diff --git a/CMakeLists.txt b/CMakeLists.txt
index 409a58bb..7f4a38a1 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -394,3 +394,9 @@ endif()
 # Packaging configuration
 include(cmake/packaging.cmake)
 
+add_custom_target(build_cleaner
+  COMMAND ${CMAKE_COMMAND} -E echo "Running scripts/build_cleaner.py --dry-run"
+  COMMAND ${CMAKE_COMMAND} -E chdir ${CMAKE_SOURCE_DIR} ${Python3_EXECUTABLE} scripts/build_cleaner.py --dry-run
+  COMMENT "Validate CMake source lists and includes"
+)
+
diff --git a/src/app/editor/agent/agent_chat_widget.cc b/src/app/editor/agent/agent_chat_widget.cc
index ee9a4758..68c498b5 100644
--- a/src/app/editor/agent/agent_chat_widget.cc
+++ b/src/app/editor/agent/agent_chat_widget.cc
@@ -18,6 +18,7 @@
 #include "util/file_util.h"
 #include "app/editor/agent/agent_chat_history_codec.h"
 #include "app/editor/system/proposal_drawer.h"
+#include "app/editor/system/agent_chat_history_popup.h"
 #include "app/editor/system/toast_manager.h"
 #include "app/gui/icons.h"
 #include "app/core/project.h"
@@ -122,6 +123,20 @@ void AgentChatWidget::SetProposalDrawer(ProposalDrawer* drawer) {
   }
 }
 
+void AgentChatWidget::SetChatHistoryPopup(AgentChatHistoryPopup* popup) {
+  chat_history_popup_ = popup;
+  
+  // Set up callback to open this chat window
+  if (chat_history_popup_) {
+    chat_history_popup_->SetOpenChatCallback([this]() {
+      this->set_active(true);
+    });
+    
+    // Initial sync
+    SyncHistoryToPopup();
+  }
+}
+
 void AgentChatWidget::EnsureHistoryLoaded() {
   if (history_loaded_) {
     return;
@@ -221,6 +236,9 @@ void AgentChatWidget::PersistHistory() {
   snapshot.collaboration.active = collaboration_state_.active;
   snapshot.collaboration.session_id = collaboration_state_.session_id;
   snapshot.collaboration.session_name = collaboration_state_.session_name;
+  
+  // Sync to popup when persisting
+  SyncHistoryToPopup();
   snapshot.collaboration.participants = collaboration_state_.participants;
   snapshot.collaboration.last_synced = collaboration_state_.last_synced;
   snapshot.multimodal.last_capture_path = multimodal_state_.last_capture_path;
@@ -321,6 +339,9 @@ void AgentChatWidget::HandleAgentResponse(
     NotifyProposalCreated(message, total);
   }
   last_proposal_count_ = std::max(last_proposal_count_, total);
+  
+  // Sync history to popup after response
+  SyncHistoryToPopup();
 }
 
 void AgentChatWidget::RenderMessage(const ChatMessage& msg, int index) {
@@ -1833,6 +1854,14 @@ void AgentChatWidget::HandleProposalReceived(
   }
 }
 
+void AgentChatWidget::SyncHistoryToPopup() {
+  if (!chat_history_popup_) return;
+  
+  const auto& history = agent_service_.GetHistory();
+  chat_history_popup_->UpdateHistory(history);
+  chat_history_popup_->NotifyNewMessage();
+}
+
 void AgentChatWidget::RenderSystemPromptEditor() {
   ImGui::BeginChild("SystemPromptEditor", ImVec2(0, 0), false);
   
diff --git a/src/app/editor/agent/agent_chat_widget.h b/src/app/editor/agent/agent_chat_widget.h
index e880df93..845e6321 100644
--- a/src/app/editor/agent/agent_chat_widget.h
+++ b/src/app/editor/agent/agent_chat_widget.h
@@ -25,6 +25,7 @@ namespace editor {
 
 class ProposalDrawer;
 class ToastManager;
+class AgentChatHistoryPopup;
 
 /**
  * @class AgentChatWidget
@@ -86,6 +87,8 @@ class AgentChatWidget {
   void SetToastManager(ToastManager* toast_manager);
 
   void SetProposalDrawer(ProposalDrawer* drawer);
+  
+  void SetChatHistoryPopup(AgentChatHistoryPopup* popup);
 
   void SetCollaborationCallbacks(const CollaborationCallbacks& callbacks) {
     collaboration_callbacks_ = callbacks;
@@ -228,6 +231,9 @@ public:
   void HandleRomSyncReceived(const std::string& diff_data, const std::string& rom_hash);
   void HandleSnapshotReceived(const std::string& snapshot_data, const std::string& snapshot_type);
   void HandleProposalReceived(const std::string& proposal_data);
+  
+  // History synchronization
+  void SyncHistoryToPopup();
 
