diff --git a/src/tools/ecode/plugins/aiassistant/acp/acpclient.cpp b/src/tools/ecode/plugins/aiassistant/acp/acpclient.cpp
index 3900064e8..c02af7512 100644
--- a/src/tools/ecode/plugins/aiassistant/acp/acpclient.cpp
+++ b/src/tools/ecode/plugins/aiassistant/acp/acpclient.cpp
@@ -152,6 +152,8 @@ void ACPClient::processResponse( const json& msg ) {
 
 	if ( handler ) {
 		handler( id, msg );
+	} else if ( msg.contains( "error" ) && onError ) {
+		onError( ResponseError( msg["error"] ) );
 	}
 }
 
@@ -194,54 +196,74 @@ void ACPClient::sendError( const json& id, int code, const std::string& message
 	}
 }
 
-void ACPClient::initialize( const InitializeRequest& req,
-							const std::function<void( const InitializeResponse& )>& cb ) {
+void ACPClient::initialize(
+	const InitializeRequest& req,
+	const std::function<void( const InitializeResponse&, const std::optional<ResponseError>& )>&
+		cb ) {
 	write( { { "method", "initialize" }, { "params", req.toJson() } },
 		   [this, cb]( const IdType&, const json& resp ) {
 			   if ( resp.contains( "result" ) ) {
 				   mReady = true;
 				   if ( cb )
-					   cb( InitializeResponse( resp["result"] ) );
+					   cb( InitializeResponse( resp["result"] ), std::nullopt );
+			   } else if ( resp.contains( "error" ) ) {
+				   if ( cb )
+					   cb( {}, ResponseError( resp["error"] ) );
 			   }
 		   } );
 }
 
-void ACPClient::newSession( const NewSessionRequest& req,
-							const std::function<void( const NewSessionResponse& )>& cb ) {
+void ACPClient::newSession(
+	const NewSessionRequest& req,
+	const std::function<void( const NewSessionResponse&, const std::optional<ResponseError>& )>&
+		cb ) {
 	write( { { "method", "session/new" }, { "params", req.toJson() } },
 		   [cb]( const IdType&, const json& resp ) {
 			   if ( resp.contains( "result" ) && cb ) {
-				   cb( NewSessionResponse( resp["result"] ) );
+				   cb( NewSessionResponse( resp["result"] ), std::nullopt );
+			   } else if ( resp.contains( "error" ) && cb ) {
+				   cb( {}, ResponseError( resp["error"] ) );
 			   }
 		   } );
 }
 
-void ACPClient::loadSession( const LoadSessionRequest& req,
-							 const std::function<void( const LoadSessionResponse& )>& cb ) {
+void ACPClient::loadSession(
+	const LoadSessionRequest& req,
+	const std::function<void( const LoadSessionResponse&, const std::optional<ResponseError>& )>&
+		cb ) {
 	write( { { "method", "session/load" }, { "params", req.toJson() } },
 		   [cb]( const IdType&, const json& resp ) {
 			   if ( resp.contains( "result" ) && cb ) {
-				   cb( LoadSessionResponse( resp["result"] ) );
+				   cb( LoadSessionResponse( resp["result"] ), std::nullopt );
+			   } else if ( resp.contains( "error" ) && cb ) {
+				   cb( {}, ResponseError( resp["error"] ) );
 			   }
 		   } );
 }
 
-void ACPClient::listSessions( const ListSessionsRequest& req,
-							  const std::function<void( const ListSessionsResponse& )>& cb ) {
+void ACPClient::listSessions(
+	const ListSessionsRequest& req,
+	const std::function<void( const ListSessionsResponse&, const std::optional<ResponseError>& )>&
+		cb ) {
 	write( { { "method", "session/list" }, { "params", req.toJson() } },
 		   [cb]( const IdType&, const json& resp ) {
 			   if ( resp.contains( "result" ) && cb ) {
-				   cb( ListSessionsResponse( resp["result"] ) );
+				   cb( ListSessionsResponse( resp["result"] ), std::nullopt );
+			   } else if ( resp.contains( "error" ) && cb ) {
+				   cb( {}, ResponseError( resp["error"] ) );
 			   }
 		   } );
 }
 
