages by type and update button labels
             function updateMessageCounts() {
-                const messageTypes = ['user', 'assistant', 'sidechain', 'system', 'thinking', 'image'];
+                const messageTypes = ['assistant', 'sidechain', 'system', 'thinking', 'image'];
 
                 messageTypes.forEach(type => {
                     const messages = document.querySelectorAll(`.message.${type}:not(.session-header)`);
@@ -292,8 +292,23 @@ <h3>🔍 Search & Filter</h3>
                     }
                 });
 
-                // Handle combined "tool" filter (tool_use + tool_result + bash messages)
-                const toolMessages = document.querySelectorAll(`.message.tool_use:not(.session-header), .message.tool_result:not(.session-header), .message.bash-input:not(.session-header), .message.bash-output:not(.session-header)`);
+                // Handle combined "user" filter (user + bash-input + bash-output)
+                const userMessages = document.querySelectorAll(`.message.user:not(.session-header), .message.bash-input:not(.session-header), .message.bash-output:not(.session-header)`);
+                const userCount = userMessages.length;
+                const userToggle = document.querySelector(`[data-type="user"]`);
+                const userCountSpan = userToggle ? userToggle.querySelector('.count') : null;
+
+                if (userCountSpan) {
+                    userCountSpan.textContent = `(${userCount})`;
+                    if (userCount === 0) {
+                        userToggle.style.display = 'none';
+                    } else {
+                        userToggle.style.display = 'flex';
+                    }
+                }
+
+                // Handle combined "tool" filter (tool_use + tool_result)
+                const toolMessages = document.querySelectorAll(`.message.tool_use:not(.session-header), .message.tool_result:not(.session-header)`);
                 const toolCount = toolMessages.length;
                 const toolToggle = document.querySelector(`[data-type="tool"]`);
                 const toolCountSpan = toolToggle ? toolToggle.querySelector('.count') : null;
@@ -314,11 +329,14 @@ <h3>🔍 Search & Filter</h3>
                     .filter(toggle => toggle.classList.contains('active'))
                     .map(toggle => toggle.dataset.type);
 
-                // Expand "tool" to include tool_use, tool_result, and bash messages
+                // Expand filter types to their corresponding CSS classes
                 const expandedTypes = [];
                 activeTypes.forEach(type => {
                     if (type === 'tool') {
-                        expandedTypes.push('tool_use', 'tool_result', 'bash-input', 'bash-output');
+                        expandedTypes.push('tool_use', 'tool_result');
+                    } else if (type === 'user') {
+                        // User filter includes bash commands (user-initiated)
+                        expandedTypes.push('user', 'bash-input', 'bash-output');
                     } else {
                         expandedTypes.push(type);
                     }
@@ -362,7 +380,7 @@ <h3>🔍 Search & Filter</h3>
             }
 
             function updateVisibleCounts() {
-                const messageTypes = ['user', 'assistant', 'sidechain', 'system', 'thinking', 'image'];
+                const messageTypes = ['assistant', 'sidechain', 'system', 'thinking', 'image'];
 
                 messageTypes.forEach(type => {
                     const visibleMessages = document.querySelectorAll(`.message.${type}:not(.session-header):not(.filtered-hidden)`);
@@ -389,9 +407,32 @@ <h3>🔍 Search & Filter</h3>
                     }
                 });
 
-                // Handle combined "tool" filter separately (includes bash messages)
-                const visibleToolMessages = document.querySelectorAll(`.message.tool_use:not(.session-header):not(.filtered-hidden), .message.tool_result:not(.session-header):not(.filtered-hidden), .message.bash-input:not(.session-header):not(.filtered-hidden), .message.bash-output:not(.session-header):not(.filtered-hidden)`);
-                const totalToolMessages = document.querySelectorAll(`.message.tool_use:not(.session-header), .message.tool_result:not(.session-header), .message.bash-input:not(.session-header), .message.bash-output:not(.session-header)`);
+                // Handle combined "user" filter separately (includes bash messages)
+                const visibleUserMessages = document.querySelectorAll(`.message.user:not(.session-header):not(.filtered-hidden), .message.bash-input:not(.session-header):not(.filtered-hidden), .message.bash-output:not(.session-header):not(.filtered-hidden)`);
+                const totalUserMessages = document.querySelectorAll(`.message.user:not(.session-header), .message.bash-input:not(.session-header), .message.bash-output:not(.session-header)`);
+                const visibleUserCount = visibleUserMessages.length;
+                const totalUserCount = totalUserMessages.length;
+
+                const userToggle = document.querySelector(`[data-type="user"]`);
+                const userCountSpan = userToggle ? userToggle.querySelector('.count') : null;
+
+                if (userCountSpan && totalUserCount > 0) {
+                    const activeTypes = Array.from(filterToggles)
+                        .filter(toggle => toggle.classList.contains('active'))
+                        .map(toggle => toggle.dataset.type);
+
+                    const isFiltering = activeTypes.length < filterToggles.length;
+
+                    if (isFiltering && visibleUserCount !== totalUserCount) {
+                        userCountSpan.textContent = `(${visibleUserCount}/${totalUserCount})`;
+                    } else {
+                        userCountSpan.textContent = `(${totalUserCount})`;
+                    }
+                }
+
+                // Handle combined "tool" filter separately
+                const visibleToolMessages = document.querySelectorAll(`.message.tool_use:not(.session-header):not(.filtered-hidden), .message.tool_result:not(.session-header):not(.filtered-hidden)`);
+                const totalToolMessages = document.querySelectorAll(`.message.tool_use:not(.session-header), .message.tool_result:not(.session-header)`);
                 const visibleToolCount = visibleToolMessages.length;
                 const totalToolCount = totalToolMessages.length;
 
diff --git a/claude_code_log/html/tool_formatters.py b/claude_code_log/html/tool_formatters.py
index 35053562..962a9f2f 100644
--- a/claude_code_log/html/tool_formatters.py
+++ b/claude_code_log/html/tool_formatters.py
@@ -14,9 +14,11 @@
 HTML for display in transcripts.
 """
 
+import base64
+import binascii
 import json
 import re
-from typing import Any, Dict, List, Optional, cast
+from typing import Any, Optional, cast
 
 from .utils import (
     escape_html,
@@ -48,7 +50,7 @@
 
 def _render_question_item(q: AskUserQuestionItem) -> str:
     """Render a single question item to HTML."""
-    html_parts: List[str] = ['<div class="question-block">']
+    html_parts: list[str] = ['<div class="question-block">']
 
     # Header (if present)
     if q.header:
@@ -89,7 +91,7 @@ def format_askuserquestion_content(ask_input: AskUserQuestionInput) -> str:
     options (with label and description), and multiSelect flag.
     """
     # Build list of questions from both formats
-    questions: List[AskUserQuestionItem] = list(ask_input.questions)
+    questions: list[AskUserQuestionItem] = list(ask_input.questions)
 
     # Handle single question format (legacy)
     if not questions and ask_input.question:
@@ -99,7 +101,7 @@ def format_askuserquestion_content(ask_input: AskUserQuestionInput) -> str:
         return '<div class="askuserquestion-content"><em>No question</em></div>'
 
     # Build HTML for all questions
-    html_parts: List[str] = ['<div class="askuserquestion-content">']
+    html_parts: list[str] = ['<div class="askuserquestion-content">']
     for q in questions:
         html_parts.append(_render_question_item(q))
     html_parts.append("</div>")  # Close askuserquestion-content
@@ -140,7 +142,7 @@ def format_askuserquestion_result(content: str) -> str:
         return ""
 
     # Build styled HTML
-    html_parts: List[str] = [
+    html_parts: list[str] = [
         '<div class="askuserquestion-content askuserquestion-result">'
     ]
 
@@ -217,7 +219,7 @@ def format_todowrite_content(todo_input: TodoWriteInput) -> str:
     status_emojis = {"pending": "⏳", "in_progress": "🔄", "completed": "✅"}
 
     # Build todo list HTML - todos are typed TodoWriteItem objects
-    todo_items: List[str] = []
+    todo_items: list[str] = []
     for todo in todo_input.todos:
         todo_id = escape_html(todo.id) if todo.id else ""
         content = escape_html(todo.content) if todo.content else ""
@@ -266,7 +268,7 @@ def format_read_tool_content(read_input: ReadInput) -> str:  # noqa: ARG001
 
 
 def _parse_cat_n_snippet(
-    lines: List[str], start_idx: int = 0
+    lines: list[str], start_idx: int = 0
 ) -> Optional[tuple[str, Optional[str], int]]:
     """Parse cat-n formatted snippet from lines.
 
@@ -277,7 +279,7 @@ def _parse_cat_n_snippet(
     Returns:
         Tuple of (code_content, system_reminder, line_offset) or None if not parseable
     """
-    code_lines: List[str] = []
+    code_lines: list[str] = []
     system_reminder: Optional[str] = None
     in_system_reminder = False
     line_offset = 1  # Default offset
@@ -631,7 +633,7 @@ def format_tool_use_title(tool_use: ToolUseContent) -> str:
 # -- Generic Parameter Table --------------------------------------------------
 
 
-def render_params_table(params: Dict[str, Any]) -> str:
+def render_params_table(params: dict[str, Any]) -> str:
     """Render a dictionary of parameters as an HTML table.
 
     Reusable for tool parameters, diagnostic objects, etc.
@@ -788,11 +790,11 @@ def format_tool_result_content(
     if isinstance(tool_result.content, str):
         raw_content = tool_result.content
         has_images = False
-        image_html_parts: List[str] = []
+        image_html_parts: list[str] = []
     else:
         # Content is a list of structured items, extract text and images
-        content_parts: List[str] = []
-        image_html_parts: List[str] = []
+        content_parts: list[str] = []
+        image_html_parts: list[str] = []
         for item in tool_result.content:
             item_type = item.get("type")
             if item_type == "text":
@@ -801,14 +803,28 @@ def format_tool_result_content(
                     content_parts.append(text_value)
             elif item_type == "image":
                 # Handle image content within tool results
-                source = cast(Dict[str, Any], item.get("source", {}))
+                source = cast(dict[str, Any], item.get("source", {}))
                 if source:
                     media_type: str = str(source.get("media_type", "image/png"))
+                    # Restrict to safe image types to prevent XSS via SVG
+                    allowed_media_types = {
+                        "image/png",
+                        "image/jpeg",
+                        "image/gif",
+                        "image/webp",
+                    }
+                    if media_type not in allowed_media_types:
+                        continue
                     data: str = str(source.get("data", ""))
                     if data:
+                        # Validate base64 data to prevent corruption/injection
+                        try:
+                            base64.b64decode(data, validate=True)
+                        except (binascii.Error, ValueError):
+                            continue
                         data_url = f"data:{media_type};base64,{data}"
                         image_html_parts.append(
-                            f'<img src="{data_url}" alt="Tool result image" '
+                            f'<img src="{escape_html(data_url)}" alt="Tool result image" '
                             f'class="tool-result-image" />'
                         )
         raw_content = "\n".join(content_parts)
@@ -868,15 +884,21 @@ def format_tool_result_content(
 
     # Check if this looks like Bash tool output and process ANSI codes
     # Bash tool results often contain ANSI escape sequences and terminal output
-    if _looks_like_bash_output(raw_content):
-        escaped_content = convert_ansi_to_html(raw_content)
-    else:
-        escaped_content = escape_html(raw_content)
+    is_ansi = _looks_like_bash_output(raw_content)
+    full_html = (
+        convert_ansi_to_html(raw_content) if is_ansi else escape_html(raw_content)
+    )
+    # For preview, always use plain escaped text (don't truncate HTML with tags)
+    preview_html = (
+        escape_html(raw_content[:200]) + "..."
+        if len(raw_content) > 200
+        else escape_html(raw_content)
+    )
 
     # Build final HTML based on content length and presence of images
     if has_images:
         # Combine text and images
-        text_html = f"<pre>{escaped_content}</pre>" if escaped_content else ""
+        text_html = f"<pre>{full_html}</pre>" if full_html else ""
         images_html = "".join(image_html_parts)
         combined_content = f"{text_html}{images_html}"
 
@@ -895,18 +917,17 @@ def format_tool_result_content(
     else:
         # Text-only content (existing behavior)
         # For simple content, show directly without collapsible wrapper
-        if len(escaped_content) <= 200:
-            return f"<pre>{escaped_content}</pre>"
+        if len(raw_content) <= 200:
+            return f"<pre>{full_html}</pre>"
 
         # For longer content, use collapsible details but no extra wrapper
-        preview_text = escaped_content[:200] + "..."
         return f"""
     <details class="collapsible-details">
         <summary>
-            <div class="preview-content"><pre>{preview_text}</pre></div>
+            <div class="preview-content"><pre>{preview_html}</pre></div>
         </summary>
         <div class="details-content">
-            <pre>{escaped_content}</pre>
+            <pre>{full_html}</pre>
         </div>
     </details>
     """
diff --git a/claude_code_log/html/user_formatters.py b/claude_code_log/html/user_formatters.py
index 21528208..b89b329d 100644
--- a/claude_code_log/html/user_formatters.py
+++ b/claude_code_log/html/user_formatters.py
@@ -8,10 +8,6 @@
 - tool_formatters.py: tool use/result content
 """
 
-from typing import List
-
-import mistune
-
 from .ansi_colors import convert_ansi_to_html
 from ..models import (
     BashInputContent,
@@ -52,7 +48,7 @@ def format_slash_command_content(content: SlashCommandContent) -> str:
     escaped_command_contents = escape_html(formatted_contents)
 
     # Build the content HTML - command name is the primary content
-    content_parts: List[str] = [f"<code>{escaped_command_name}</code>"]
+    content_parts: list[str] = [f"<code>{escaped_command_name}</code>"]
     if content.command_args:
         content_parts.append(f"<strong>Args:</strong> {escaped_command_args}")
     if content.command_contents:
@@ -64,8 +60,8 @@ def format_slash_command_content(content: SlashCommandContent) -> str:
                 f"<strong>Content:</strong><pre>{escaped_command_contents}</pre>"
             )
         else:
-            # Long content, make collapsible
-            preview = "\n".join(lines[:5])
+            # Long content, make collapsible with truncation indicator
+            preview = "\n".join(lines[:5]) + "\n..."
             collapsible = render_collapsible_code(
                 f"<pre>{preview}</pre>",
                 f"<pre>{escaped_command_contents}</pre>",
@@ -87,9 +83,10 @@ def format_command_output_content(content: CommandOutputContent) -> str:
         HTML string for the command output display
     """
     if content.is_markdown:
-        # Render as markdown
-        markdown_html = mistune.html(content.stdout)
-        return f"<div class='command-output-content'>{markdown_html}</div>"
+        # Render as markdown using shared renderer for GFM plugins and syntax highlighting
+        return render_markdown_collapsible(
+            content.stdout, "command-output-content", line_threshold=20
+        )
     else:
         # Convert ANSI codes to HTML for colored display
         html_content = convert_ansi_to_html(content.stdout)
@@ -128,18 +125,18 @@ def format_bash_output_content(
     Returns:
         HTML string for the bash output display
     """
-    output_parts: List[tuple[str, str, int, str]] = []
+    output_parts: list[tuple[str, str, int, str]] = []
     total_lines = 0
 
     if content.stdout:
         escaped_stdout = convert_ansi_to_html(content.stdout)
-        stdout_lines = content.stdout.count("\n") + 1
+        stdout_lines = len(content.stdout.splitlines())
         total_lines += stdout_lines
         output_parts.append(("stdout", escaped_stdout, stdout_lines, content.stdout))
 
     if content.stderr:
         escaped_stderr = convert_ansi_to_html(content.stderr)
-        stderr_lines = content.stderr.count("\n") + 1
+        stderr_lines = len(content.stderr.splitlines())
         total_lines += stderr_lines
         output_parts.append(("stderr", escaped_stderr, stderr_lines, content.stderr))
 
@@ -150,7 +147,7 @@ def format_bash_output_content(
         )
 
     # Build the HTML parts
-    html_parts: List[str] = []
+    html_parts: list[str] = []
     for output_type, escaped_content, _, _ in output_parts:
         css_name = f"bash-{output_type}"
         html_parts.append(f"<pre class='{css_name}'>{escaped_content}</pre>")
@@ -166,13 +163,12 @@ def format_bash_output_content(
         if total_lines > preview_lines:
             preview_html += "\n..."
 