   // Chat session management
   struct ChatSession {
@@ -261,6 +267,7 @@ public:
   int last_proposal_count_ = 0;
   ToastManager* toast_manager_ = nullptr;
   ProposalDrawer* proposal_drawer_ = nullptr;
+  AgentChatHistoryPopup* chat_history_popup_ = nullptr;
   std::string pending_focus_proposal_id_;
   absl::Time last_persist_time_ = absl::InfinitePast();
   
diff --git a/src/app/editor/editor_library.cmake b/src/app/editor/editor_library.cmake
index bed17837..e007aefd 100644
--- a/src/app/editor/editor_library.cmake
+++ b/src/app/editor/editor_library.cmake
@@ -41,6 +41,7 @@ set(
   app/editor/system/shortcut_manager.cc
   app/editor/system/popup_manager.cc
   app/editor/system/proposal_drawer.cc
+  app/editor/system/agent_chat_history_popup.cc
   app/editor/agent/agent_chat_history_codec.cc
 )
 
diff --git a/src/app/editor/system/agent_chat_history_popup.cc b/src/app/editor/system/agent_chat_history_popup.cc
new file mode 100644
index 00000000..d0fedaa2
--- /dev/null
+++ b/src/app/editor/system/agent_chat_history_popup.cc
@@ -0,0 +1,231 @@
+#include "app/editor/system/agent_chat_history_popup.h"
+
+#include "absl/strings/str_format.h"
+#include "absl/time/time.h"
+#include "imgui/imgui.h"
+#include "app/gui/icons.h"
+#include "app/editor/system/toast_manager.h"
+
+namespace yaze {
+namespace editor {
+
+namespace {
+
+const ImVec4 kUserColor = ImVec4(0.88f, 0.76f, 0.36f, 1.0f);
+const ImVec4 kAgentColor = ImVec4(0.56f, 0.82f, 0.62f, 1.0f);
+const ImVec4 kTimestampColor = ImVec4(0.6f, 0.6f, 0.6f, 1.0f);
+
+}  // namespace
+
+AgentChatHistoryPopup::AgentChatHistoryPopup() {}
+
+void AgentChatHistoryPopup::Draw() {
+  if (!visible_) return;
+
+  // Set drawer position on the LEFT side
+  ImGuiIO& io = ImGui::GetIO();
+  ImGui::SetNextWindowPos(ImVec2(0, 0), ImGuiCond_Always);
+  ImGui::SetNextWindowSize(ImVec2(drawer_width_, io.DisplaySize.y), 
+                           ImGuiCond_Always);
+
+  ImGuiWindowFlags flags = ImGuiWindowFlags_NoMove | 
+                          ImGuiWindowFlags_NoResize |
+                          ImGuiWindowFlags_NoCollapse;
+
+  ImGui::PushStyleColor(ImGuiCol_WindowBg, ImVec4(0.08f, 0.08f, 0.10f, 0.95f));
+  
+  if (ImGui::Begin(ICON_MD_CHAT " Chat History", &visible_, flags)) {
+    // Header with controls
+    if (ImGui::Button(ICON_MD_OPEN_IN_NEW " Open Full Chat")) {
+      if (open_chat_callback_) {
+        open_chat_callback_();
+      }
+    }
+    
+    ImGui::SameLine();
+    if (ImGui::Button(ICON_MD_REFRESH " Refresh")) {
+      // Trigger external refresh through callback
+      if (toast_manager_) {
+        toast_manager_->Show("Refreshing chat history...", ToastType::kInfo, 1.5f);
+      }
+    }
+    
+    ImGui::Separator();
+    
+    // Filter dropdown
+    const char* filter_labels[] = {"All Messages", "User Only", "Agent Only"};
+    int current_filter = static_cast<int>(message_filter_);
+    ImGui::SetNextItemWidth(-1);
+    if (ImGui::Combo("##filter", &current_filter, filter_labels, 3)) {
+      message_filter_ = static_cast<MessageFilter>(current_filter);
+    }
+    
+    ImGui::Spacing();
+    
+    // Auto-scroll checkbox
+    ImGui::Checkbox("Auto-scroll", &auto_scroll_);
+    
+    ImGui::Separator();
+    
+    // Message count indicator
+    int visible_count = 0;
+    for (const auto& msg : messages_) {
+      if (msg.is_internal) continue;
+      if (message_filter_ == MessageFilter::kUserOnly && 
+          msg.sender != cli::agent::ChatMessage::Sender::kUser) continue;
+      if (message_filter_ == MessageFilter::kAgentOnly && 
+          msg.sender != cli::agent::ChatMessage::Sender::kAgent) continue;
+      visible_count++;
+    }
+    