-void ACPClient::prompt( const PromptRequest& req,
-						const std::function<void( const PromptResponse& )>& cb ) {
+void ACPClient::prompt(
+	const PromptRequest& req,
+	const std::function<void( const PromptResponse&, const std::optional<ResponseError>& )>& cb ) {
 	write( { { "method", "session/prompt" }, { "params", req.toJson() } },
 		   [cb]( const IdType&, const json& resp ) {
 			   if ( resp.contains( "result" ) && cb ) {
-				   cb( PromptResponse( resp["result"] ) );
+				   cb( PromptResponse( resp["result"] ), std::nullopt );
+			   } else if ( resp.contains( "error" ) && cb ) {
+				   cb( {}, ResponseError( resp["error"] ) );
 			   }
 		   } );
 }
diff --git a/src/tools/ecode/plugins/aiassistant/acp/acpclient.hpp b/src/tools/ecode/plugins/aiassistant/acp/acpclient.hpp
index 98dab8993..57af63cf2 100644
--- a/src/tools/ecode/plugins/aiassistant/acp/acpclient.hpp
+++ b/src/tools/ecode/plugins/aiassistant/acp/acpclient.hpp
@@ -44,19 +44,26 @@ class ACPClient {
 	const Config& getConfig() const { return mConfig; }
 
 	void initialize( const InitializeRequest& req,
-					 const std::function<void( const InitializeResponse& )>& cb );
+					 const std::function<void( const InitializeResponse&,
+											   const std::optional<ResponseError>& )>& cb );
 	void newSession( const NewSessionRequest& req,
-					 const std::function<void( const NewSessionResponse& )>& cb );
+					 const std::function<void( const NewSessionResponse&,
+											   const std::optional<ResponseError>& )>& cb );
 	void loadSession( const LoadSessionRequest& req,
-					  const std::function<void( const LoadSessionResponse& )>& cb );
+					  const std::function<void( const LoadSessionResponse&,
+												const std::optional<ResponseError>& )>& cb );
 	void listSessions( const ListSessionsRequest& req,
-					   const std::function<void( const ListSessionsResponse& )>& cb );
-	void prompt( const PromptRequest& req, const std::function<void( const PromptResponse& )>& cb );
+					   const std::function<void( const ListSessionsResponse&,
+												 const std::optional<ResponseError>& )>& cb );
+	void prompt( const PromptRequest& req,
+				 const std::function<void( const PromptResponse&,
+										   const std::optional<ResponseError>& )>& cb );
 
 	// Notifications to agent
 	void cancel( const std::string& sessionId );
 
 	// Callbacks from agent
+	std::function<void( const ResponseError& )> onError;
 	std::function<void( const json& )> onSessionUpdate;
 	std::function<void( const ReadTextFileRequest&,
 						std::function<void( const ReadTextFileResponse& )> )>
diff --git a/src/tools/ecode/plugins/aiassistant/acp/acpprotocol.hpp b/src/tools/ecode/plugins/aiassistant/acp/acpprotocol.hpp
index 4b66363e0..e4ffb85da 100644
--- a/src/tools/ecode/plugins/aiassistant/acp/acpprotocol.hpp
+++ b/src/tools/ecode/plugins/aiassistant/acp/acpprotocol.hpp
@@ -105,6 +105,22 @@ struct ListSessionsResponse {
 	ListSessionsResponse( const json& body );
 };
 
+struct ResponseError {
+	int code{ 0 };
+	std::string message;
+	json data;
+
+	ResponseError() = default;
+	ResponseError( const json& body ) {
+		if ( body.contains( "code" ) )
+			code = body["code"].get<int>();
+		if ( body.contains( "message" ) )
+			message = body["message"].get<std::string>();
+		if ( body.contains( "data" ) )
+			data = body["data"];
+	}
+};
+
 struct PromptRequest {
 	std::string sessionId;
 	json prompt; // Array of ContentBlock
diff --git a/src/tools/ecode/plugins/aiassistant/acp/agentsession.cpp b/src/tools/ecode/plugins/aiassistant/acp/agentsession.cpp
index cd72a865e..629a35d62 100644
--- a/src/tools/ecode/plugins/aiassistant/acp/agentsession.cpp
+++ b/src/tools/ecode/plugins/aiassistant/acp/agentsession.cpp
@@ -21,15 +21,28 @@ bool AgentSession::start( const std::function<void( bool )>& onReady ) {
 		req.clientCapabilities.fsReadTextFile = true;
 		req.clientCapabilities.fsWriteTextFile = true;
 