-        return f"""<details class='collapsible-code'>
-            <summary>
-                <span class='line-count'>{total_lines} lines</span>
-                <pre class='preview-content bash-stdout'>{preview_html}</pre>
-            </summary>
-            <div class='code-full'>{full_html}</div>
-        </details>"""
+        # Use render_collapsible_code for consistent collapse markup
+        return render_collapsible_code(
+            preview_html=f"<pre class='bash-stdout'>{preview_html}</pre>",
+            full_html=full_html,
+            line_count=total_lines,
+        )
 
     return full_html
 
@@ -205,7 +201,7 @@ def format_user_text_model_content(content: UserTextContent) -> str:
     Returns:
         HTML string combining IDE notifications and main text content
     """
-    parts: List[str] = []
+    parts: list[str] = []
 
     # Add IDE notifications first if present
     if content.ide_notifications:
@@ -280,21 +276,21 @@ def _format_selection(selection: IdeSelection) -> str:
     # For large selections, make them collapsible
     if len(selection.content) > 200:
         preview = escape_html(selection.content[:150]) + "..."
-        return f"""
-            <div class='ide-notification ide-selection'>
-                <details class='ide-selection-collapsible'>
-                    <summary>📝 {preview}</summary>
-                    <pre class='ide-selection-content'>{escaped_content}</pre>
-                </details>
-            </div>
-        """
+        return (
+            f"<div class='ide-notification ide-selection'>"
+            f"<details class='ide-selection-collapsible'>"
+            f"<summary>📝 {preview}</summary>"
+            f"<pre class='ide-selection-content'>{escaped_content}</pre>"
+            f"</details>"
+            f"</div>"
+        )
     else:
         return f"<div class='ide-notification ide-selection'>📝 {escaped_content}</div>"
 
 
-def _format_diagnostic(diagnostic: IdeDiagnostic) -> List[str]:
+def _format_diagnostic(diagnostic: IdeDiagnostic) -> list[str]:
     """Format a single IDE diagnostic as HTML (may produce multiple notifications)."""
-    notifications: List[str] = []
+    notifications: list[str] = []
 
     if diagnostic.diagnostics:
         # Parsed JSON diagnostics - render each as a table
@@ -308,17 +304,19 @@ def _format_diagnostic(diagnostic: IdeDiagnostic) -> List[str]:
             notifications.append(notification_html)
     elif diagnostic.raw_content:
         # JSON parsing failed, render as plain text
+        is_truncated = len(diagnostic.raw_content) > 200
         escaped_content = escape_html(diagnostic.raw_content[:200])
+        truncation_marker = "..." if is_truncated else ""
         notification_html = (
             f"<div class='ide-notification'>🤖 IDE Diagnostics (parse error)<br>"
-            f"<pre>{escaped_content}...</pre></div>"
+            f"<pre>{escaped_content}{truncation_marker}</pre></div>"
         )
         notifications.append(notification_html)
 
     return notifications
 
 
-def format_ide_notification_content(content: IdeNotificationContent) -> List[str]:
+def format_ide_notification_content(content: IdeNotificationContent) -> list[str]:
     """Format IDE notification content as HTML.
 
     Takes structured IdeNotificationContent and returns a list of HTML
@@ -330,7 +328,7 @@ def format_ide_notification_content(content: IdeNotificationContent) -> List[str
     Returns:
         List of HTML notification strings
     """
-    notifications: List[str] = []
+    notifications: list[str] = []
 
     # Format opened files
     for opened_file in content.opened_files:
diff --git a/claude_code_log/html/utils.py b/claude_code_log/html/utils.py
index fdd8c379..8a99edbb 100644
--- a/claude_code_log/html/utils.py
+++ b/claude_code_log/html/utils.py
@@ -13,6 +13,7 @@
 HTML-specific output.
 """
 
+import functools
 import html
 from pathlib import Path
 from typing import Any, Optional, TYPE_CHECKING
@@ -83,8 +84,15 @@ def get_message_emoji(msg: "TemplateMessage") -> str:
     if msg_type == "session_header":
         return "📋"
     elif msg_type == "user":
+        # Command output has no emoji (neutral - can be from built-in or user command)
+        if msg.modifiers.is_command_output:
+            return ""
+        return "🤷"
+    elif msg_type == "bash-input":
         return "🤷"
     elif msg_type == "assistant":
+        if msg.modifiers.is_sidechain:
+            return "🔗"
         return "🤖"
     elif msg_type == "system":
         return "⚙️"
@@ -131,7 +139,7 @@ def block_code(code: str, info: Optional[str] = None) -> str:
                 # Language hint provided, use Pygments
                 lang = info.split()[0] if info else ""
                 try:
-                    lexer = get_lexer_by_name(lang, stripall=True)  # type: ignore[reportUnknownVariableType]
+                    lexer = get_lexer_by_name(lang, stripall=False)  # type: ignore[reportUnknownVariableType]
                 except ClassNotFound:
                     lexer = TextLexer()  # type: ignore[reportUnknownVariableType]
 
@@ -152,24 +160,29 @@ def block_code(code: str, info: Optional[str] = None) -> str:
     return plugin_pygments
 
 
+@functools.lru_cache(maxsize=1)
+def _get_markdown_renderer() -> mistune.Markdown:
+    """Get cached Mistune markdown renderer with Pygments syntax highlighting."""
+    return mistune.create_markdown(
+        plugins=[
+            "strikethrough",
+            "footnotes",
+            "table",
+            "url",
+            "task_lists",
+            "def_list",
+            _create_pygments_plugin(),
+        ],
+        escape=False,  # Don't escape HTML since we want to render markdown properly
+        hard_wrap=True,  # Line break for newlines (checklists in Assistant messages)
+    )
+
+
 def render_markdown(text: str) -> str:
     """Convert markdown text to HTML using mistune with Pygments syntax highlighting."""
     # Track markdown rendering time if enabled
     with timing_stat("_markdown_timings"):
-        # Configure mistune with GitHub-flavored markdown features
-        renderer = mistune.create_markdown(
-            plugins=[
-                "strikethrough",
-                "footnotes",
-                "table",
-                "url",
-                "task_lists",
-                "def_list",
-                _create_pygments_plugin(),
-            ],
-            escape=False,  # Don't escape HTML since we want to render markdown properly
-            hard_wrap=True,  # Line break for newlines (checklists in Assistant messages)
-        )
+        renderer = _get_markdown_renderer()
         return str(renderer(text))
 
 
@@ -281,7 +294,7 @@ def render_file_content_collapsible(
 
     html_parts = [f"<div class='{css_class}'>"]
 
-    lines = code_content.split("\n")
+    lines = code_content.splitlines()
     if len(lines) > line_threshold:
         # Extract preview from already-highlighted HTML (avoids double highlighting)
         preview_html = truncate_highlighted_preview(
@@ -331,8 +344,9 @@ def starts_with_emoji(text: str) -> bool:
     )
 
 
+@functools.lru_cache(maxsize=1)
 def get_template_environment() -> Environment:
-    """Get Jinja2 template environment for HTML rendering.
+    """Get cached Jinja2 template environment for HTML rendering.
 
     Creates a Jinja2 environment configured with:
     - Template loading from the templates directory
@@ -340,7 +354,7 @@ def get_template_environment() -> Environment:
     - Custom template filters/functions (starts_with_emoji)
 
     Returns:
-        Configured Jinja2 Environment
+        Configured Jinja2 Environment (cached after first call)
     """
     templates_dir = Path(__file__).parent / "templates"
     env = Environment(
diff --git a/claude_code_log/models.py b/claude_code_log/models.py
index 135983e1..eaf3315f 100644
--- a/claude_code_log/models.py
+++ b/claude_code_log/models.py
@@ -5,13 +5,13 @@
 
 from dataclasses import dataclass
 from enum import Enum
-from typing import Any, List, Union, Optional, Dict, Literal
+from typing import Any, Union, Optional, Literal
 
 from anthropic.types import Message as AnthropicMessage
 from anthropic.types import StopReason
 from anthropic.types import Usage as AnthropicUsage
 from anthropic.types.content_block import ContentBlock
-from pydantic import BaseModel
+from pydantic import BaseModel, PrivateAttr
 
 
 class MessageType(str, Enum):
@@ -122,8 +122,8 @@ class HookSummaryContent(MessageContent):
     """
 
     has_output: bool
-    hook_errors: List[str]  # Error messages from hooks
-    hook_infos: List[HookInfo]  # Info about each hook executed
+    hook_errors: list[str]  # Error messages from hooks
+    hook_infos: list[HookInfo]  # Info about each hook executed
 
 
 # =============================================================================
@@ -187,7 +187,7 @@ class ToolResultContentModel(MessageContent):
     """
 
     tool_use_id: str
-    content: Any  # Union[str, List[Dict[str, Any]]]
+    content: Any  # Union[str, list[dict[str, Any]]]
     is_error: bool = False
     tool_name: Optional[str] = None  # Name of the tool that produced this result
     file_path: Optional[str] = None  # File path for Read/Edit/Write tools
@@ -239,7 +239,7 @@ class IdeDiagnostic:
     Contains either parsed JSON diagnostics or raw content if parsing failed.
     """
 
-    diagnostics: Optional[List[Dict[str, Any]]] = None  # Parsed diagnostic objects
+    diagnostics: Optional[list[dict[str, Any]]] = None  # Parsed diagnostic objects
     raw_content: Optional[str] = None  # Fallback if JSON parsing failed
 
 
@@ -255,9 +255,9 @@ class IdeNotificationContent(MessageContent):
     Format-neutral: stores structured data, not HTML.
     """
 
-    opened_files: List[IdeOpenedFile]
-    selections: List[IdeSelection]
-    diagnostics: List[IdeDiagnostic]
+    opened_files: list[IdeOpenedFile]
+    selections: list[IdeSelection]
+    diagnostics: list[IdeDiagnostic]
     remaining_text: str  # Text after notifications extracted
 
 
@@ -379,7 +379,7 @@ class EditOutput(MessageContent):
 
     file_path: str
     success: bool
-    diffs: List[EditDiff]  # Changes made
+    diffs: list[EditDiff]  # Changes made
     message: str  # Result message or code snippet
     start_line: int = 1  # Starting line number for code display
 
@@ -424,7 +424,7 @@ class GlobOutput(MessageContent):
     """
 
     pattern: str
-    files: List[str]  # Matching file paths
+    files: list[str]  # Matching file paths
     truncated: bool  # Whether list was truncated
 
 
@@ -438,7 +438,7 @@ class GrepOutput(MessageContent):
     """
 
     pattern: str
-    matches: List[str]  # Matching lines/files
+    matches: list[str]  # Matching lines/files
     output_mode: str  # "content", "files_with_matches", or "count"
     truncated: bool
 
@@ -526,7 +526,7 @@ class MultiEditInput(BaseModel):
     """Input parameters for the MultiEdit tool."""
 
     file_path: str
-    edits: List[EditItem]
+    edits: list[EditItem]
 
 
 class GlobInput(BaseModel):
@@ -581,7 +581,7 @@ class TodoWriteItem(BaseModel):
 class TodoWriteInput(BaseModel):
     """Input parameters for the TodoWrite tool."""
 
-    todos: List[TodoWriteItem]
+    todos: list[TodoWriteItem]
 
 
 class AskUserQuestionOption(BaseModel):
@@ -602,7 +602,7 @@ class AskUserQuestionItem(BaseModel):
 
     question: str = ""
     header: Optional[str] = None
-    options: List[AskUserQuestionOption] = []
+    options: list[AskUserQuestionOption] = []
     multiSelect: bool = False
 
 
@@ -612,7 +612,7 @@ class AskUserQuestionInput(BaseModel):
     Supports both modern format (questions list) and legacy format (single question).
     """
 
-    questions: List[AskUserQuestionItem] = []
+    questions: list[AskUserQuestionItem] = []
     question: Optional[str] = None  # Legacy single question format
 
 
@@ -637,7 +637,7 @@ class ExitPlanModeInput(BaseModel):
     TodoWriteInput,
     AskUserQuestionInput,
     ExitPlanModeInput,
-    Dict[str, Any],  # Fallback for unknown tools
+    dict[str, Any],  # Fallback for unknown tools
 ]
 
 
@@ -649,7 +649,7 @@ class UsageInfo(BaseModel):
     cache_read_input_tokens: Optional[int] = None
     output_tokens: Optional[int] = None
     service_tier: Optional[str] = None
-    server_tool_use: Optional[Dict[str, Any]] = None
+    server_tool_use: Optional[dict[str, Any]] = None
 
     def to_anthropic_usage(self) -> Optional[AnthropicUsage]:
         """Convert to Anthropic Usage type if both required fields are present."""
@@ -688,8 +688,10 @@ class ToolUseContent(BaseModel, MessageContent):
     type: Literal["tool_use"]
     id: str
     name: str
-    input: Dict[str, Any]
-    _parsed_input: Optional["ToolInput"] = None  # Cached parsed input
+    input: dict[str, Any]
+    _parsed_input: Optional["ToolInput"] = PrivateAttr(
+        default=None
+    )  # Cached parsed input
 
     @property
     def parsed_input(self) -> "ToolInput":
@@ -711,7 +713,7 @@ def parsed_input(self) -> "ToolInput":
 class ToolResultContent(BaseModel):
     type: Literal["tool_result"]
     tool_use_id: str
-    content: Union[str, List[Dict[str, Any]]]
+    content: Union[str, list[dict[str, Any]]]
     is_error: Optional[bool] = None
     agentId: Optional[str] = None  # Reference to agent file for sub-agent messages
 
@@ -746,7 +748,7 @@ class ImageContent(BaseModel, MessageContent):
 
 class UserMessage(BaseModel):
     role: Literal["user"]
-    content: Union[str, List[ContentItem]]
+    content: list[ContentItem]
     usage: Optional["UsageInfo"] = None  # For type compatibility with AssistantMessage
 
 
@@ -757,7 +759,7 @@ class AssistantMessage(BaseModel):
     type: Literal["message"]
     role: Literal["assistant"]
     model: str
-    content: List[ContentItem]
+    content: list[ContentItem]
     stop_reason: Optional[StopReason] = None
     stop_sequence: Optional[str] = None
     usage: Optional[UsageInfo] = None
@@ -789,8 +791,8 @@ def from_anthropic_message(
 # ReadOutput, EditOutput, etc. (see Tool Output Content Models section)
 ToolUseResult = Union[
     str,
-    List[Any],  # Covers List[TodoWriteItem], List[ContentItem], etc.
-    Dict[str, Any],  # Covers structured results
+    list[Any],  # Covers list[TodoWriteItem], list[ContentItem], etc.
+    dict[str, Any],  # Covers structured results
 ]
 
 
@@ -837,8 +839,8 @@ class SystemTranscriptEntry(BaseTranscriptEntry):
     level: Optional[str] = None  # e.g., "warning", "info", "error"
     # Hook summary fields (for subtype="stop_hook_summary")
     hasOutput: Optional[bool] = None
-    hookErrors: Optional[List[str]] = None
-    hookInfos: Optional[List[Dict[str, Any]]] = None
+    hookErrors: Optional[list[str]] = None
+    hookInfos: Optional[list[dict[str, Any]]] = None
     preventedContinuation: Optional[bool] = None
 
 
@@ -857,7 +859,7 @@ class QueueOperationTranscriptEntry(BaseModel):
     operation: Literal["enqueue", "dequeue", "remove", "popAll"]
     timestamp: str
     sessionId: str
-    content: Optional[Union[List[ContentItem], str]] = (
+    content: Optional[Union[list[ContentItem], str]] = (
         None  # List for enqueue, str for remove/popAll
     )
 
diff --git a/claude_code_log/parser.py b/claude_code_log/parser.py
index 23266d3d..89ead392 100644
--- a/claude_code_log/parser.py
+++ b/claude_code_log/parser.py
@@ -3,7 +3,7 @@
 
 import json
 import re
-from typing import Any, Callable, Dict, List, Optional, Union, cast, TypeGuard
+from typing import Any, Callable, Optional, Union, cast, TypeGuard
 from datetime import datetime
 
 from anthropic.types import Message as AnthropicMessage
@@ -61,26 +61,23 @@
 )
 
 
-def extract_text_content(content: Union[str, List[ContentItem], None]) -> str:
+def extract_text_content(content: Optional[list[ContentItem]]) -> str:
     """Extract text content from Claude message content structure.
 
     Supports both custom models (TextContent, ThinkingContent) and official
     Anthropic SDK types (TextBlock, ThinkingBlock).
     """
-    if content is None:
+    if not content:
         return ""
-    if isinstance(content, list):
-        text_parts: List[str] = []
-        for item in content:
-            # Handle text content (custom TextContent or Anthropic TextBlock)
-            if isinstance(item, (TextContent, TextBlock)):
-                text_parts.append(item.text)
-            # Skip thinking content (custom ThinkingContent or Anthropic ThinkingBlock)
-            elif isinstance(item, (ThinkingContent, ThinkingBlock)):
-                continue
-        return "\n".join(text_parts)
-    else:
-        return str(content) if content else ""
+    text_parts: list[str] = []
+    for item in content:
+        # Handle text content (custom TextContent or Anthropic TextBlock)
+        if isinstance(item, (TextContent, TextBlock)):
+            text_parts.append(item.text)
+        # Skip thinking content (custom ThinkingContent or Anthropic ThinkingBlock)
+        elif isinstance(item, (ThinkingContent, ThinkingBlock)):
+            continue
+    return "\n".join(text_parts)
 
 
 def parse_timestamp(timestamp_str: str) -> Optional[datetime]:
@@ -125,7 +122,7 @@ def parse_slash_command(text: str) -> Optional[SlashCommandContent]:
         try:
             contents_json: Any = json.loads(contents_text)
             if isinstance(contents_json, dict) and "text" in contents_json:
-                text_dict = cast(Dict[str, Any], contents_json)
+                text_dict = cast(dict[str, Any], contents_json)
                 text_value = text_dict["text"]
                 command_contents = str(text_value)
             else:
@@ -232,9 +229,9 @@ def parse_ide_notifications(text: str) -> Optional[IdeNotificationContent]:
     Returns:
         IdeNotificationContent if any tags found, None otherwise
     """
-    opened_files: List[IdeOpenedFile] = []
-    selections: List[IdeSelection] = []
-    diagnostics: List[IdeDiagnostic] = []
+    opened_files: list[IdeOpenedFile] = []
+    selections: list[IdeSelection] = []
+    diagnostics: list[IdeDiagnostic] = []
     remaining_text = text
 
     # Pattern 1: <ide_opened_file>content</ide_opened_file>
@@ -259,7 +256,7 @@ def parse_ide_notifications(text: str) -> Optional[IdeNotificationContent]:
             if isinstance(parsed_diagnostics, list):
                 diagnostics.append(
                     IdeDiagnostic(
-                        diagnostics=cast(List[Dict[str, Any]], parsed_diagnostics)
+                        diagnostics=cast(list[dict[str, Any]], parsed_diagnostics)
                     )
                 )
             else:
@@ -288,7 +285,7 @@ def parse_ide_notifications(text: str) -> Optional[IdeNotificationContent]:
 
 
 def parse_compacted_summary(
-    content_list: List[ContentItem],
+    content_list: list[ContentItem],
 ) -> Optional[CompactedSummaryContent]:
     """Parse compacted session summary from content list.
 