+    ImGui::TextColored(ImVec4(0.7f, 0.7f, 0.7f, 1.0f), 
+                      "%d message%s", visible_count, visible_count == 1 ? "" : "s");
+    
+    ImGui::Separator();
+    
+    // Message list
+    ImGui::BeginChild("MessageList", ImVec2(0, -45), true);
+    DrawMessageList();
+    
+    if (needs_scroll_) {
+      ImGui::SetScrollHereY(1.0f);
+      needs_scroll_ = false;
+    }
+    
+    ImGui::EndChild();
+    
+    // Action buttons at bottom
+    ImGui::Separator();
+    DrawActionButtons();
+  }
+  ImGui::End();
+  
+  ImGui::PopStyleColor();
+}
+
+void AgentChatHistoryPopup::DrawMessageList() {
+  if (messages_.empty()) {
+    ImGui::TextDisabled("No messages yet. Start a conversation in the chat window.");
+    return;
+  }
+  
+  // Calculate starting index for display limit
+  int start_index = messages_.size() > display_limit_ ? 
+                    messages_.size() - display_limit_ : 0;
+  
+  for (int i = start_index; i < messages_.size(); ++i) {
+    const auto& msg = messages_[i];
+    
+    // Skip internal messages
+    if (msg.is_internal) continue;
+    
+    // Apply filter
+    if (message_filter_ == MessageFilter::kUserOnly && 
+        msg.sender != cli::agent::ChatMessage::Sender::kUser) continue;
+    if (message_filter_ == MessageFilter::kAgentOnly && 
+        msg.sender != cli::agent::ChatMessage::Sender::kAgent) continue;
+    
+    DrawMessage(msg, i);
+  }
+}
+
+void AgentChatHistoryPopup::DrawMessage(const cli::agent::ChatMessage& msg, int index) {
+  ImGui::PushID(index);
+  
+  bool from_user = (msg.sender == cli::agent::ChatMessage::Sender::kUser);
+  ImVec4 header_color = from_user ? kUserColor : kAgentColor;
+  const char* sender_label = from_user ? ICON_MD_PERSON " You" : ICON_MD_SMART_TOY " Agent";
+  
+  // Message header with sender and timestamp
+  ImGui::PushStyleColor(ImGuiCol_Text, header_color);
+  ImGui::Text("%s", sender_label);
+  ImGui::PopStyleColor();
+  
+  ImGui::SameLine();
+  ImGui::PushStyleColor(ImGuiCol_Text, kTimestampColor);
+  ImGui::Text("%s", absl::FormatTime("%H:%M:%S", msg.timestamp, absl::LocalTimeZone()).c_str());
+  ImGui::PopStyleColor();
+  
+  // Message content
+  ImGui::Indent(10.0f);
+  
+  if (msg.table_data.has_value()) {
+    ImGui::TextColored(ImVec4(0.7f, 0.7f, 0.9f, 1.0f), ICON_MD_TABLE_CHART " [Table Data]");
+  } else if (msg.json_pretty.has_value()) {
+    ImGui::TextColored(ImVec4(0.7f, 0.7f, 0.9f, 1.0f), ICON_MD_DATA_OBJECT " [Structured Response]");
+  } else {
+    // Truncate long messages
+    std::string content = msg.message;
+    if (content.length() > 200) {
+      content = content.substr(0, 197) + "...";
+    }
+    ImGui::TextWrapped("%s", content.c_str());
+  }
+  
+  // Show proposal indicator if present
+  if (msg.proposal.has_value()) {
+    ImGui::TextColored(ImVec4(0.2f, 0.8f, 0.4f, 1.0f), 
+                      ICON_MD_PREVIEW " Proposal: %s", msg.proposal->id.c_str());
+  }
+  
+  ImGui::Unindent(10.0f);
+  ImGui::Spacing();
+  ImGui::Separator();
+  
+  ImGui::PopID();
+}
+
+void AgentChatHistoryPopup::DrawActionButtons() {
+  if (ImGui::Button(ICON_MD_DELETE " Clear History", ImVec2(-1, 0))) {
+    ClearHistory();
+  }
+  
+  if (ImGui::IsItemHovered()) {
+    ImGui::SetTooltip("Clear all messages from the popup view\n(Full history preserved in chat window)");
+  }
+}
+
+void AgentChatHistoryPopup::UpdateHistory(const std::vector<cli::agent::ChatMessage>& history) {
+  bool had_messages = !messages_.empty();
+  int old_size = messages_.size();
+  
+  messages_ = history;
+  
+  // Auto-scroll if new messages arrived
+  if (auto_scroll_ && messages_.size() > old_size) {
+    needs_scroll_ = true;
+  }
+}
+
+void AgentChatHistoryPopup::NotifyNewMessage() {