-		mClient->initialize( req, [this, onReady]( const InitializeResponse& ) {
-			NewSessionRequest nreq;
-			nreq.cwd = mClient->isReady() ? mClient->getConfig().workingDirectory : "";
-			mClient->newSession( nreq, [this, onReady]( const NewSessionResponse& nres ) {
-				mSessionId = nres.sessionId;
-				if ( onReady )
-					onReady( true );
+		mClient->initialize(
+			req, [this, onReady]( const InitializeResponse&, const std::optional<ResponseError>& err ) {
+				if ( err ) {
+					if ( onReady )
+						onReady( false );
+					return;
+				}
+				NewSessionRequest nreq;
+				nreq.cwd = mClient->isReady() ? mClient->getConfig().workingDirectory : "";
+				mClient->newSession(
+					nreq, [this, onReady]( const NewSessionResponse& nres,
+										   const std::optional<ResponseError>& err ) {
+						if ( err ) {
+							if ( onReady )
+								onReady( false );
+							return;
+						}
+						mSessionId = nres.sessionId;
+						if ( onReady )
+							onReady( true );
+					} );
 			} );
-		} );
 		return true;
 	}
 	if ( onReady )
@@ -45,23 +58,35 @@ bool AgentSession::startLoaded( const std::string& sessionId,
 		req.clientCapabilities.fsReadTextFile = true;
 		req.clientCapabilities.fsWriteTextFile = true;
 
-		mClient->initialize( req, [this, sessionId, onReady]( const InitializeResponse& ires ) {
-			if ( ires.agentCapabilities.loadSession ) {
-				LoadSessionRequest lreq;
-				lreq.sessionId = sessionId;
-				lreq.cwd = mClient->isReady() ? mClient->getConfig().workingDirectory : "";
-				mClient->loadSession( lreq, [this, sessionId, onReady]( const LoadSessionResponse& ) {
-					mSessionId = sessionId;
+		mClient->initialize(
+			req, [this, sessionId, onReady]( const InitializeResponse& ires,
+											 const std::optional<ResponseError>& err ) {
+				if ( err ) {
 					if ( onReady )
-						onReady( true );
-				} );
-			} else {
-				// Agent doesn't support loading, fallback to new session?
-				// For now let's just fail or call onReady(false)
-				if ( onReady )
-					onReady( false );
-			}
-		} );
+						onReady( false );
+					return;
+				}
+				if ( ires.agentCapabilities.loadSession ) {
+					LoadSessionRequest lreq;
+					lreq.sessionId = sessionId;
+					lreq.cwd = mClient->isReady() ? mClient->getConfig().workingDirectory : "";
+					mClient->loadSession(
+						lreq, [this, sessionId, onReady]( const LoadSessionResponse&,
+														  const std::optional<ResponseError>& err ) {
+							if ( err ) {
+								if ( onReady )
+									onReady( false );
+								return;
+							}
+							mSessionId = sessionId;
+							if ( onReady )
+								onReady( true );
+						} );
+				} else {
+					if ( onReady )
+						onReady( false );
+				}
+			} );
 		return true;
 	}
 	if ( onReady )
@@ -69,16 +94,21 @@ bool AgentSession::startLoaded( const std::string& sessionId,
 	return false;
 }
 
-void AgentSession::listSessions( const std::function<void( const std::vector<SessionInfo>& )>& cb ) {
+void AgentSession::listSessions(
+	const std::function<void( const std::vector<SessionInfo>&, const std::optional<ResponseError>& )>&
+		cb ) {
 	if ( !mClient->isReady() ) {
-		if ( cb ) cb( {} );
+		if ( cb )
+			cb( {}, std::nullopt );
 		return;
 	}
 	ListSessionsRequest req;
 	req.cwd = mClient->getConfig().workingDirectory;
-	mClient->listSessions( req, [cb]( const ListSessionsResponse& res ) {
-		if ( cb ) cb( res.sessions );
-	} );
+	mClient->listSessions(
+		req, [cb]( const ListSessionsResponse& res, const std::optional<ResponseError>& err ) {
+			if ( cb )
+				cb( res.sessions, err );
+		} );
 }
 
 void AgentSession::stop() {
@@ -86,14 +116,16 @@ void AgentSession::stop() {
 		mClient->stop();
 }
 