@@ -351,7 +348,7 @@ def parse_user_memory(text: str) -> Optional[UserMemoryContent]:
 
 
 def parse_user_message_content(
-    content_list: List[ContentItem],
+    content_list: list[ContentItem],
 ) -> Optional[UserMessageContent]:
     """Parse user message content into a structured content model.
 
@@ -443,7 +440,7 @@ def is_bash_output(text_content: str) -> bool:
     return "<bash-stdout>" in text_content or "<bash-stderr>" in text_content
 
 
-def is_warmup_only_session(messages: List[TranscriptEntry], session_id: str) -> bool:
+def is_warmup_only_session(messages: list[TranscriptEntry], session_id: str) -> bool:
     """Check if a session contains only warmup user messages.
 
     A warmup session is one where ALL user messages are literally just "Warmup".
@@ -456,7 +453,7 @@ def is_warmup_only_session(messages: List[TranscriptEntry], session_id: str) ->
     Returns:
         True if ALL user messages in the session are "Warmup", False otherwise
     """
-    user_messages_in_session: List[str] = []
+    user_messages_in_session: list[str] = []
 
     for message in messages:
         if (
@@ -494,7 +491,7 @@ def is_assistant_entry(entry: TranscriptEntry) -> TypeGuard[AssistantTranscriptE
 # Tool Input Parsing
 # =============================================================================
 
-TOOL_INPUT_MODELS: Dict[str, type[BaseModel]] = {
+TOOL_INPUT_MODELS: dict[str, type[BaseModel]] = {
     "Bash": BashInput,
     "Read": ReadInput,
     "Write": WriteInput,
@@ -515,10 +512,10 @@ def is_assistant_entry(entry: TranscriptEntry) -> TypeGuard[AssistantTranscriptE
 # They use defaults for missing fields and skip invalid nested items.
 
 
-def _parse_todowrite_lenient(data: Dict[str, Any]) -> TodoWriteInput:
+def _parse_todowrite_lenient(data: dict[str, Any]) -> TodoWriteInput:
     """Parse TodoWrite input leniently, handling malformed data."""
     todos_raw = data.get("todos", [])
-    valid_todos: List[TodoWriteItem] = []
+    valid_todos: list[TodoWriteItem] = []
     for item in todos_raw:
         if isinstance(item, dict):
             try:
@@ -530,7 +527,7 @@ def _parse_todowrite_lenient(data: Dict[str, Any]) -> TodoWriteInput:
     return TodoWriteInput(todos=valid_todos)
 
 
-def _parse_bash_lenient(data: Dict[str, Any]) -> BashInput:
+def _parse_bash_lenient(data: dict[str, Any]) -> BashInput:
     """Parse Bash input leniently."""
     return BashInput(
         command=data.get("command", ""),
@@ -540,7 +537,7 @@ def _parse_bash_lenient(data: Dict[str, Any]) -> BashInput:
     )
 
 
-def _parse_write_lenient(data: Dict[str, Any]) -> WriteInput:
+def _parse_write_lenient(data: dict[str, Any]) -> WriteInput:
     """Parse Write input leniently."""
     return WriteInput(
         file_path=data.get("file_path", ""),
@@ -548,7 +545,7 @@ def _parse_write_lenient(data: Dict[str, Any]) -> WriteInput:
     )
 
 
-def _parse_edit_lenient(data: Dict[str, Any]) -> EditInput:
+def _parse_edit_lenient(data: dict[str, Any]) -> EditInput:
     """Parse Edit input leniently."""
     return EditInput(
         file_path=data.get("file_path", ""),
@@ -558,10 +555,10 @@ def _parse_edit_lenient(data: Dict[str, Any]) -> EditInput:
     )
 
 
-def _parse_multiedit_lenient(data: Dict[str, Any]) -> MultiEditInput:
+def _parse_multiedit_lenient(data: dict[str, Any]) -> MultiEditInput:
     """Parse Multiedit input leniently."""
     edits_raw = data.get("edits", [])
-    valid_edits: List[EditItem] = []
+    valid_edits: list[EditItem] = []
     for edit in edits_raw:
         if isinstance(edit, dict):
             try:
@@ -571,7 +568,7 @@ def _parse_multiedit_lenient(data: Dict[str, Any]) -> MultiEditInput:
     return MultiEditInput(file_path=data.get("file_path", ""), edits=valid_edits)
 
 
-def _parse_task_lenient(data: Dict[str, Any]) -> TaskInput:
+def _parse_task_lenient(data: dict[str, Any]) -> TaskInput:
     """Parse Task input leniently."""
     return TaskInput(
         prompt=data.get("prompt", ""),
@@ -583,7 +580,7 @@ def _parse_task_lenient(data: Dict[str, Any]) -> TaskInput:
     )
 
 
-def _parse_read_lenient(data: Dict[str, Any]) -> ReadInput:
+def _parse_read_lenient(data: dict[str, Any]) -> ReadInput:
     """Parse Read input leniently."""
     return ReadInput(
         file_path=data.get("file_path", ""),
@@ -592,17 +589,17 @@ def _parse_read_lenient(data: Dict[str, Any]) -> ReadInput:
     )
 
 
-def _parse_askuserquestion_lenient(data: Dict[str, Any]) -> AskUserQuestionInput:
+def _parse_askuserquestion_lenient(data: dict[str, Any]) -> AskUserQuestionInput:
     """Parse AskUserQuestion input leniently, handling malformed data."""
     questions_raw = data.get("questions", [])
-    valid_questions: List[AskUserQuestionItem] = []
+    valid_questions: list[AskUserQuestionItem] = []
     for q in questions_raw:
         if isinstance(q, dict):
-            q_dict = cast(Dict[str, Any], q)
+            q_dict = cast(dict[str, Any], q)
             try:
                 # Parse options leniently
                 options_raw = q_dict.get("options", [])
-                valid_options: List[AskUserQuestionOption] = []
+                valid_options: list[AskUserQuestionOption] = []
                 for opt in options_raw:
                     if isinstance(opt, dict):
                         try:
@@ -627,7 +624,7 @@ def _parse_askuserquestion_lenient(data: Dict[str, Any]) -> AskUserQuestionInput
     )
 
 
-def _parse_exitplanmode_lenient(data: Dict[str, Any]) -> ExitPlanModeInput:
+def _parse_exitplanmode_lenient(data: dict[str, Any]) -> ExitPlanModeInput:
     """Parse ExitPlanMode input leniently."""
     return ExitPlanModeInput(
         plan=data.get("plan", ""),
@@ -637,7 +634,7 @@ def _parse_exitplanmode_lenient(data: Dict[str, Any]) -> ExitPlanModeInput:
 
 
 # Mapping of tool names to their lenient parsers
-TOOL_LENIENT_PARSERS: Dict[str, Any] = {
+TOOL_LENIENT_PARSERS: dict[str, Any] = {
     "Bash": _parse_bash_lenient,
     "Write": _parse_write_lenient,
     "Edit": _parse_edit_lenient,
@@ -651,7 +648,7 @@ def _parse_exitplanmode_lenient(data: Dict[str, Any]) -> ExitPlanModeInput:
 }
 
 
-def parse_tool_input(tool_name: str, input_data: Dict[str, Any]) -> ToolInput:
+def parse_tool_input(tool_name: str, input_data: dict[str, Any]) -> ToolInput:
     """Parse tool input dictionary into a typed model.
 
     Uses strict validation first, then lenient parsing if available.
@@ -729,7 +726,7 @@ def normalize_usage_info(usage_data: Any) -> Optional[UsageInfo]:
 # to clarify which content types can appear in which context.
 
 
-def _parse_text_content(item_data: Dict[str, Any]) -> ContentItem:
+def _parse_text_content(item_data: dict[str, Any]) -> ContentItem:
     """Parse text content, trying Anthropic types first.
 
     Common to both user and assistant messages.
@@ -740,7 +737,7 @@ def _parse_text_content(item_data: Dict[str, Any]) -> ContentItem:
         return TextContent.model_validate(item_data)
 
 
-def parse_user_content_item(item_data: Dict[str, Any]) -> ContentItem:
+def parse_user_content_item(item_data: dict[str, Any]) -> ContentItem:
     """Parse a content item from a UserTranscriptEntry.
 
     User messages can contain:
@@ -764,7 +761,7 @@ def parse_user_content_item(item_data: Dict[str, Any]) -> ContentItem:
         return TextContent(type="text", text=str(item_data))
 
 
-def parse_assistant_content_item(item_data: Dict[str, Any]) -> ContentItem:
+def parse_assistant_content_item(item_data: dict[str, Any]) -> ContentItem:
     """Parse a content item from an AssistantTranscriptEntry.
 
     Assistant messages can contain:
@@ -798,7 +795,7 @@ def parse_assistant_content_item(item_data: Dict[str, Any]) -> ContentItem:
         return TextContent(type="text", text=str(item_data))
 
 
-def parse_content_item(item_data: Dict[str, Any]) -> ContentItem:
+def parse_content_item(item_data: dict[str, Any]) -> ContentItem:
     """Parse a content item (generic fallback).
 
     For cases where the entry type is unknown. Handles all content types.
@@ -842,9 +839,12 @@ def parse_content_item(item_data: Dict[str, Any]) -> ContentItem:
 
 def parse_message_content(
     content_data: Any,
-    item_parser: Callable[[Dict[str, Any]], ContentItem] = parse_content_item,
-) -> Union[str, List[ContentItem]]:
-    """Parse message content, handling both string and list formats.
+    item_parser: Callable[[dict[str, Any]], ContentItem] = parse_content_item,
+) -> list[ContentItem]:
+    """Parse message content, normalizing to a list of ContentItems.
+
+    Always returns a list for consistent downstream handling. String content
+    is wrapped in a TextContent item.
 
     Args:
         content_data: Raw content data (string or list of items)
@@ -853,12 +853,19 @@ def parse_message_content(
             parse_assistant_content_item for type-specific parsing.
     """
     if isinstance(content_data, str):
-        return content_data
+        return [TextContent(type="text", text=content_data)]
     elif isinstance(content_data, list):
-        content_list = cast(List[Dict[str, Any]], content_data)
-        return [item_parser(item) for item in content_list]
+        content_list = cast(list[Any], content_data)
+        result: list[ContentItem] = []
+        for item in content_list:
+            if isinstance(item, dict):
+                result.append(item_parser(cast(dict[str, Any], item)))
+            else:
+                # Non-dict items (e.g., raw strings) become TextContent
+                result.append(TextContent(type="text", text=str(item)))
+        return result
     else:
-        return str(content_data)
+        return [TextContent(type="text", text=str(content_data))]
 
 
 # =============================================================================
@@ -866,7 +873,7 @@ def parse_message_content(
 # =============================================================================
 
 
-def parse_transcript_entry(data: Dict[str, Any]) -> TranscriptEntry:
+def parse_transcript_entry(data: dict[str, Any]) -> TranscriptEntry:
     """
     Parse a JSON dictionary into the appropriate TranscriptEntry type.
 
@@ -897,14 +904,14 @@ def parse_transcript_entry(data: Dict[str, Any]) -> TranscriptEntry:
             data_copy["toolUseResult"], list
         ):
             # Check if it's a list of content items (MCP tool results)
-            tool_use_result = cast(List[Any], data_copy["toolUseResult"])
+            tool_use_result = cast(list[Any], data_copy["toolUseResult"])
             if (
                 tool_use_result
                 and isinstance(tool_use_result[0], dict)
                 and "type" in tool_use_result[0]
             ):
                 data_copy["toolUseResult"] = [
-                    parse_content_item(cast(Dict[str, Any], item))
+                    parse_content_item(cast(dict[str, Any], item))
                     for item in tool_use_result
                     if isinstance(item, dict)
                 ]
diff --git a/claude_code_log/renderer.py b/claude_code_log/renderer.py
index 5b375380..680d558e 100644
--- a/claude_code_log/renderer.py
+++ b/claude_code_log/renderer.py
@@ -4,7 +4,7 @@
 import time
 from dataclasses import dataclass, replace
 from pathlib import Path
-from typing import Any, Dict, List, Optional, Tuple, TYPE_CHECKING
+from typing import Any, Optional, Tuple, TYPE_CHECKING
 
 if TYPE_CHECKING:
     from .cache import CacheManager
@@ -181,7 +181,7 @@ def __init__(
         has_markdown: bool = False,
         message_title: Optional[str] = None,
         message_id: Optional[str] = None,
-        ancestry: Optional[List[str]] = None,
+        ancestry: Optional[list[str]] = None,
         has_children: bool = False,
         uuid: Optional[str] = None,
         parent_uuid: Optional[str] = None,
@@ -228,7 +228,7 @@ def __init__(
         self.pair_role: Optional[str] = None  # "pair_first", "pair_last", "pair_middle"
         self.pair_duration: Optional[str] = None  # Duration for pair_last messages
         # Children for tree-based rendering (future use)
-        self.children: List["TemplateMessage"] = []
+        self.children: list["TemplateMessage"] = []
 
     def get_immediate_children_label(self) -> str:
         """Generate human-readable label for immediate children."""
@@ -238,26 +238,26 @@ def get_total_descendants_label(self) -> str:
         """Generate human-readable label for all descendants."""
         return _format_type_counts(self.total_descendants_by_type)
 
-    def flatten(self) -> List["TemplateMessage"]:
+    def flatten(self) -> list["TemplateMessage"]:
         """Recursively flatten this message and all children into a list.
 
         Returns a list with this message followed by all descendants in
         depth-first order. This provides backward compatibility with the
         flat-list template rendering approach.
         """
-        result: List["TemplateMessage"] = [self]
+        result: list["TemplateMessage"] = [self]
         for child in self.children:
             result.extend(child.flatten())
         return result
 
     @staticmethod
-    def flatten_all(messages: List["TemplateMessage"]) -> List["TemplateMessage"]:
+    def flatten_all(messages: list["TemplateMessage"]) -> list["TemplateMessage"]:
         """Flatten a list of root messages into a single flat list.
 
         Useful for converting a tree structure back to a flat list for
         templates that expect the traditional flat message list.
         """
-        result: List["TemplateMessage"] = []
+        result: list["TemplateMessage"] = []
         for message in messages:
             result.extend(message.flatten())
         return result
@@ -266,7 +266,7 @@ def flatten_all(messages: List["TemplateMessage"]) -> List["TemplateMessage"]:
 class TemplateProject:
     """Structured project data for template rendering."""
 
-    def __init__(self, project_data: Dict[str, Any]):
+    def __init__(self, project_data: dict[str, Any]):
         self.name = project_data["name"]
         self.html_file = project_data["html_file"]
         self.jsonl_count = project_data["jsonl_count"]
@@ -318,7 +318,7 @@ def __init__(self, project_data: Dict[str, Any]):
         # Format token usage
         self.token_summary = ""
         if self.total_input_tokens > 0 or self.total_output_tokens > 0:
-            token_parts: List[str] = []
+            token_parts: list[str] = []
             if self.total_input_tokens > 0:
                 token_parts.append(f"Input: {self.total_input_tokens}")
             if self.total_output_tokens > 0:
@@ -335,7 +335,7 @@ def __init__(self, project_data: Dict[str, Any]):
 class TemplateSummary:
     """Summary statistics for template rendering."""
 