+  if (auto_scroll_) {
+    needs_scroll_ = true;
+  }
+  
+  // Flash the window to draw attention
+  if (toast_manager_ && !visible_) {
+    toast_manager_->Show(ICON_MD_CHAT " New message received", ToastType::kInfo, 2.0f);
+  }
+}
+
+void AgentChatHistoryPopup::ClearHistory() {
+  messages_.clear();
+  
+  if (toast_manager_) {
+    toast_manager_->Show("Chat history popup cleared", ToastType::kInfo, 2.0f);
+  }
+}
+
+void AgentChatHistoryPopup::ExportHistory() {
+  // TODO: Implement export functionality
+  if (toast_manager_) {
+    toast_manager_->Show("Export feature coming soon", ToastType::kInfo, 2.0f);
+  }
+}
+
+void AgentChatHistoryPopup::ScrollToBottom() {
+  needs_scroll_ = true;
+}
+
+}  // namespace editor
+}  // namespace yaze
diff --git a/src/app/editor/system/agent_chat_history_popup.h b/src/app/editor/system/agent_chat_history_popup.h
new file mode 100644
index 00000000..c095af14
--- /dev/null
+++ b/src/app/editor/system/agent_chat_history_popup.h
@@ -0,0 +1,98 @@
+#ifndef YAZE_APP_EDITOR_SYSTEM_AGENT_CHAT_HISTORY_POPUP_H
+#define YAZE_APP_EDITOR_SYSTEM_AGENT_CHAT_HISTORY_POPUP_H
+
+#include <string>
+#include <vector>
+
+#include "cli/service/agent/conversational_agent_service.h"
+
+namespace yaze {
+namespace editor {
+
+class ToastManager;
+
+/**
+ * @class AgentChatHistoryPopup
+ * @brief ImGui popup drawer for displaying chat history on the left side
+ * 
+ * Provides a quick-access sidebar for viewing recent chat messages,
+ * complementing the ProposalDrawer on the right. Features:
+ * - Recent message list with timestamps
+ * - User/Agent message differentiation
+ * - Scroll to view older messages
+ * - Quick actions (clear, export, open full chat)
+ * - Syncs with AgentChatWidget and AgentEditor
+ * 
+ * Positioned on the LEFT side of the screen as a slide-out panel.
+ */
+class AgentChatHistoryPopup {
+ public:
+  AgentChatHistoryPopup();
+  ~AgentChatHistoryPopup() = default;
+
+  // Set dependencies
+  void SetToastManager(ToastManager* toast_manager) {
+    toast_manager_ = toast_manager;
+  }
+
+  // Render the popup UI
+  void Draw();
+
+  // Show/hide the popup
+  void Show() { visible_ = true; }
+  void Hide() { visible_ = false; }
+  void Toggle() { visible_ = !visible_; }
+  bool IsVisible() const { return visible_; }
+
+  // Update history from service
+  void UpdateHistory(const std::vector<cli::agent::ChatMessage>& history);
+  
+  // Notify of new message (triggers auto-scroll)
+  void NotifyNewMessage();
+
+  // Set callback for opening full chat window
+  using OpenChatCallback = std::function<void()>;
+  void SetOpenChatCallback(OpenChatCallback callback) {
+    open_chat_callback_ = std::move(callback);
+  }
+
+ private:
+  void DrawMessageList();
+  void DrawMessage(const cli::agent::ChatMessage& msg, int index);
+  void DrawActionButtons();
+  
+  void ClearHistory();
+  void ExportHistory();
+  void ScrollToBottom();
+  
+  bool visible_ = false;
+  bool needs_scroll_ = false;
+  bool auto_scroll_ = true;
+  
+  // History state
+  std::vector<cli::agent::ChatMessage> messages_;
+  int display_limit_ = 50;  // Show last 50 messages
+  
+  // UI state
+  float drawer_width_ = 400.0f;
+  float min_drawer_width_ = 300.0f;
+  float max_drawer_width_ = 600.0f;
+  bool is_resizing_ = false;
+  
+  // Filter state
+  enum class MessageFilter {
+    kAll,
+    kUserOnly,
+    kAgentOnly
+  };
+  MessageFilter message_filter_ = MessageFilter::kAll;
+  
+  // Dependencies
+  ToastManager* toast_manager_ = nullptr;
+  OpenChatCallback open_chat_callback_;
+};
+
+}  // namespace editor
+}  // namespace yaze
+
+#endif  // YAZE_APP_EDITOR_SYSTEM_AGENT_CHAT_HISTORY_POPUP_H