-void AgentSession::prompt( const PromptRequest& req,
-						   const std::function<void( const PromptResponse& )>& cb ) {
+void AgentSession::prompt(
+	const PromptRequest& req,
+	const std::function<void( const PromptResponse&, const std::optional<ResponseError>& )>& cb ) {
 	mIsPrompting = true;
-	mClient->prompt( req, [this, cb](const PromptResponse& res) {
-		mIsPrompting = false;
-		if ( cb )
-			cb(res);
-	} );
+	mClient->prompt(
+		req, [this, cb]( const PromptResponse& res, const std::optional<ResponseError>& err ) {
+			mIsPrompting = false;
+			if ( cb )
+				cb( res, err );
+		} );
 }
 
 void AgentSession::cancel() {
@@ -108,6 +140,11 @@ void AgentSession::setTerminalData( const std::string& terminalId, UITerminal* u
 }
 
 void AgentSession::setupClient() {
+	mClient->onError = [this]( const ResponseError& err ) {
+		if ( onError )
+			onError( err );
+	};
+
 	mClient->onSessionUpdate = [this]( const json& msg ) {
 		if ( onSessionUpdate )
 			onSessionUpdate( msg );
diff --git a/src/tools/ecode/plugins/aiassistant/acp/agentsession.hpp b/src/tools/ecode/plugins/aiassistant/acp/agentsession.hpp
index 79aaee670..4093f1390 100644
--- a/src/tools/ecode/plugins/aiassistant/acp/agentsession.hpp
+++ b/src/tools/ecode/plugins/aiassistant/acp/agentsession.hpp
@@ -22,14 +22,19 @@ class AgentSession {
 
 	bool start( const std::function<void( bool )>& onReady );
 	bool startLoaded( const std::string& sessionId, const std::function<void( bool )>& onReady );
-	void listSessions( const std::function<void( const std::vector<SessionInfo>& )>& cb );
+	void listSessions(
+		const std::function<void( const std::vector<SessionInfo>&, const std::optional<ResponseError>& )>&
+			cb );
 	void stop();
 
-	void prompt( const PromptRequest& req, const std::function<void( const PromptResponse& )>& cb );
+	void prompt( const PromptRequest& req,
+				 const std::function<void( const PromptResponse&, const std::optional<ResponseError>& )>&
+					 cb );
 	void cancel();
 
 	bool isPrompting() const { return mIsPrompting; }
 
+	std::function<void( const ResponseError& )> onError;
 	std::function<void( const json& )> onSessionUpdate;
 	std::function<void( const RequestPermissionRequest&,
 						std::function<void( const RequestPermissionResponse& )> )>
diff --git a/src/tools/ecode/plugins/aiassistant/chatui.cpp b/src/tools/ecode/plugins/aiassistant/chatui.cpp
index 6f68404a9..3d71f6917 100644
--- a/src/tools/ecode/plugins/aiassistant/chatui.cpp
+++ b/src/tools/ecode/plugins/aiassistant/chatui.cpp
@@ -281,8 +281,11 @@ class AgentSessionHistoryModel : public Model {
 
 		switch ( index.column() ) {
 			case Columns::Title: {
-				return Variant( session.title.empty() ? "Untitled Session"
-													  : session.title.c_str() );
+				return Variant( session.title.empty()
+									? ( mUISceneNode ? mUISceneNode->i18n( "untitled_session",
+																		   "Untitled Session" )
+													 : "Untitled Session" )
+									: session.title.c_str() );
 			}
 			case Columns::UpdatedAt: {
 				return Variant( session.updatedAt.c_str() );
@@ -532,9 +535,10 @@ static const char* DEFAULT_CHAT_GLOBE = R"xml(
 
 static const char* DEFAULT_PERMISSION_GLOBE = R"xml(
 <vbox class="llm_conversation tool_permission" lw="mp" lh="wc" margin-bottom="8dp">
-	<hbox class="llm_conversation_opt" lw="mp" lh="wc" background-color="var(--primary)" padding="4dp">
-		<TextView text="Tool Call Permission Request" font-style="bold" margin-left="4dp" />
-	</hbox>
+    <hbox class="llm_conversation_opt" lw="mp" lh="wc" background-color="var(--primary)" padding="4dp">
+            <TextView text="@string(tool_call_permission_request, Tool Call Permission Request)" font-style="bold" margin-left="4dp" />
+    </hbox>
+
 	<vbox class="data_ui" lw="mp" lh="wc" padding="8dp" background-color="var(--tab-back)">
 		<TextView class="permission_desc" lw="mp" lh="wc" word-wrap="true" />
 		<hbox class="permission_options" lw="mp" lh="wc" margin-top="8dp" />
@@ -561,6 +565,7 @@ LLMChatUI::LLMChatUI( PluginManager* manager ) :
 	mChatAgentMode = find<UISelectButton>( "llm_agent_mode" );
 	mChatAgentMode->on( Event::OnValueChange, [this]( auto ) {
 		mIsAgentMode = mChatAgentMode->isSelected();
+		updateTabTitle();
 		updateAgentModeUI();
 	} );
 