-    def __init__(self, project_summaries: List[Dict[str, Any]]):
+    def __init__(self, project_summaries: list[dict[str, Any]]):
         self.total_projects = len(project_summaries)
         self.total_jsonl = sum(p["jsonl_count"] for p in project_summaries)
         self.total_messages = sum(p["message_count"] for p in project_summaries)
@@ -400,7 +400,7 @@ def __init__(self, project_summaries: List[Dict[str, Any]]):
         # Format token usage summary
         self.token_summary = ""
         if self.total_input_tokens > 0 or self.total_output_tokens > 0:
-            token_parts: List[str] = []
+            token_parts: list[str] = []
             if self.total_input_tokens > 0:
                 token_parts.append(f"Input: {self.total_input_tokens}")
             if self.total_output_tokens > 0:
@@ -418,8 +418,8 @@ def __init__(self, project_summaries: List[Dict[str, Any]]):
 
 
 def generate_template_messages(
-    messages: List[TranscriptEntry],
-) -> Tuple[List[TemplateMessage], List[Dict[str, Any]]]:
+    messages: list[TranscriptEntry],
+) -> Tuple[list[TemplateMessage], list[dict[str, Any]]]:
     """Generate template messages and session navigation from transcript messages.
 
     This is the format-neutral rendering step that produces data structures
@@ -515,14 +515,14 @@ def generate_template_messages(
 # -- Session Utilities --------------------------------------------------------
 
 
-def prepare_session_summaries(messages: List[TranscriptEntry]) -> None:
+def prepare_session_summaries(messages: list[TranscriptEntry]) -> None:
     """Pre-process messages to find and attach session summaries.
 
     Modifies messages in place by attaching _session_summary attribute.
     """
-    session_summaries: Dict[str, str] = {}
-    uuid_to_session: Dict[str, str] = {}
-    uuid_to_session_backup: Dict[str, str] = {}
+    session_summaries: dict[str, str] = {}
+    uuid_to_session: dict[str, str] = {}
+    uuid_to_session_backup: dict[str, str] = {}
 
     # Build mapping from message UUID to session ID
     for message in messages:
@@ -558,9 +558,9 @@ def prepare_session_summaries(messages: List[TranscriptEntry]) -> None:
 
 
 def prepare_session_navigation(
-    sessions: Dict[str, Dict[str, Any]],
-    session_order: List[str],
-) -> List[Dict[str, Any]]:
+    sessions: dict[str, dict[str, Any]],
+    session_order: list[str],
+) -> list[dict[str, Any]]:
     """Prepare session navigation data for template rendering.
 
     Args:
@@ -570,7 +570,7 @@ def prepare_session_navigation(
     Returns:
         List of session navigation dicts for template rendering
     """
-    session_nav: List[Dict[str, Any]] = []
+    session_nav: list[dict[str, Any]] = []
 
     for session_id in session_order:
         session_info = sessions[session_id]
@@ -592,7 +592,7 @@ def prepare_session_navigation(
         total_cache_read = session_info["total_cache_read_tokens"]
 
         if total_input > 0 or total_output > 0:
-            token_parts: List[str] = []
+            token_parts: list[str] = []
             if total_input > 0:
                 token_parts.append(f"Input: {total_input}")
             if total_output > 0:
@@ -668,7 +668,7 @@ def _process_local_command_output(
     # If parsing fails, content will be None and caller will handle fallback
 
     message_type = "user"
-    message_title = "Command Output"
+    message_title = "Command output"
     return modifiers, content, message_type, message_title
 
 
@@ -683,7 +683,7 @@ def _process_bash_input(
     # If parsing fails, content will be None and caller will handle fallback
 
     message_type = "bash-input"
-    message_title = "Bash"
+    message_title = "Bash command"
     return modifiers, content, message_type, message_title
 
 
@@ -697,13 +697,13 @@ def _process_bash_output(
     content = parse_bash_output(text_content)
     # If parsing fails, content will be None - caller/renderer handles empty output
 
-    message_type = "bash"
-    message_title = "Bash"
+    message_type = "bash-output"
+    message_title = "Command output"
     return modifiers, content, message_type, message_title
 
 
 def _process_regular_message(
-    text_only_content: List[ContentItem],
+    text_only_content: list[ContentItem],
     message_type: str,
     is_sidechain: bool,
     is_meta: bool = False,
@@ -761,7 +761,7 @@ def _process_regular_message(
     if is_sidechain:
         # Update message title for display (only non-user types reach here)
         if not is_compacted:
-            message_title = "🔗 Sub-assistant"
+            message_title = "Sub-assistant"
 
     modifiers = MessageModifiers(
         is_sidechain=is_sidechain,
@@ -849,7 +849,7 @@ class ToolItemResult:
 
 def _process_tool_use_item(
     tool_item: ContentItem,
-    tool_use_context: Dict[str, ToolUseContent],
+    tool_use_context: dict[str, ToolUseContent],
 ) -> Optional[ToolItemResult]:
     """Process a tool_use content item.
 
@@ -891,7 +891,7 @@ def _process_tool_use_item(
 
 def _process_tool_result_item(
     tool_item: ContentItem,
-    tool_use_context: Dict[str, ToolUseContent],
+    tool_use_context: dict[str, ToolUseContent],
 ) -> Optional[ToolItemResult]:
     """Process a tool_result content item.
 
@@ -938,7 +938,7 @@ def _process_tool_result_item(
     pending_dedup: Optional[str] = None
     if result_tool_name == "Task":
         # Extract text content from tool result
-        # Note: tool_result.content can be str or List[Dict[str, Any]]
+        # Note: tool_result.content can be str or list[dict[str, Any]]
         if isinstance(tool_result.content, str):
             task_result_content = tool_result.content.strip()
         else:
@@ -1019,24 +1019,24 @@ class PairingIndices:
     """
 
     # (session_id, tool_use_id) -> message index for tool_use messages
-    tool_use: Dict[tuple[str, str], int]
+    tool_use: dict[tuple[str, str], int]
     # (session_id, tool_use_id) -> message index for tool_result messages
-    tool_result: Dict[tuple[str, str], int]
+    tool_result: dict[tuple[str, str], int]
     # uuid -> message index for system messages (parent-child pairing)
-    uuid: Dict[str, int]
+    uuid: dict[str, int]
     # parent_uuid -> message index for slash-command messages
-    slash_command_by_parent: Dict[str, int]
+    slash_command_by_parent: dict[str, int]
 
 
-def _build_pairing_indices(messages: List[TemplateMessage]) -> PairingIndices:
+def _build_pairing_indices(messages: list[TemplateMessage]) -> PairingIndices:
     """Build indices for efficient message pairing lookups.
 
     Single pass through messages to build all indices needed for pairing.
     """
-    tool_use_index: Dict[tuple[str, str], int] = {}
-    tool_result_index: Dict[tuple[str, str], int] = {}
-    uuid_index: Dict[str, int] = {}
-    slash_command_by_parent: Dict[str, int] = {}
+    tool_use_index: dict[tuple[str, str], int] = {}
+    tool_result_index: dict[tuple[str, str], int] = {}
+    uuid_index: dict[str, int] = {}
+    slash_command_by_parent: dict[str, int] = {}
 
     for i, msg in enumerate(messages):
         # Index tool_use and tool_result by (session_id, tool_use_id)
@@ -1104,7 +1104,7 @@ def _try_pair_adjacent(
 
 def _try_pair_by_index(
     current: TemplateMessage,
-    messages: List[TemplateMessage],
+    messages: list[TemplateMessage],
     indices: PairingIndices,
 ) -> None:
     """Try to pair current message with another using index lookups.
@@ -1134,7 +1134,7 @@ def _try_pair_by_index(
             _mark_pair(current, slash_msg)
 
 
-def _identify_message_pairs(messages: List[TemplateMessage]) -> None:
+def _identify_message_pairs(messages: list[TemplateMessage]) -> None:
     """Identify and mark paired messages (e.g., command + output, tool use + result).
 
     Modifies messages in-place by setting is_paired and pair_role fields.
@@ -1173,7 +1173,7 @@ def _identify_message_pairs(messages: List[TemplateMessage]) -> None:
         i += 1
 
 
-def _reorder_paired_messages(messages: List[TemplateMessage]) -> List[TemplateMessage]:
+def _reorder_paired_messages(messages: list[TemplateMessage]) -> list[TemplateMessage]:
     """Reorder messages so paired messages are adjacent while preserving chronological order.
 
     - Unpaired messages and first messages in pairs maintain chronological order
@@ -1189,11 +1189,11 @@ def _reorder_paired_messages(messages: List[TemplateMessage]) -> List[TemplateMe
 
     # Build index of pair_last messages by (session_id, tool_use_id)
     # Session ID is included to prevent cross-session pairing when sessions are resumed
-    pair_last_index: Dict[
+    pair_last_index: dict[
         tuple[str, str], int
     ] = {}  # (session_id, tool_use_id) -> message index
     # Index slash-command pair_last messages by parent_uuid
-    slash_command_pair_index: Dict[str, int] = {}  # parent_uuid -> message index
+    slash_command_pair_index: dict[str, int] = {}  # parent_uuid -> message index
 
     for i, msg in enumerate(messages):
         if (
@@ -1214,7 +1214,7 @@ def _reorder_paired_messages(messages: List[TemplateMessage]) -> List[TemplateMe
             slash_command_pair_index[msg.parent_uuid] = i
 
     # Create reordered list
-    reordered: List[TemplateMessage] = []
+    reordered: list[TemplateMessage] = []
     skip_indices: set[int] = set()
 
     for i, msg in enumerate(messages):
@@ -1343,7 +1343,7 @@ def _get_message_hierarchy_level(msg: TemplateMessage) -> int:
     return 1
 
 
-def _build_message_hierarchy(messages: List[TemplateMessage]) -> None:
+def _build_message_hierarchy(messages: list[TemplateMessage]) -> None:
     """Build message_id and ancestry for all messages based on their current order.
 
     This should be called after all reordering operations (pair reordering, sidechain
@@ -1355,7 +1355,7 @@ def _build_message_hierarchy(messages: List[TemplateMessage]) -> None:
     Args:
         messages: List of template messages in their final order (modified in place)
     """
-    hierarchy_stack: List[tuple[int, str]] = []
+    hierarchy_stack: list[tuple[int, str]] = []
     message_id_counter = 0
 
     for message in messages:
@@ -1389,7 +1389,7 @@ def _build_message_hierarchy(messages: List[TemplateMessage]) -> None:
         message.ancestry = ancestry
 
 
-def _mark_messages_with_children(messages: List[TemplateMessage]) -> None:
+def _mark_messages_with_children(messages: list[TemplateMessage]) -> None:
     """Mark messages that have children and calculate descendant counts.
 
     Efficiently calculates:
@@ -1445,7 +1445,7 @@ def _mark_messages_with_children(messages: List[TemplateMessage]) -> None:
                 )
 
 
-def _build_message_tree(messages: List[TemplateMessage]) -> List[TemplateMessage]:
+def _build_message_tree(messages: list[TemplateMessage]) -> list[TemplateMessage]:
     """Build tree structure by populating children fields based on ancestry.
 
     This function takes a flat list of messages (with message_id and ancestry
@@ -1475,7 +1475,7 @@ def _build_message_tree(messages: List[TemplateMessage]) -> List[TemplateMessage
         message.children = []
 
     # Collect root messages (those with no ancestry)
-    root_messages: List[TemplateMessage] = []
+    root_messages: list[TemplateMessage] = []
 
     # Populate children based on ancestry
     for message in messages:
@@ -1496,8 +1496,8 @@ def _build_message_tree(messages: List[TemplateMessage]) -> List[TemplateMessage
 
 
 def _reorder_session_template_messages(
-    messages: List[TemplateMessage],
-) -> List[TemplateMessage]:
+    messages: list[TemplateMessage],
+) -> list[TemplateMessage]:
     """Reorder template messages to group all messages under their correct session headers.
 
     When a user resumes session A into session B, Claude Code copies messages from
@@ -1516,8 +1516,8 @@ def _reorder_session_template_messages(
         Reordered messages with all messages grouped under their session headers
     """
     # First pass: extract session headers and group non-header messages by session_id
-    session_headers: List[TemplateMessage] = []
-    session_messages_map: Dict[str, List[TemplateMessage]] = {}
+    session_headers: list[TemplateMessage] = []
+    session_messages_map: dict[str, list[TemplateMessage]] = {}
 
     for message in messages:
         if message.is_session_header:
@@ -1537,7 +1537,7 @@ def _reorder_session_template_messages(
         return messages
 
     # Second pass: for each session header, insert all messages with that session_id
-    result: List[TemplateMessage] = []
+    result: list[TemplateMessage] = []
     used_sessions: set[str] = set()
 
     for header in session_headers:
@@ -1558,8 +1558,8 @@ def _reorder_session_template_messages(
 
 
 def _reorder_sidechain_template_messages(
-    messages: List[TemplateMessage],
-) -> List[TemplateMessage]:
+    messages: list[TemplateMessage],
+) -> list[TemplateMessage]:
     """Reorder template messages to place sidechains immediately after their Task results.
 
     When parallel Task agents run, their sidechain messages may appear in arbitrary
@@ -1581,8 +1581,8 @@ def _reorder_sidechain_template_messages(
         Reordered messages with sidechains properly placed after their Task results
     """
     # First pass: extract sidechains grouped by agent_id
-    main_messages: List[TemplateMessage] = []
-    sidechain_map: Dict[str, List[TemplateMessage]] = {}
+    main_messages: list[TemplateMessage] = []
+    sidechain_map: dict[str, list[TemplateMessage]] = {}
 
     for message in messages:
         is_sidechain = message.modifiers.is_sidechain
@@ -1602,7 +1602,7 @@ def _reorder_sidechain_template_messages(
 
     # Second pass: insert sidechains after their Task result messages
     # Also perform deduplication of sidechain assistants vs Task results
-    result: List[TemplateMessage] = []
+    result: list[TemplateMessage] = []
     used_agents: set[str] = set()
 
     for message in main_messages:
@@ -1662,7 +1662,7 @@ def _reorder_sidechain_template_messages(
     return result
 
 
-def _filter_messages(messages: List[TranscriptEntry]) -> List[TranscriptEntry]:
+def _filter_messages(messages: list[TranscriptEntry]) -> list[TranscriptEntry]:
     """Filter messages to those that should be rendered.
 
     This function filters out:
@@ -1680,7 +1680,7 @@ def _filter_messages(messages: List[TranscriptEntry]) -> List[TranscriptEntry]:
     Returns:
         Filtered list of messages that should be rendered
     """
-    filtered: List[TranscriptEntry] = []
+    filtered: list[TranscriptEntry] = []
 
     for message in messages:
         message_type = message.type
@@ -1700,28 +1700,25 @@ def _filter_messages(messages: List[TranscriptEntry]) -> List[TranscriptEntry]:
             continue
 
         # Get message content for filtering checks
+        message_content: list[ContentItem]
         if isinstance(message, QueueOperationTranscriptEntry):
-            message_content = message.content if message.content else []
+            content = message.content
+            message_content = content if isinstance(content, list) else []
         else:
-            message_content = message.message.content  # type: ignore
+            message_content = message.message.content  # type: ignore[union-attr]
 
         text_content = extract_text_content(message_content)
 
         # Skip if no meaningful content
         if not text_content.strip():
             # Check for tool items
-            if isinstance(message_content, list):
-                has_tool_items = any(
-                    isinstance(
-                        item, (ToolUseContent, ToolResultContent, ThinkingContent)
-                    )
-                    or getattr(item, "type", None)
-                    in ("tool_use", "tool_result", "thinking")
-                    for item in message_content
-                )
-                if not has_tool_items:
-                    continue
-            else:
+            has_tool_items = any(
+                isinstance(item, (ToolUseContent, ToolResultContent, ThinkingContent))
+                or getattr(item, "type", None)
+                in ("tool_use", "tool_result", "thinking")
+                for item in message_content
+            )
+            if not has_tool_items:
                 continue
 
         # Skip messages that should be filtered out
@@ -1730,14 +1727,13 @@ def _filter_messages(messages: List[TranscriptEntry]) -> List[TranscriptEntry]:
 
         # Skip sidechain user messages that are just prompts (no tool results)
         if message_type == MessageType.USER and getattr(message, "isSidechain", False):
-            if isinstance(message_content, list):
-                has_tool_results = any(
-                    getattr(item, "type", None) == "tool_result"
-                    or isinstance(item, ToolResultContent)
-                    for item in message_content
-                )
-                if not has_tool_results:
-                    continue
+            has_tool_results = any(
+                getattr(item, "type", None) == "tool_result"
+                or isinstance(item, ToolResultContent)
+                for item in message_content
+            )
+            if not has_tool_results:
+                continue
 
         # Message passes all filters
         filtered.append(message)
@@ -1746,10 +1742,10 @@ def _filter_messages(messages: List[TranscriptEntry]) -> List[TranscriptEntry]:
 
 
 def _collect_session_info(
-    messages: List[TranscriptEntry],
+    messages: list[TranscriptEntry],
 ) -> tuple[
-    Dict[str, Dict[str, Any]],  # sessions
-    List[str],  # session_order
+    dict[str, dict[str, Any]],  # sessions
+    list[str],  # session_order
     set[str],  # show_tokens_for_message
 ]:
     """Collect session metadata and token tracking from pre-filtered messages.
@@ -1771,8 +1767,8 @@ def _collect_session_info(
         - session_order: List of session IDs in chronological order
         - show_tokens_for_message: Set of message UUIDs that should display tokens
     """
-    sessions: Dict[str, Dict[str, Any]] = {}
-    session_order: List[str] = []
+    sessions: dict[str, dict[str, Any]] = {}
+    session_order: list[str] = []
 
     # Track requestIds to avoid double-counting token usage
     seen_request_ids: set[str] = set()
@@ -1867,10 +1863,10 @@ def _collect_session_info(
 
 
 def _render_messages(
-    messages: List[TranscriptEntry],
-    sessions: Dict[str, Dict[str, Any]],
+    messages: list[TranscriptEntry],
+    sessions: dict[str, dict[str, Any]],
     show_tokens_for_message: set[str],
-) -> List[TemplateMessage]:
+) -> list[TemplateMessage]:
     """Pass 2: Render pre-filtered messages to TemplateMessage objects.
 
     This pass creates the actual TemplateMessage objects for rendering:
@@ -1894,19 +1890,19 @@ def _render_messages(
     seen_sessions: set[str] = set()
 
     # Build mapping of tool_use_id to ToolUseContent for specialized tool result rendering
-    tool_use_context: Dict[str, ToolUseContent] = {}
+    tool_use_context: dict[str, ToolUseContent] = {}
 
     # Process messages into template-friendly format
-    template_messages: List[TemplateMessage] = []
+    template_messages: list[TemplateMessage] = []
 
     # Per-message timing tracking
-    message_timings: List[
+    message_timings: list[
         tuple[float, str, int, str]
     ] = []  # (duration, message_type, index, uuid)
 
     # Track expensive operations
-    markdown_timings: List[tuple[float, str]] = []  # (duration, context_uuid)
-    pygments_timings: List[tuple[float, str]] = []  # (duration, context_uuid)
+    markdown_timings: list[tuple[float, str]] = []  # (duration, context_uuid)
+    pygments_timings: list[tuple[float, str]] = []  # (duration, context_uuid)
 
     # Initialize timing tracking
     set_timing_var("_markdown_timings", markdown_timings)
@@ -1938,11 +1934,11 @@ def _render_messages(
         text_content = extract_text_content(message_content)  # type: ignore[arg-type]
 
         # Separate tool/thinking/image content from text content
-        tool_items: List[ContentItem] = []
-        text_only_content: List[ContentItem] = []
+        tool_items: list[ContentItem] = []
+        text_only_content: list[ContentItem] = []
 
         if isinstance(message_content, list):
-            text_only_items: List[ContentItem] = []
+            text_only_items: list[ContentItem] = []
             for item in message_content:  # type: ignore[union-attr]
                 item_type = getattr(item, "type", None)  # type: ignore[arg-type]
                 is_image = isinstance(item, ImageContent) or item_type == "image"
@@ -2199,8 +2195,8 @@ def _render_messages(
 
 
 def prepare_projects_index(
-    project_summaries: List[Dict[str, Any]],
-) -> tuple[List["TemplateProject"], "TemplateSummary"]:
+    project_summaries: list[dict[str, Any]],
+) -> tuple[list["TemplateProject"], "TemplateSummary"]:
     """Prepare project data for rendering in any format.
 
     Args:
@@ -2222,7 +2218,7 @@ def prepare_projects_index(
 
 
 def title_for_projects_index(
-    project_summaries: List[Dict[str, Any]],
+    project_summaries: list[dict[str, Any]],
     from_date: Optional[str] = None,
     to_date: Optional[str] = None,
 ) -> str:
@@ -2286,7 +2282,7 @@ def title_for_projects_index(
 
     # Add date range suffix if provided
     if from_date or to_date:
-        date_range_parts: List[str] = []
+        date_range_parts: list[str] = []
         if from_date:
             date_range_parts.append(f"from {from_date}")
         if to_date:
@@ -2308,7 +2304,7 @@ class Renderer:
 
     def generate(
         self,
-        messages: List[TranscriptEntry],
+        messages: list[TranscriptEntry],
         title: Optional[str] = None,
         combined_transcript_link: Optional[str] = None,
     ) -> Optional[str]:
@@ -2320,7 +2316,7 @@ def generate(
 
     def generate_session(
         self,
-        messages: List[TranscriptEntry],
+        messages: list[TranscriptEntry],
         session_id: str,
         title: Optional[str] = None,
         cache_manager: Optional["CacheManager"] = None,
@@ -2333,7 +2329,7 @@ def generate_session(
 
     def generate_projects_index(
         self,
-        project_summaries: List[Dict[str, Any]],
+        project_summaries: list[dict[str, Any]],
         from_date: Optional[str] = None,
         to_date: Optional[str] = None,
     ) -> Optional[str]:
diff --git a/claude_code_log/renderer_timings.py b/claude_code_log/renderer_timings.py
index fb5111cb..96aff4b7 100644
--- a/claude_code_log/renderer_timings.py
+++ b/claude_code_log/renderer_timings.py
@@ -7,7 +7,7 @@
 import os
 import time
 from contextlib import contextmanager
-from typing import List, Tuple, Iterator, Any, Dict, Callable, Union, Optional
+from typing import Tuple, Iterator, Any, Callable, Union, Optional
 
 # Performance debugging - enabled via CLAUDE_CODE_LOG_DEBUG_TIMING environment variable
 # Set to "1", "true", or "yes" to enable timing output
@@ -18,7 +18,7 @@
 )
 
 # Global timing data storage
-_timing_data: Dict[str, Any] = {}
+_timing_data: dict[str, Any] = {}
 
 
 def set_timing_var(name: str, value: Any) -> None:
@@ -111,8 +111,8 @@ def timing_stat(list_name: str) -> Iterator[None]:
 
 
 def report_timing_statistics(
-    message_timings: List[Tuple[float, str, int, str]],
-    operation_timings: List[Tuple[str, List[Tuple[float, str]]]],
+    message_timings: list[Tuple[float, str, int, str]],
+    operation_timings: list[Tuple[str, list[Tuple[float, str]]]],
 ) -> None:
     """Report timing statistics for message rendering.
 
diff --git a/claude_code_log/tui.py b/claude_code_log/tui.py
index 861a9db0..f3a69b5b 100644
--- a/claude_code_log/tui.py
+++ b/claude_code_log/tui.py
@@ -5,7 +5,7 @@
 import webbrowser
 from datetime import datetime
 from pathlib import Path
-from typing import ClassVar, Dict, Optional, cast
+from typing import ClassVar, Optional, cast
 
 from textual.app import App, ComposeResult
 from textual.binding import Binding, BindingType
@@ -230,7 +230,7 @@ class SessionBrowser(App[Optional[str]]):
     is_expanded: reactive[bool] = reactive(False)
     project_path: Path
     cache_manager: CacheManager
-    sessions: Dict[str, SessionCacheData]
+    sessions: dict[str, SessionCacheData]
 
     def __init__(self, project_path: Path):
         """Initialize the session browser with a project path."""
diff --git a/claude_code_log/utils.py b/claude_code_log/utils.py
index 82f3a733..e0ad25fd 100644
--- a/claude_code_log/utils.py
+++ b/claude_code_log/utils.py
@@ -2,9 +2,9 @@
 """Utility functions for message filtering and processing."""
 
 import re
-from datetime import datetime
+from datetime import datetime, timezone
 from pathlib import Path
-from typing import Dict, List, Optional, Union
+from typing import Optional
 
 from claude_code_log.cache import SessionCacheData
 from .models import ContentItem, TextContent, TranscriptEntry, UserTranscriptEntry
@@ -26,15 +26,7 @@ def format_timestamp(timestamp_str: str | None) -> str:
         dt = datetime.fromisoformat(timestamp_str.replace("Z", "+00:00"))
         # Convert to UTC if timezone-aware
         if dt.tzinfo is not None:
-            utc_timetuple = dt.utctimetuple()
-            dt = datetime(
-                utc_timetuple.tm_year,
-                utc_timetuple.tm_mon,
-                utc_timetuple.tm_mday,
-                utc_timetuple.tm_hour,
-                utc_timetuple.tm_min,
-                utc_timetuple.tm_sec,
-            )
+            dt = dt.astimezone(timezone.utc).replace(tzinfo=None)
         return dt.strftime("%Y-%m-%d %H:%M:%S")
     except (ValueError, AttributeError):
         return timestamp_str
@@ -63,7 +55,7 @@ def format_timestamp_range(first_timestamp: str, last_timestamp: str) -> str:
 
 
 def get_project_display_name(
-    project_dir_name: str, working_directories: Optional[List[str]] = None
+    project_dir_name: str, working_directories: Optional[list[str]] = None
 ) -> str:
     """Get the display name for a project based on working directories.
 
@@ -164,24 +156,19 @@ def create_session_preview(text_content: str) -> str:
     return preview_content
 
 
-def extract_text_content_length(content: Union[str, List[ContentItem]]) -> int:
+def extract_text_content_length(content: list[ContentItem]) -> int:
     """Get the length of text content for quick checks without full extraction."""
-    if isinstance(content, str):
-        return len(content.strip())
-
-    # For list content, count only text items
     total_length = 0
     for item in content:
         # Only count TextContent items, skip tool/thinking/image items
         if isinstance(item, TextContent):
             total_length += len(item.text.strip())
-
     return total_length
 
 
 def extract_working_directories(
-    entries: List[TranscriptEntry] | List[SessionCacheData],
-) -> List[str]:
+    entries: list[TranscriptEntry] | list[SessionCacheData],
+) -> list[str]:
     """Extract unique working directories from a list of entries.
 
     Ordered by timestamp (most recent first).
@@ -314,7 +301,7 @@ def _extract_file_path(content: str) -> str | None:
     return text_content
 
 
-def get_warmup_session_ids(messages: List[TranscriptEntry]) -> set[str]:
+def get_warmup_session_ids(messages: list[TranscriptEntry]) -> set[str]:
     """Get set of session IDs that are warmup-only sessions.
 
     Pre-computes warmup status for all sessions for efficiency (O(n) once,
@@ -329,7 +316,7 @@ def get_warmup_session_ids(messages: List[TranscriptEntry]) -> set[str]:
     from .parser import extract_text_content
 
     # Group user message text by session
-    session_user_messages: Dict[str, List[str]] = {}
+    session_user_messages: dict[str, list[str]] = {}
 
     for message in messages:
         if isinstance(message, UserTranscriptEntry) and hasattr(message, "message"):
diff --git a/dev-docs/FOLD_STATE_DIAGRAM.md b/dev-docs/FOLD_STATE_DIAGRAM.md
index a8af2c2d..9ac5b106 100644
--- a/dev-docs/FOLD_STATE_DIAGRAM.md
+++ b/dev-docs/FOLD_STATE_DIAGRAM.md
@@ -273,6 +273,6 @@ Paired messages (tool_use + tool_result, thinking + assistant) are handled as un
 
 ## References
 
-- [renderer.py](../claude_code_log/renderer.py) - Hierarchy functions (lines 2698-2850)
-- [templates/components/fold_bar.html](../claude_code_log/templates/components/fold_bar.html) - JavaScript controls
-- [css-classes.md](css-classes.md) - CSS class documentation
+- [renderer.py](../claude_code_log/renderer.py) - Message hierarchy functions (lines 1285-1493)
+- [transcript.html](../claude_code_log/html/templates/transcript.html) - Fold/unfold JavaScript controls
+- [message_styles.css](../claude_code_log/html/templates/components/message_styles.css) - Fold state CSS styles
diff --git a/dev-docs/MESSAGE_REFACTORING.md b/dev-docs/MESSAGE_REFACTORING.md
index 230f5856..90881e40 100755
--- a/dev-docs/MESSAGE_REFACTORING.md
+++ b/dev-docs/MESSAGE_REFACTORING.md
@@ -51,7 +51,7 @@ This branch implements tree-based message rendering. See [TEMPLATE_MESSAGE_CHILD
   - Template unchanged - still receives flat list (Phase 3 future work)
 
 **Architecture:**
-```
+```text
 TranscriptEntry[] → generate_template_messages() → root_messages (tree)
                                                           ↓
                     HtmlRenderer._flatten_preorder() → flat_list
@@ -138,7 +138,7 @@ Adds text/markdown/chat output formats via new `content_extractor.py` module.
 **Goal**: Extract ANSI color conversion to dedicated module
 
 **Changes**:
-- ✅ Created `claude_code_log/ansi_colors.py` (261 lines)
+- ✅ Created `claude_code_log/html/ansi_colors.py` (261 lines)
 - ✅ Moved `_convert_ansi_to_html()` → `convert_ansi_to_html()`
 - ✅ Updated imports in `renderer.py`
 - ✅ Updated test imports in `test_ansi_colors.py`
@@ -150,7 +150,7 @@ Adds text/markdown/chat output formats via new `content_extractor.py` module.
 **Goal**: Extract code-related rendering (Pygments highlighting, diff rendering) to dedicated module
 
 **Changes**:
-- ✅ Created `claude_code_log/renderer_code.py` (330 lines)
+- ✅ Created `claude_code_log/html/renderer_code.py` (330 lines)
 - ✅ Moved `_highlight_code_with_pygments()` → `highlight_code_with_pygments()`
 - ✅ Moved `_truncate_highlighted_preview()` → `truncate_highlighted_preview()`
 - ✅ Moved `_render_single_diff()` → `render_single_diff()`
@@ -392,10 +392,7 @@ The original plan called for two-stage (parse + render) splits. This was achieve
 - **Tree-first architecture** means HtmlRenderer traverses tree and formats during pre-order walk
 
 **Step 9 Status**:
-`generate_projects_index_html()` remains in renderer.py because:
-- Mixes format-neutral data preparation (TemplateProject/TemplateSummary) with HTML generation
-- Moving just the HTML part would require restructuring the data flow
-- Low priority: function works correctly and is ~100 lines
+`generate_projects_index_html()` is now in `claude_code_log/html/renderer.py` (thin wrapper over `HtmlRenderer.generate_projects_index()`).
 
 **Dependencies**:
 - Requires Phase 9 (type safety) for clean interfaces ✅
diff --git a/dev-docs/messages.md b/dev-docs/messages.md
index ce455b47..ee76bc65 100644
--- a/dev-docs/messages.md
+++ b/dev-docs/messages.md
@@ -16,7 +16,7 @@ This document maps input types to their intermediate and output representations.
 
 ## Data Flow: From Transcript Entries to Rendered Messages
 
-```
+```text
 JSONL Parsing (parser.py)
 │
 ├── UserTranscriptEntry
@@ -168,6 +168,11 @@ Based on flags and tag patterns in `TextContent`, user text messages are classif
 }
 ```
 
+> **Note**: These are "caveat" messages that precede slash command messages (with
+> `<command-name>` tags). They instruct the LLM to not respond to the following
+> local command output unless explicitly asked. The actual slash command details
+> appear in the subsequent message with tags.
+
 ### Slash Command (Tags)
 
 - **Condition**: Contains `<command-name>` tags
@@ -183,6 +188,11 @@ class SlashCommandContent(MessageContent):
     command_contents: str  # Content inside command
 ```
 
+> **Note**: Both built-in commands (e.g., `/init`, `/model`, `/context`) and
+> user-defined commands (e.g., `/my-command` from `~/.claude/commands/my-command.md`)
+> use the same `<command-name>` tag format. There is no field in the JSONL to
+> differentiate between them.
+
 ### Command Output
 
 - **Condition**: Contains `<local-command-stdout>` tags
@@ -201,7 +211,7 @@ class CommandOutputContent(MessageContent):
 
 - **Condition**: Contains `<bash-input>` tags
 - **Content Model**: `BashInputContent`
-- **CSS Class**: Part of bash tool pairing
+- **CSS Class**: `bash-input` (filtered by User)
 - **Files**: [bash_input.json](messages/user/bash_input.json)
 
 ```python
@@ -216,7 +226,7 @@ The corresponding output uses `<bash-stdout>` and optionally `<bash-stderr>` tag
 
 - **Condition**: Contains `<bash-stdout>` tags
 - **Content Model**: `BashOutputContent`
-- **CSS Class**: Part of bash tool pairing
+- **CSS Class**: `bash-output` (filtered by User)
 - **Files**: [bash_output.json](messages/user/bash_output.json)
 
 ### Compacted Conversation
@@ -701,7 +711,7 @@ The message hierarchy is determined by **sequence and message type**, not by `pa
 - Tool use/result pairs nest under assistant responses (Level 3)
 - Sidechain messages nest under their Task result (Level 4+)
 
-```
+```text
 Session header (Level 0)
 └── User message (Level 1)
     ├── System message (Level 2)
diff --git a/test/__snapshots__/test_snapshot_html.ambr b/test/__snapshots__/test_snapshot_html.ambr
index c7d4aab1..018f4fa1 100644
--- a/test/__snapshots__/test_snapshot_html.ambr
+++ b/test/__snapshots__/test_snapshot_html.ambr
@@ -4316,7 +4316,11 @@
               'thinking': { id: 'thinking', content: '💭 Thinking', style: 'background-color: #fce4ec;' },
               'system': { id: 'system', content: '⚙️ System', style: 'background-color: #ffeee1;' },
               'image': { id: 'image', content: '🖼️ Image', style: 'background-color: #e1f5fe;' },
-              'sidechain': { id: 'sidechain', content: '🔗 Sub-assistant', style: 'background-color: #f5f5f5;' }
+              'sidechain': { id: 'sidechain', content: '🔗 Sub-assistant', style: 'background-color: #f5f5f5;' },
+              'slash-command': { id: 'slash-command', content: '⌨️ Slash Command', style: 'background-color: #e8eaf6;' },
+              'command-output': { id: 'command-output', content: '📋 Command Output', style: 'background-color: #efebe9;' },
+              'bash-input': { id: 'bash-input', content: '💻 Bash Input', style: 'background-color: #e8eaf6;' },
+              'bash-output': { id: 'bash-output', content: '📄 Bash Output', style: 'background-color: #efebe9;' }
           };
   
           // Build timeline data from messages
@@ -4342,6 +4346,14 @@
                       messageType = 'sidechain';
                   } else if (classList.includes('system-warning') || classList.includes('system-error') || classList.includes('system-info')) {
                       messageType = 'system';
+                  } else if (classList.includes('slash-command')) {
+                      messageType = 'slash-command';
+                  } else if (classList.includes('command-output')) {
+                      messageType = 'command-output';
+                  } else if (classList.includes('bash-input')) {
+                      messageType = 'bash-input';
+                  } else if (classList.includes('bash-output')) {
+                      messageType = 'bash-output';
                   } else {
                       // Look for standard message types
                       messageType = classList.find(cls =>
@@ -4466,10 +4478,15 @@
               const activeTypes = Array.from(document.querySelectorAll('.filter-toggle.active'))
                   .map(toggle => toggle.dataset.type);
   
+              // Get all filter toggle types (to know which groups have filter controls)
+              const allFilterTypes = Array.from(document.querySelectorAll('.filter-toggle'))
+                  .map(toggle => toggle.dataset.type);
+  
               // Update groups visibility based on filter states
+              // Groups with filter toggles follow toggle state; groups without toggles stay visible
               const updatedGroups = groups.map(group => ({
                   ...group,
-                  visible: activeTypes.includes(group.id)
+                  visible: allFilterTypes.includes(group.id) ? activeTypes.includes(group.id) : true
               }));
   
               // Update timeline groups
@@ -4547,7 +4564,7 @@
                       axis: 2
                   },
                   groupOrder: (a, b) => {
-                      const order = ['user', 'assistant', 'sidechain', 'tool_use', 'tool_result', 'thinking', 'system', 'image'];
+                      const order = ['user', 'system', 'slash-command', 'command-output', 'bash-input', 'bash-output', 'thinking', 'assistant', 'sidechain', 'tool_use', 'tool_result', 'image'];
                       return order.indexOf(a.id) - order.indexOf(b.id);
                   }
               };
@@ -5359,7 +5376,7 @@
   
               // Count messages by type and update button labels
               function updateMessageCounts() {
-                  const messageTypes = ['user', 'assistant', 'sidechain', 'system', 'thinking', 'image'];
+                  const messageTypes = ['assistant', 'sidechain', 'system', 'thinking', 'image'];
   
                   messageTypes.forEach(type => {
                       const messages = document.querySelectorAll(`.message.${type}:not(.session-header)`);
@@ -5379,8 +5396,23 @@
                       }
                   });
   
-                  // Handle combined "tool" filter (tool_use + tool_result + bash messages)
-                  const toolMessages = document.querySelectorAll(`.message.tool_use:not(.session-header), .message.tool_result:not(.session-header), .message.bash-input:not(.session-header), .message.bash-output:not(.session-header)`);
+                  // Handle combined "user" filter (user + bash-input + bash-output)
+                  const userMessages = document.querySelectorAll(`.message.user:not(.session-header), .message.bash-input:not(.session-header), .message.bash-output:not(.session-header)`);
+                  const userCount = userMessages.length;
+                  const userToggle = document.querySelector(`[data-type="user"]`);
+                  const userCountSpan = userToggle ? userToggle.querySelector('.count') : null;
+  
+                  if (userCountSpan) {
+                      userCountSpan.textContent = `(${userCount})`;
+                      if (userCount === 0) {
+                          userToggle.style.display = 'none';
+                      } else {
+                          userToggle.style.display = 'flex';
+                      }
+                  }
+  
+                  // Handle combined "tool" filter (tool_use + tool_result)
+                  const toolMessages = document.querySelectorAll(`.message.tool_use:not(.session-header), .message.tool_result:not(.session-header)`);
                   const toolCount = toolMessages.length;
                   const toolToggle = document.querySelector(`[data-type="tool"]`);
                   const toolCountSpan = toolToggle ? toolToggle.querySelector('.count') : null;
@@ -5401,11 +5433,14 @@
                       .filter(toggle => toggle.classList.contains('active'))
                       .map(toggle => toggle.dataset.type);
   
-                  // Expand "tool" to include tool_use, tool_result, and bash messages
+                  // Expand filter types to their corresponding CSS classes
                   const expandedTypes = [];
                   activeTypes.forEach(type => {
                       if (type === 'tool') {
-                          expandedTypes.push('tool_use', 'tool_result', 'bash-input', 'bash-output');
+                          expandedTypes.push('tool_use', 'tool_result');
+                      } else if (type === 'user') {
+                          // User filter includes bash commands (user-initiated)
+                          expandedTypes.push('user', 'bash-input', 'bash-output');
                       } else {
                           expandedTypes.push(type);
                       }
@@ -5449,7 +5484,7 @@
               }
   
               function updateVisibleCounts() {
-                  const messageTypes = ['user', 'assistant', 'sidechain', 'system', 'thinking', 'image'];
+                  const messageTypes = ['assistant', 'sidechain', 'system', 'thinking', 'image'];
   
                   messageTypes.forEach(type => {
                       const visibleMessages = document.querySelectorAll(`.message.${type}:not(.session-header):not(.filtered-hidden)`);
@@ -5476,9 +5511,32 @@
                       }
                   });
   
-                  // Handle combined "tool" filter separately (includes bash messages)
-                  const visibleToolMessages = document.querySelectorAll(`.message.tool_use:not(.session-header):not(.filtered-hidden), .message.tool_result:not(.session-header):not(.filtered-hidden), .message.bash-input:not(.session-header):not(.filtered-hidden), .message.bash-output:not(.session-header):not(.filtered-hidden)`);
-                  const totalToolMessages = document.querySelectorAll(`.message.tool_use:not(.session-header), .message.tool_result:not(.session-header), .message.bash-input:not(.session-header), .message.bash-output:not(.session-header)`);
+                  // Handle combined "user" filter separately (includes bash messages)
+                  const visibleUserMessages = document.querySelectorAll(`.message.user:not(.session-header):not(.filtered-hidden), .message.bash-input:not(.session-header):not(.filtered-hidden), .message.bash-output:not(.session-header):not(.filtered-hidden)`);
+                  const totalUserMessages = document.querySelectorAll(`.message.user:not(.session-header), .message.bash-input:not(.session-header), .message.bash-output:not(.session-header)`);
+                  const visibleUserCount = visibleUserMessages.length;
+                  const totalUserCount = totalUserMessages.length;
+  
+                  const userToggle = document.querySelector(`[data-type="user"]`);
+                  const userCountSpan = userToggle ? userToggle.querySelector('.count') : null;
+  
+                  if (userCountSpan && totalUserCount > 0) {
+                      const activeTypes = Array.from(filterToggles)
+                          .filter(toggle => toggle.classList.contains('active'))
+                          .map(toggle => toggle.dataset.type);
+  
+                      const isFiltering = activeTypes.length < filterToggles.length;
+  
+                      if (isFiltering && visibleUserCount !== totalUserCount) {
+                          userCountSpan.textContent = `(${visibleUserCount}/${totalUserCount})`;
+                      } else {
+                          userCountSpan.textContent = `(${totalUserCount})`;
+                      }
+                  }
+  
+                  // Handle combined "tool" filter separately
+                  const visibleToolMessages = document.querySelectorAll(`.message.tool_use:not(.session-header):not(.filtered-hidden), .message.tool_result:not(.session-header):not(.filtered-hidden)`);
+                  const totalToolMessages = document.querySelectorAll(`.message.tool_use:not(.session-header), .message.tool_result:not(.session-header)`);
                   const visibleToolCount = visibleToolMessages.length;
                   const totalToolCount = totalToolMessages.length;
   
@@ -9052,7 +9110,11 @@
               'thinking': { id: 'thinking', content: '💭 Thinking', style: 'background-color: #fce4ec;' },
               'system': { id: 'system', content: '⚙️ System', style: 'background-color: #ffeee1;' },
               'image': { id: 'image', content: '🖼️ Image', style: 'background-color: #e1f5fe;' },
-              'sidechain': { id: 'sidechain', content: '🔗 Sub-assistant', style: 'background-color: #f5f5f5;' }
+              'sidechain': { id: 'sidechain', content: '🔗 Sub-assistant', style: 'background-color: #f5f5f5;' },
+              'slash-command': { id: 'slash-command', content: '⌨️ Slash Command', style: 'background-color: #e8eaf6;' },
+              'command-output': { id: 'command-output', content: '📋 Command Output', style: 'background-color: #efebe9;' },
+              'bash-input': { id: 'bash-input', content: '💻 Bash Input', style: 'background-color: #e8eaf6;' },
+              'bash-output': { id: 'bash-output', content: '📄 Bash Output', style: 'background-color: #efebe9;' }
           };
   
           // Build timeline data from messages
@@ -9078,6 +9140,14 @@
                       messageType = 'sidechain';
                   } else if (classList.includes('system-warning') || classList.includes('system-error') || classList.includes('system-info')) {
                       messageType = 'system';
+                  } else if (classList.includes('slash-command')) {
+                      messageType = 'slash-command';
+                  } else if (classList.includes('command-output')) {
+                      messageType = 'command-output';
+                  } else if (classList.includes('bash-input')) {
+                      messageType = 'bash-input';
+                  } else if (classList.includes('bash-output')) {
+                      messageType = 'bash-output';
                   } else {
                       // Look for standard message types
                       messageType = classList.find(cls =>
@@ -9202,10 +9272,15 @@
               const activeTypes = Array.from(document.querySelectorAll('.filter-toggle.active'))
                   .map(toggle => toggle.dataset.type);
   
+              // Get all filter toggle types (to know which groups have filter controls)
+              const allFilterTypes = Array.from(document.querySelectorAll('.filter-toggle'))
+                  .map(toggle => toggle.dataset.type);
+  
               // Update groups visibility based on filter states
+              // Groups with filter toggles follow toggle state; groups without toggles stay visible
               const updatedGroups = groups.map(group => ({
                   ...group,
-                  visible: activeTypes.includes(group.id)
+                  visible: allFilterTypes.includes(group.id) ? activeTypes.includes(group.id) : true
               }));
   
               // Update timeline groups
@@ -9283,7 +9358,7 @@
                       axis: 2
                   },
                   groupOrder: (a, b) => {
-                      const order = ['user', 'assistant', 'sidechain', 'tool_use', 'tool_result', 'thinking', 'system', 'image'];
+                      const order = ['user', 'system', 'slash-command', 'command-output', 'bash-input', 'bash-output', 'thinking', 'assistant', 'sidechain', 'tool_use', 'tool_result', 'image'];
                       return order.indexOf(a.id) - order.indexOf(b.id);
                   }
               };
@@ -9759,7 +9834,7 @@
       
       <div class='message user command-output pair_last session-edge_cases' data-message-id='d-6' id='msg-d-6-last'>
           <div class='header'>
-              <span>🤷 Command Output</span>
+              <span>Command output</span>
               <div class='header-info'>
                   <div class='timestamp-row'>
                       <span class='timestamp' data-timestamp='2025-06-14T11:02:20Z'>2025-06-14 11:02:20</span>
@@ -10185,7 +10260,7 @@
   
               // Count messages by type and update button labels
               function updateMessageCounts() {
-                  const messageTypes = ['user', 'assistant', 'sidechain', 'system', 'thinking', 'image'];
+                  const messageTypes = ['assistant', 'sidechain', 'system', 'thinking', 'image'];
   
                   messageTypes.forEach(type => {
                       const messages = document.querySelectorAll(`.message.${type}:not(.session-header)`);
@@ -10205,8 +10280,23 @@
                       }
                   });
   
-                  // Handle combined "tool" filter (tool_use + tool_result + bash messages)
-                  const toolMessages = document.querySelectorAll(`.message.tool_use:not(.session-header), .message.tool_result:not(.session-header), .message.bash-input:not(.session-header), .message.bash-output:not(.session-header)`);
+                  // Handle combined "user" filter (user + bash-input + bash-output)
+                  const userMessages = document.querySelectorAll(`.message.user:not(.session-header), .message.bash-input:not(.session-header), .message.bash-output:not(.session-header)`);
+                  const userCount = userMessages.length;
+                  const userToggle = document.querySelector(`[data-type="user"]`);
+                  const userCountSpan = userToggle ? userToggle.querySelector('.count') : null;
+  
+                  if (userCountSpan) {
+                      userCountSpan.textContent = `(${userCount})`;
+                      if (userCount === 0) {
+                          userToggle.style.display = 'none';
+                      } else {
+                          userToggle.style.display = 'flex';
+                      }
+                  }
+  
+                  // Handle combined "tool" filter (tool_use + tool_result)
+                  const toolMessages = document.querySelectorAll(`.message.tool_use:not(.session-header), .message.tool_result:not(.session-header)`);
                   const toolCount = toolMessages.length;
                   const toolToggle = document.querySelector(`[data-type="tool"]`);
                   const toolCountSpan = toolToggle ? toolToggle.querySelector('.count') : null;
@@ -10227,11 +10317,14 @@
                       .filter(toggle => toggle.classList.contains('active'))
                       .map(toggle => toggle.dataset.type);
   
-                  // Expand "tool" to include tool_use, tool_result, and bash messages
+                  // Expand filter types to their corresponding CSS classes
                   const expandedTypes = [];
                   activeTypes.forEach(type => {
                       if (type === 'tool') {
-                          expandedTypes.push('tool_use', 'tool_result', 'bash-input', 'bash-output');
+                          expandedTypes.push('tool_use', 'tool_result');
+                      } else if (type === 'user') {
+                          // User filter includes bash commands (user-initiated)
+                          expandedTypes.push('user', 'bash-input', 'bash-output');
                       } else {
                           expandedTypes.push(type);
                       }
@@ -10275,7 +10368,7 @@
               }
   
               function updateVisibleCounts() {
-                  const messageTypes = ['user', 'assistant', 'sidechain', 'system', 'thinking', 'image'];
+                  const messageTypes = ['assistant', 'sidechain', 'system', 'thinking', 'image'];
   
                   messageTypes.forEach(type => {
                       const visibleMessages = document.querySelectorAll(`.message.${type}:not(.session-header):not(.filtered-hidden)`);
@@ -10302,9 +10395,32 @@
                       }
                   });
   
-                  // Handle combined "tool" filter separately (includes bash messages)
-                  const visibleToolMessages = document.querySelectorAll(`.message.tool_use:not(.session-header):not(.filtered-hidden), .message.tool_result:not(.session-header):not(.filtered-hidden), .message.bash-input:not(.session-header):not(.filtered-hidden), .message.bash-output:not(.session-header):not(.filtered-hidden)`);
-                  const totalToolMessages = document.querySelectorAll(`.message.tool_use:not(.session-header), .message.tool_result:not(.session-header), .message.bash-input:not(.session-header), .message.bash-output:not(.session-header)`);
+                  // Handle combined "user" filter separately (includes bash messages)
+                  const visibleUserMessages = document.querySelectorAll(`.message.user:not(.session-header):not(.filtered-hidden), .message.bash-input:not(.session-header):not(.filtered-hidden), .message.bash-output:not(.session-header):not(.filtered-hidden)`);
+                  const totalUserMessages = document.querySelectorAll(`.message.user:not(.session-header), .message.bash-input:not(.session-header), .message.bash-output:not(.session-header)`);
+                  const visibleUserCount = visibleUserMessages.length;
+                  const totalUserCount = totalUserMessages.length;
+  
+                  const userToggle = document.querySelector(`[data-type="user"]`);
+                  const userCountSpan = userToggle ? userToggle.querySelector('.count') : null;
+  
+                  if (userCountSpan && totalUserCount > 0) {
+                      const activeTypes = Array.from(filterToggles)
+                          .filter(toggle => toggle.classList.contains('active'))
+                          .map(toggle => toggle.dataset.type);
+  
+                      const isFiltering = activeTypes.length < filterToggles.length;
+  
+                      if (isFiltering && visibleUserCount !== totalUserCount) {
+                          userCountSpan.textContent = `(${visibleUserCount}/${totalUserCount})`;
+                      } else {
+                          userCountSpan.textContent = `(${totalUserCount})`;
+                      }
+                  }
+  
+                  // Handle combined "tool" filter separately
+                  const visibleToolMessages = document.querySelectorAll(`.message.tool_use:not(.session-header):not(.filtered-hidden), .message.tool_result:not(.session-header):not(.filtered-hidden)`);
+                  const totalToolMessages = document.querySelectorAll(`.message.tool_use:not(.session-header), .message.tool_result:not(.session-header)`);
                   const visibleToolCount = visibleToolMessages.length;
                   const totalToolCount = totalToolMessages.length;
   
@@ -13878,7 +13994,11 @@
               'thinking': { id: 'thinking', content: '💭 Thinking', style: 'background-color: #fce4ec;' },
               'system': { id: 'system', content: '⚙️ System', style: 'background-color: #ffeee1;' },
               'image': { id: 'image', content: '🖼️ Image', style: 'background-color: #e1f5fe;' },
-              'sidechain': { id: 'sidechain', content: '🔗 Sub-assistant', style: 'background-color: #f5f5f5;' }
+              'sidechain': { id: 'sidechain', content: '🔗 Sub-assistant', style: 'background-color: #f5f5f5;' },
+              'slash-command': { id: 'slash-command', content: '⌨️ Slash Command', style: 'background-color: #e8eaf6;' },
+              'command-output': { id: 'command-output', content: '📋 Command Output', style: 'background-color: #efebe9;' },
+              'bash-input': { id: 'bash-input', content: '💻 Bash Input', style: 'background-color: #e8eaf6;' },
+              'bash-output': { id: 'bash-output', content: '📄 Bash Output', style: 'background-color: #efebe9;' }
           };
   
           // Build timeline data from messages
@@ -13904,6 +14024,14 @@
                       messageType = 'sidechain';
                   } else if (classList.includes('system-warning') || classList.includes('system-error') || classList.includes('system-info')) {
                       messageType = 'system';
+                  } else if (classList.includes('slash-command')) {
+                      messageType = 'slash-command';
+                  } else if (classList.includes('command-output')) {
+                      messageType = 'command-output';
+                  } else if (classList.includes('bash-input')) {
+                      messageType = 'bash-input';
+                  } else if (classList.includes('bash-output')) {
+                      messageType = 'bash-output';
                   } else {
                       // Look for standard message types
                       messageType = classList.find(cls =>
@@ -14028,10 +14156,15 @@
               const activeTypes = Array.from(document.querySelectorAll('.filter-toggle.active'))
                   .map(toggle => toggle.dataset.type);
   
+              // Get all filter toggle types (to know which groups have filter controls)
+              const allFilterTypes = Array.from(document.querySelectorAll('.filter-toggle'))
+                  .map(toggle => toggle.dataset.type);
+  
               // Update groups visibility based on filter states
+              // Groups with filter toggles follow toggle state; groups without toggles stay visible
               const updatedGroups = groups.map(group => ({
                   ...group,
-                  visible: activeTypes.includes(group.id)
+                  visible: allFilterTypes.includes(group.id) ? activeTypes.includes(group.id) : true
               }));
   
               // Update timeline groups
@@ -14109,7 +14242,7 @@
                       axis: 2
                   },
                   groupOrder: (a, b) => {
-                      const order = ['user', 'assistant', 'sidechain', 'tool_use', 'tool_result', 'thinking', 'system', 'image'];
+                      const order = ['user', 'system', 'slash-command', 'command-output', 'bash-input', 'bash-output', 'thinking', 'assistant', 'sidechain', 'tool_use', 'tool_result', 'image'];
                       return order.indexOf(a.id) - order.indexOf(b.id);
                   }
               };
@@ -15059,7 +15192,7 @@
   
               // Count messages by type and update button labels
               function updateMessageCounts() {
-                  const messageTypes = ['user', 'assistant', 'sidechain', 'system', 'thinking', 'image'];
+                  const messageTypes = ['assistant', 'sidechain', 'system', 'thinking', 'image'];
   
                   messageTypes.forEach(type => {
                       const messages = document.querySelectorAll(`.message.${type}:not(.session-header)`);
@@ -15079,8 +15212,23 @@
                       }
                   });
   
-                  // Handle combined "tool" filter (tool_use + tool_result + bash messages)
-                  const toolMessages = document.querySelectorAll(`.message.tool_use:not(.session-header), .message.tool_result:not(.session-header), .message.bash-input:not(.session-header), .message.bash-output:not(.session-header)`);
+                  // Handle combined "user" filter (user + bash-input + bash-output)
+                  const userMessages = document.querySelectorAll(`.message.user:not(.session-header), .message.bash-input:not(.session-header), .message.bash-output:not(.session-header)`);
+                  const userCount = userMessages.length;
+                  const userToggle = document.querySelector(`[data-type="user"]`);
+                  const userCountSpan = userToggle ? userToggle.querySelector('.count') : null;
+  
+                  if (userCountSpan) {
+                      userCountSpan.textContent = `(${userCount})`;
+                      if (userCount === 0) {
+                          userToggle.style.display = 'none';
+                      } else {
+                          userToggle.style.display = 'flex';
+                      }
+                  }
+  
+                  // Handle combined "tool" filter (tool_use + tool_result)
+                  const toolMessages = document.querySelectorAll(`.message.tool_use:not(.session-header), .message.tool_result:not(.session-header)`);
                   const toolCount = toolMessages.length;
                   const toolToggle = document.querySelector(`[data-type="tool"]`);
                   const toolCountSpan = toolToggle ? toolToggle.querySelector('.count') : null;
@@ -15101,11 +15249,14 @@
                       .filter(toggle => toggle.classList.contains('active'))
                       .map(toggle => toggle.dataset.type);
   
-                  // Expand "tool" to include tool_use, tool_result, and bash messages
+                  // Expand filter types to their corresponding CSS classes
                   const expandedTypes = [];
                   activeTypes.forEach(type => {
                       if (type === 'tool') {
-                          expandedTypes.push('tool_use', 'tool_result', 'bash-input', 'bash-output');
+                          expandedTypes.push('tool_use', 'tool_result');
+                      } else if (type === 'user') {
+                          // User filter includes bash commands (user-initiated)
+                          expandedTypes.push('user', 'bash-input', 'bash-output');
                       } else {
                           expandedTypes.push(type);
                       }
@@ -15149,7 +15300,7 @@
               }
   
               function updateVisibleCounts() {
-                  const messageTypes = ['user', 'assistant', 'sidechain', 'system', 'thinking', 'image'];
+                  const messageTypes = ['assistant', 'sidechain', 'system', 'thinking', 'image'];
   
                   messageTypes.forEach(type => {
                       const visibleMessages = document.querySelectorAll(`.message.${type}:not(.session-header):not(.filtered-hidden)`);
@@ -15176,9 +15327,32 @@
                       }
                   });
   
-                  // Handle combined "tool" filter separately (includes bash messages)
-                  const visibleToolMessages = document.querySelectorAll(`.message.tool_use:not(.session-header):not(.filtered-hidden), .message.tool_result:not(.session-header):not(.filtered-hidden), .message.bash-input:not(.session-header):not(.filtered-hidden), .message.bash-output:not(.session-header):not(.filtered-hidden)`);
-                  const totalToolMessages = document.querySelectorAll(`.message.tool_use:not(.session-header), .message.tool_result:not(.session-header), .message.bash-input:not(.session-header), .message.bash-output:not(.session-header)`);
+                  // Handle combined "user" filter separately (includes bash messages)
+                  const visibleUserMessages = document.querySelectorAll(`.message.user:not(.session-header):not(.filtered-hidden), .message.bash-input:not(.session-header):not(.filtered-hidden), .message.bash-output:not(.session-header):not(.filtered-hidden)`);
+                  const totalUserMessages = document.querySelectorAll(`.message.user:not(.session-header), .message.bash-input:not(.session-header), .message.bash-output:not(.session-header)`);
+                  const visibleUserCount = visibleUserMessages.length;
+                  const totalUserCount = totalUserMessages.length;
+  
+                  const userToggle = document.querySelector(`[data-type="user"]`);
+                  const userCountSpan = userToggle ? userToggle.querySelector('.count') : null;
+  
+                  if (userCountSpan && totalUserCount > 0) {
+                      const activeTypes = Array.from(filterToggles)
+                          .filter(toggle => toggle.classList.contains('active'))
+                          .map(toggle => toggle.dataset.type);
+  
+                      const isFiltering = activeTypes.length < filterToggles.length;
+  
+                      if (isFiltering && visibleUserCount !== totalUserCount) {
+                          userCountSpan.textContent = `(${visibleUserCount}/${totalUserCount})`;
+                      } else {
+                          userCountSpan.textContent = `(${totalUserCount})`;
+                      }
+                  }
+  
+                  // Handle combined "tool" filter separately
+                  const visibleToolMessages = document.querySelectorAll(`.message.tool_use:not(.session-header):not(.filtered-hidden), .message.tool_result:not(.session-header):not(.filtered-hidden)`);
+                  const totalToolMessages = document.querySelectorAll(`.message.tool_use:not(.session-header), .message.tool_result:not(.session-header)`);
                   const visibleToolCount = visibleToolMessages.length;
                   const totalToolCount = totalToolMessages.length;
   
@@ -18752,7 +18926,11 @@
               'thinking': { id: 'thinking', content: '💭 Thinking', style: 'background-color: #fce4ec;' },
               'system': { id: 'system', content: '⚙️ System', style: 'background-color: #ffeee1;' },
               'image': { id: 'image', content: '🖼️ Image', style: 'background-color: #e1f5fe;' },
-              'sidechain': { id: 'sidechain', content: '🔗 Sub-assistant', style: 'background-color: #f5f5f5;' }
+              'sidechain': { id: 'sidechain', content: '🔗 Sub-assistant', style: 'background-color: #f5f5f5;' },
+              'slash-command': { id: 'slash-command', content: '⌨️ Slash Command', style: 'background-color: #e8eaf6;' },
+              'command-output': { id: 'command-output', content: '📋 Command Output', style: 'background-color: #efebe9;' },
+              'bash-input': { id: 'bash-input', content: '💻 Bash Input', style: 'background-color: #e8eaf6;' },
+              'bash-output': { id: 'bash-output', content: '📄 Bash Output', style: 'background-color: #efebe9;' }
           };
   
           // Build timeline data from messages
@@ -18778,6 +18956,14 @@
                       messageType = 'sidechain';
                   } else if (classList.includes('system-warning') || classList.includes('system-error') || classList.includes('system-info')) {
                       messageType = 'system';
+                  } else if (classList.includes('slash-command')) {
+                      messageType = 'slash-command';
+                  } else if (classList.includes('command-output')) {
+                      messageType = 'command-output';
+                  } else if (classList.includes('bash-input')) {
+                      messageType = 'bash-input';
+                  } else if (classList.includes('bash-output')) {
+                      messageType = 'bash-output';
                   } else {
                       // Look for standard message types
                       messageType = classList.find(cls =>
@@ -18902,10 +19088,15 @@
               const activeTypes = Array.from(document.querySelectorAll('.filter-toggle.active'))
                   .map(toggle => toggle.dataset.type);
   
+              // Get all filter toggle types (to know which groups have filter controls)
+              const allFilterTypes = Array.from(document.querySelectorAll('.filter-toggle'))
+                  .map(toggle => toggle.dataset.type);
+  
               // Update groups visibility based on filter states
+              // Groups with filter toggles follow toggle state; groups without toggles stay visible
               const updatedGroups = groups.map(group => ({
                   ...group,
-                  visible: activeTypes.includes(group.id)
+                  visible: allFilterTypes.includes(group.id) ? activeTypes.includes(group.id) : true
               }));
   
               // Update timeline groups
@@ -18983,7 +19174,7 @@
                       axis: 2
                   },
                   groupOrder: (a, b) => {
-                      const order = ['user', 'assistant', 'sidechain', 'tool_use', 'tool_result', 'thinking', 'system', 'image'];
+                      const order = ['user', 'system', 'slash-command', 'command-output', 'bash-input', 'bash-output', 'thinking', 'assistant', 'sidechain', 'tool_use', 'tool_result', 'image'];
                       return order.indexOf(a.id) - order.indexOf(b.id);
                   }
               };
@@ -19795,7 +19986,7 @@
   
               // Count messages by type and update button labels
               function updateMessageCounts() {
-                  const messageTypes = ['user', 'assistant', 'sidechain', 'system', 'thinking', 'image'];
+                  const messageTypes = ['assistant', 'sidechain', 'system', 'thinking', 'image'];
   
                   messageTypes.forEach(type => {
                       const messages = document.querySelectorAll(`.message.${type}:not(.session-header)`);
@@ -19815,8 +20006,23 @@
                       }
                   });
   
-                  // Handle combined "tool" filter (tool_use + tool_result + bash messages)
-                  const toolMessages = document.querySelectorAll(`.message.tool_use:not(.session-header), .message.tool_result:not(.session-header), .message.bash-input:not(.session-header), .message.bash-output:not(.session-header)`);
+                  // Handle combined "user" filter (user + bash-input + bash-output)
+                  const userMessages = document.querySelectorAll(`.message.user:not(.session-header), .message.bash-input:not(.session-header), .message.bash-output:not(.session-header)`);
+                  const userCount = userMessages.length;
+                  const userToggle = document.querySelector(`[data-type="user"]`);
+                  const userCountSpan = userToggle ? userToggle.querySelector('.count') : null;
+  
+                  if (userCountSpan) {
+                      userCountSpan.textContent = `(${userCount})`;
+                      if (userCount === 0) {
+                          userToggle.style.display = 'none';
+                      } else {
+                          userToggle.style.display = 'flex';
+                      }
+                  }
+  
+                  // Handle combined "tool" filter (tool_use + tool_result)
+                  const toolMessages = document.querySelectorAll(`.message.tool_use:not(.session-header), .message.tool_result:not(.session-header)`);
                   const toolCount = toolMessages.length;
                   const toolToggle = document.querySelector(`[data-type="tool"]`);
                   const toolCountSpan = toolToggle ? toolToggle.querySelector('.count') : null;
@@ -19837,11 +20043,14 @@
                       .filter(toggle => toggle.classList.contains('active'))
                       .map(toggle => toggle.dataset.type);
   
-                  // Expand "tool" to include tool_use, tool_result, and bash messages
+                  // Expand filter types to their corresponding CSS classes
                   const expandedTypes = [];
                   activeTypes.forEach(type => {
                       if (type === 'tool') {
-                          expandedTypes.push('tool_use', 'tool_result', 'bash-input', 'bash-output');
+                          expandedTypes.push('tool_use', 'tool_result');
+                      } else if (type === 'user') {
+                          // User filter includes bash commands (user-initiated)
+                          expandedTypes.push('user', 'bash-input', 'bash-output');
                       } else {
                           expandedTypes.push(type);
                       }
@@ -19885,7 +20094,7 @@
               }
   
               function updateVisibleCounts() {
-                  const messageTypes = ['user', 'assistant', 'sidechain', 'system', 'thinking', 'image'];
+                  const messageTypes = ['assistant', 'sidechain', 'system', 'thinking', 'image'];
   
                   messageTypes.forEach(type => {
                       const visibleMessages = document.querySelectorAll(`.message.${type}:not(.session-header):not(.filtered-hidden)`);
@@ -19912,9 +20121,32 @@
                       }
                   });
   
-                  // Handle combined "tool" filter separately (includes bash messages)
-                  const visibleToolMessages = document.querySelectorAll(`.message.tool_use:not(.session-header):not(.filtered-hidden), .message.tool_result:not(.session-header):not(.filtered-hidden), .message.bash-input:not(.session-header):not(.filtered-hidden), .message.bash-output:not(.session-header):not(.filtered-hidden)`);
-                  const totalToolMessages = document.querySelectorAll(`.message.tool_use:not(.session-header), .message.tool_result:not(.session-header), .message.bash-input:not(.session-header), .message.bash-output:not(.session-header)`);
+                  // Handle combined "user" filter separately (includes bash messages)
+                  const visibleUserMessages = document.querySelectorAll(`.message.user:not(.session-header):not(.filtered-hidden), .message.bash-input:not(.session-header):not(.filtered-hidden), .message.bash-output:not(.session-header):not(.filtered-hidden)`);
+                  const totalUserMessages = document.querySelectorAll(`.message.user:not(.session-header), .message.bash-input:not(.session-header), .message.bash-output:not(.session-header)`);
+                  const visibleUserCount = visibleUserMessages.length;
+                  const totalUserCount = totalUserMessages.length;
+  
+                  const userToggle = document.querySelector(`[data-type="user"]`);
+                  const userCountSpan = userToggle ? userToggle.querySelector('.count') : null;
+  
+                  if (userCountSpan && totalUserCount > 0) {
+                      const activeTypes = Array.from(filterToggles)
+                          .filter(toggle => toggle.classList.contains('active'))
+                          .map(toggle => toggle.dataset.type);
+  
+                      const isFiltering = activeTypes.length < filterToggles.length;
+  
+                      if (isFiltering && visibleUserCount !== totalUserCount) {
+                          userCountSpan.textContent = `(${visibleUserCount}/${totalUserCount})`;
+                      } else {
+                          userCountSpan.textContent = `(${totalUserCount})`;
+                      }
+                  }
+  
+                  // Handle combined "tool" filter separately
+                  const visibleToolMessages = document.querySelectorAll(`.message.tool_use:not(.session-header):not(.filtered-hidden), .message.tool_result:not(.session-header):not(.filtered-hidden)`);
+                  const totalToolMessages = document.querySelectorAll(`.message.tool_use:not(.session-header), .message.tool_result:not(.session-header)`);
                   const visibleToolCount = visibleToolMessages.length;
                   const totalToolCount = totalToolMessages.length;
   
diff --git a/test/test_ansi_colors.py b/test/test_ansi_colors.py
index 4a1da013..bb12901c 100644
--- a/test/test_ansi_colors.py
+++ b/test/test_ansi_colors.py
@@ -72,6 +72,12 @@ def test_reset_codes(self):
         result = convert_ansi_to_html(text)
         assert '<span class="ansi-bold">Bold</span> Normal' in result
 
+        # Test empty params reset form (ESC[m is equivalent to ESC[0m)
+        text = "\x1b[31mRed\x1b[m Normal"
+        result = convert_ansi_to_html(text)
+        assert '<span class="ansi-red">Red</span> Normal' in result
+        assert "\x1b" not in result  # No raw escape sequences
+
     def test_html_escaping(self):
         """Test that HTML special characters are escaped."""
         text = "\x1b[31m<script>alert('test')</script>\x1b[0m"
diff --git a/test/test_askuserquestion_rendering.py b/test/test_askuserquestion_rendering.py
index c8ac6c96..3d8a3acc 100644
--- a/test/test_askuserquestion_rendering.py
+++ b/test/test_askuserquestion_rendering.py
@@ -203,7 +203,8 @@ def test_format_askuserquestion_escapes_html(self):
         assert "&lt;script&gt;" in html
         assert "&lt;test&gt;" in html
         assert "&lt;option&gt;" in html
-        assert "&amp;amp;" in html or "& symbol" not in html
+        # Input "&amp;" should be escaped to "&amp;amp;"
+        assert "&amp;amp;" in html
 
 
 class TestAskUserQuestionResultRendering:
diff --git a/test/test_cache.py b/test/test_cache.py
index d9409ba3..9a48d0fa 100644
--- a/test/test_cache.py
+++ b/test/test_cache.py
@@ -22,6 +22,7 @@
     UserMessage,
     AssistantMessage,
     UsageInfo,
+    TextContent,
 )
 
 
@@ -59,7 +60,9 @@ def sample_entries():
             uuid="user1",
             timestamp="2023-01-01T10:00:00Z",
             type="user",
-            message=UserMessage(role="user", content="Hello"),
+            message=UserMessage(
+                role="user", content=[TextContent(type="text", text="Hello")]
+            ),
         ),
         AssistantTranscriptEntry(
             parentUuid=None,
@@ -219,7 +222,10 @@ def test_filtered_loading_with_dates(self, cache_manager, temp_project_dir):
                 uuid="user1",
                 timestamp="2023-01-01T10:00:00Z",
                 type="user",
-                message=UserMessage(role="user", content="Early message"),
+                message=UserMessage(
+                    role="user",
+                    content=[TextContent(type="text", text="Early message")],
+                ),
             ),
             UserTranscriptEntry(
                 parentUuid=None,
@@ -231,7 +237,10 @@ def test_filtered_loading_with_dates(self, cache_manager, temp_project_dir):
                 uuid="user2",
                 timestamp="2023-01-02T10:00:00Z",
                 type="user",
-                message=UserMessage(role="user", content="Later message"),
+                message=UserMessage(
+                    role="user",
+                    content=[TextContent(type="text", text="Later message")],
+                ),
             ),
         ]
 
diff --git a/test/test_date_filtering.py b/test/test_date_filtering.py
index f7dee387..722bd41d 100644
--- a/test/test_date_filtering.py
+++ b/test/test_date_filtering.py
@@ -3,7 +3,7 @@
 
 import json
 import tempfile
-from datetime import datetime, timedelta
+from datetime import datetime, timedelta, timezone
 from pathlib import Path
 from claude_code_log.converter import convert_jsonl_to_html
 from claude_code_log.converter import filter_messages_by_date
@@ -29,19 +29,21 @@ def create_test_message(timestamp_str: str, text: str) -> dict:
 def test_date_filtering():
     """Test filtering messages by date range."""
 
-    # Create test messages with different timestamps
-    today = datetime.now()
+    # Create test messages with different timestamps (use UTC for consistency)
+    today = datetime.now(timezone.utc)
     yesterday = today - timedelta(days=1)
     two_days_ago = today - timedelta(days=2)
     three_days_ago = today - timedelta(days=3)
 
+    # Format timestamps as ISO with 'Z' suffix (standard UTC format)
+    def to_utc_iso(dt: datetime) -> str:
+        return dt.strftime("%Y-%m-%dT%H:%M:%S") + "Z"
+
     message_dicts = [
-        create_test_message(
-            three_days_ago.isoformat() + "Z", "Message from 3 days ago"
-        ),
-        create_test_message(two_days_ago.isoformat() + "Z", "Message from 2 days ago"),
-        create_test_message(yesterday.isoformat() + "Z", "Message from yesterday"),
-        create_test_message(today.isoformat() + "Z", "Message from today"),
+        create_test_message(to_utc_iso(three_days_ago), "Message from 3 days ago"),
+        create_test_message(to_utc_iso(two_days_ago), "Message from 2 days ago"),
+        create_test_message(to_utc_iso(yesterday), "Message from yesterday"),
+        create_test_message(to_utc_iso(today), "Message from today"),
     ]
 
     # Parse dictionaries into TranscriptEntry objects
@@ -99,13 +101,16 @@ def test_invalid_date_handling():
 def test_end_to_end_date_filtering():
     """Test end-to-end date filtering with JSONL file."""
 
-    # Create test messages
-    today = datetime.now()
+    # Create test messages (use UTC for consistency)
+    today = datetime.now(timezone.utc)
     yesterday = today - timedelta(days=1)
 
+    def to_utc_iso(dt: datetime) -> str:
+        return dt.strftime("%Y-%m-%dT%H:%M:%S") + "Z"
+
     messages = [
-        create_test_message(yesterday.isoformat() + "Z", "Yesterday's message"),
-        create_test_message(today.isoformat() + "Z", "Today's message"),
+        create_test_message(to_utc_iso(yesterday), "Yesterday's message"),
+        create_test_message(to_utc_iso(today), "Today's message"),
     ]
 
     # Write to temporary JSONL file
diff --git a/test/test_integration_realistic.py b/test/test_integration_realistic.py
index f4d2c86e..d2b0adc4 100644
--- a/test/test_integration_realistic.py
+++ b/test/test_integration_realistic.py
@@ -739,7 +739,9 @@ def test_adding_lines_triggers_cache_update(
         if not project.exists():
             pytest.skip("JSSoundRecorder test data not available")
 
-        jsonl_files = list(project.glob("*.jsonl"))
+        jsonl_files = [
+            f for f in project.glob("*.jsonl") if not f.name.startswith("agent-")
+        ]
         if not jsonl_files:
             pytest.skip("No JSONL files available")
 
@@ -772,7 +774,9 @@ def test_adding_lines_triggers_html_regeneration(
         if not project.exists():
             pytest.skip("JSSoundRecorder test data not available")
 
-        jsonl_files = list(project.glob("*.jsonl"))
+        jsonl_files = [
+            f for f in project.glob("*.jsonl") if not f.name.startswith("agent-")
+        ]
         if not jsonl_files:
             pytest.skip("No JSONL files available")
 
@@ -803,7 +807,9 @@ def test_new_content_appears_in_html(self, projects_with_cache: Path) -> None:
         if not project.exists():
             pytest.skip("JSSoundRecorder test data not available")
 
-        jsonl_files = list(project.glob("*.jsonl"))
+        jsonl_files = [
+            f for f in project.glob("*.jsonl") if not f.name.startswith("agent-")
+        ]
         if not jsonl_files:
             pytest.skip("No JSONL files available")
 
@@ -917,7 +923,9 @@ def test_custom_output_single_file(self, temp_projects_copy: Path) -> None:
         if not project.exists():
             pytest.skip("JSSoundRecorder test data not available")
 
-        jsonl_files = list(project.glob("*.jsonl"))
+        jsonl_files = [
+            f for f in project.glob("*.jsonl") if not f.name.startswith("agent-")
+        ]
         if not jsonl_files:
             pytest.skip("No JSONL files available")
 
@@ -1104,7 +1112,9 @@ def test_index_regenerated_when_project_cache_updates(
         if not project.exists():
             pytest.skip("JSSoundRecorder test data not available")
 
-        jsonl_files = list(project.glob("*.jsonl"))
+        jsonl_files = [
+            f for f in project.glob("*.jsonl") if not f.name.startswith("agent-")
+        ]
         if not jsonl_files:
             pytest.skip("No JSONL files available")
 
@@ -1157,7 +1167,9 @@ def test_invalid_jsonl_line_handled(self, temp_projects_copy: Path) -> None:
         if not project.exists():
             pytest.skip("JSSoundRecorder test data not available")
 
-        jsonl_files = list(project.glob("*.jsonl"))
+        jsonl_files = [
+            f for f in project.glob("*.jsonl") if not f.name.startswith("agent-")
+        ]
         if not jsonl_files:
             pytest.skip("No JSONL files available")
 
@@ -1235,7 +1247,9 @@ def test_deleted_file_processing_continues(self, projects_with_cache: Path) -> N
             pytest.skip("JSSoundRecorder test data not available")
 
         # Get list of JSONL files
-        jsonl_files = list(project.glob("*.jsonl"))
+        jsonl_files = [
+            f for f in project.glob("*.jsonl") if not f.name.startswith("agent-")
+        ]
         if len(jsonl_files) < 2:
             pytest.skip("Need multiple files for deletion test")
 
diff --git a/test/test_phase8_message_variants.py b/test/test_phase8_message_variants.py
index bf1c097b..3d4da469 100644
--- a/test/test_phase8_message_variants.py
+++ b/test/test_phase8_message_variants.py
@@ -126,15 +126,12 @@ def test_slash_command_sidechain(self):
             messages = load_transcript(test_file_path)
             html = generate_html(messages, "Test Sidechain Slash Command")
 
-            # Note: Sidechain user messages are typically skipped, but isMeta ones
-            # may have different behavior. This test documents the actual behavior.
-            # The key is that if rendered, it should have both modifiers.
-
-            # If the message is rendered, check for combined CSS classes
-            if "Sub-agent Slash Command" in html:
-                assert "sidechain" in html or "slash-command" in html, (
-                    "If rendered, should have sidechain or slash-command class"
-                )
+            # Sidechain user messages without tool results are skipped during filtering
+            # (see _filter_messages in renderer.py). Even with isMeta=True, they don't
+            # contain tool results so they are not rendered.
+            assert "Sub-agent Slash Command" not in html, (
+                "Sidechain user messages without tool results should be skipped"
+            )
 
         finally:
             test_file_path.unlink()
@@ -380,11 +377,14 @@ def test_user_compacted_sidechain(self):
             messages = load_transcript(test_file_path)
             html = generate_html(messages, "Test Compacted Sidechain")
 
-            # Sidechain user messages are typically skipped, but if rendered...
-            # The presence of context-messages tag triggers compacted detection
-            if "context-messages" in html or "compacted" in html.lower():
-                # If rendered, should have both modifiers
-                pass  # Test documents behavior
+            # Sidechain user messages are skipped (duplicate of Task prompt input)
+            # Verify the raw content is not rendered
+            assert "context-messages" not in html, (
+                "Sidechain user messages should be skipped"
+            )
+            assert "[Compacted conversation]" not in html, (
+                "Sidechain user message content should not be rendered"
+            )
 
         finally:
             test_file_path.unlink()
diff --git a/test/test_renderer.py b/test/test_renderer.py
index 5c8e9a49..78c20a21 100644
--- a/test/test_renderer.py
+++ b/test/test_renderer.py
@@ -20,7 +20,7 @@ class TestRendererEdgeCases:
     """Tests for renderer.py edge cases."""
 
     def test_empty_messages_label(self):
-        """Test format_children_label with 0 messages (line 1471)."""
+        """Test that transcripts with no renderable content produce valid HTML."""
         # Create a transcript with no renderable content
         empty_message = {
             "type": "queue-operation",
diff --git a/test/test_template_utils.py b/test/test_template_utils.py
index dae6693b..196510d2 100644
--- a/test/test_template_utils.py
+++ b/test/test_template_utils.py
@@ -70,9 +70,9 @@ def test_extract_text_content_from_mixed_list(self):
         result = extract_text_content(content_items)
         assert result == "Text content\nMore text"
 
-    def test_extract_text_content_from_string(self):
-        """Test extracting text content from string."""
-        content = "Simple string content"
+    def test_extract_text_content_from_single_text_item(self):
+        """Test extracting text content from list with single text item."""
+        content = [TextContent(type="text", text="Simple string content")]
         result = extract_text_content(content)
         assert result == "Simple string content"
 
diff --git a/test/test_todowrite_rendering.py b/test/test_todowrite_rendering.py
index eaf91f51..3973269e 100644
--- a/test/test_todowrite_rendering.py
+++ b/test/test_todowrite_rendering.py
@@ -6,7 +6,7 @@
 from pathlib import Path
 import pytest
 from claude_code_log.converter import convert_jsonl_to_html
-from claude_code_log.html import format_todowrite_content
+from claude_code_log.html import format_todowrite_content, format_tool_use_content
 from claude_code_log.models import TodoWriteInput, TodoWriteItem, ToolUseContent
 
 
@@ -75,16 +75,6 @@ def test_format_todowrite_empty(self):
         # Title and ID are now in the message header, not in content
         assert "No todos found" in html
 
-    def test_format_todowrite_missing_todos(self):
-        """Test TodoWrite formatting with missing todos field."""
-        # TodoWriteInput with default empty list
-        todo_input = TodoWriteInput(todos=[])
-
-        html = format_todowrite_content(todo_input)
-
-        assert 'class="todo-content"' in html
-        assert "No todos found" in html
-
     def test_format_todowrite_html_escaping(self):
         """Test that TodoWrite content is properly HTML escaped."""
         todo_input = TodoWriteInput(
@@ -229,8 +219,6 @@ def test_todowrite_vs_regular_tool_use(self):
         )
 
         # Test both through the main format function
-        from claude_code_log.html import format_tool_use_content
-
         regular_html = format_tool_use_content(regular_tool)
         todowrite_html = format_tool_use_content(todowrite_tool)
 
diff --git a/test/test_utils.py b/test/test_utils.py
index 13dbba20..642390e8 100644
--- a/test/test_utils.py
+++ b/test/test_utils.py
@@ -268,24 +268,33 @@ def test_should_not_use_empty_string_as_starter(self):
 class TestTextContentLength:
     """Test the text content length extraction functionality."""
 
-    def test_extract_text_content_length_string(self):
-        """Test length extraction from string content."""
-        content = "Hello world, this is a test message."
-        assert extract_text_content_length(content) == len(content)
-
-    def test_extract_text_content_length_string_with_whitespace(self):
-        """Test length extraction from string with leading/trailing whitespace."""
-        content = "   Hello world   "
+    def test_extract_text_content_length_single_text_item(self):
+        """Test length extraction from list with single text item."""
+        content = [
+            TextContent(type="text", text="Hello world, this is a test message.")
+        ]
+        assert extract_text_content_length(content) == len(
+            "Hello world, this is a test message."
+        )
+
+    def test_extract_text_content_length_text_with_whitespace(self):
+        """Test length extraction from text with leading/trailing whitespace."""
+        content = [TextContent(type="text", text="   Hello world   ")]
         assert extract_text_content_length(content) == len("Hello world")
 
-    def test_extract_text_content_length_empty_string(self):
-        """Test length extraction from empty string."""
-        content = ""
+    def test_extract_text_content_length_empty_list(self):
+        """Test length extraction from empty list."""
+        content: list = []
+        assert extract_text_content_length(content) == 0
+
+    def test_extract_text_content_length_empty_text(self):
+        """Test length extraction from list with empty text."""
+        content = [TextContent(type="text", text="")]
         assert extract_text_content_length(content) == 0
 
     def test_extract_text_content_length_whitespace_only(self):
-        """Test length extraction from whitespace-only string."""
-        content = "   \n\t   "
+        """Test length extraction from text with whitespace only."""
+        content = [TextContent(type="text", text="   \n\t   ")]
         assert extract_text_content_length(content) == 0
 
     def test_extract_text_content_length_list_with_text(self):
@@ -320,11 +329,6 @@ def test_extract_text_content_length_list_no_text(self):
         content = [tool_item]
         assert extract_text_content_length(content) == 0
 
-    def test_extract_text_content_length_empty_list(self):
-        """Test length extraction from empty list."""
-        content = []
-        assert extract_text_content_length(content) == 0
-
 
 class TestEdgeCases:
     """Test edge cases and error conditions."""
@@ -617,7 +621,9 @@ def _create_user_entry(
             userType="external",
             cwd="/test",
             version="1.0.0",
-            message=UserMessage(role="user", content=content),
+            message=UserMessage(
+                role="user", content=[TextContent(type="text", text=content)]
+            ),
             uuid=uuid,
             timestamp=timestamp,
         )
@@ -748,7 +754,9 @@ def _create_user_entry(
             userType="external",
             cwd="/test",
             version="1.0.0",
-            message=UserMessage(role="user", content=content),
+            message=UserMessage(
+                role="user", content=[TextContent(type="text", text=content)]
+            ),
             uuid=uuid,
             timestamp="2025-01-01T10:00:00Z",
         )