@@ -1232,9 +1237,34 @@ void LLMChatUI::showChatHistory() {
 	UISceneNode* uiSceneNode = getUISceneNode();
 
 	if ( mIsAgentMode ) {
+		auto listSessionsCb = [winId, uiSceneNode, tv, loader, input](
+								  const std::vector<acp::SessionInfo>& sessions,
+								  const std::optional<acp::ResponseError>& err ) {
+			uiSceneNode->runOnMainThread( [winId, uiSceneNode, tv, loader, input, sessions, err] {
+				auto win = uiSceneNode->find( winId );
+				if ( win == nullptr )
+					return;
+				if ( err ) {
+					loader->setVisible( false );
+					NotificationCenter::instance()->addNotification(
+						uiSceneNode->i18n( "ai_assistant_agent_error", "Agent Error: " ) +
+						err->message );
+					win->asType<UIWindow>()->closeWindow();
+					return;
+				}
+				auto model = std::make_shared<AgentSessionHistoryModel>( sessions, uiSceneNode );
+				loader->setVisible( false );
+				input->setVisible( true );
+				tv->setVisible( true );
+				tv->setModel( model );
+				input->setFocus();
+			} );
+		};
+
 		if ( !mAgentSession ) {
 			setupAgentSession();
-			mAgentSession->start( [this, winId, uiSceneNode, tv, loader, input]( bool ready ) {
+
+			mAgentSession->start( [this, winId, uiSceneNode, loader, listSessionsCb]( bool ready ) {
 				if ( !ready ) {
 					uiSceneNode->runOnMainThread( [loader, winId, uiSceneNode] {
 						if ( uiSceneNode->find( winId ) == nullptr )
@@ -1243,37 +1273,10 @@ void LLMChatUI::showChatHistory() {
 					} );
 					return;
 				}
-				mAgentSession->listSessions( [winId, uiSceneNode, tv, loader, input](
-												 const std::vector<acp::SessionInfo>& sessions ) {
-					uiSceneNode->runOnMainThread(
-						[sessions, winId, uiSceneNode, tv, loader, input] {
-							if ( uiSceneNode->find( winId ) == nullptr )
-								return;
-							auto model =
-								std::make_shared<AgentSessionHistoryModel>( sessions, uiSceneNode );
-							loader->setVisible( false );
-							input->setVisible( true );
-							tv->setVisible( true );
-							tv->setModel( model );
-							input->setFocus();
-						} );
-				} );
+				mAgentSession->listSessions( listSessionsCb );
 			} );
 		} else {
-			mAgentSession->listSessions( [winId, uiSceneNode, tv, loader,
-										  input]( const std::vector<acp::SessionInfo>& sessions ) {
-				uiSceneNode->runOnMainThread( [sessions, winId, uiSceneNode, tv, loader, input] {
-					if ( uiSceneNode->find( winId ) == nullptr )
-						return;
-					auto model =
-						std::make_shared<AgentSessionHistoryModel>( sessions, uiSceneNode );
-					loader->setVisible( false );
-					input->setVisible( true );
-					tv->setVisible( true );
-					tv->setModel( model );
-					input->setFocus();
-				} );
-			} );
+			mAgentSession->listSessions( listSessionsCb );
 		}
 	} else {
 		getUISceneNode()->getThreadPool()->run(
@@ -1596,10 +1599,11 @@ void LLMChatUI::setupAgentSession() {
 				writeToLastChat( chunk );
 			}
 		} else if ( sessionUpdate == "tool_call" ) {
-			std::string toolStr = "\n> Tool Call: " + msg.value( "title", "" ) + "\n";
+			std::string toolStr = "\n> " + i18n( "tool_call", "Tool Call: " ) +
+								  msg.value( "title", "" ) + "\n";
 			writeToLastChat( toolStr );
 		} else if ( sessionUpdate == "plan" ) {
-			std::string planStr = "\n> Plan Updated:\n";
+			std::string planStr = "\n> " + i18n( "plan_updated", "Plan Updated:" ) + "\n";
 			if ( msg.contains( "plan" ) && msg["plan"].contains( "steps" ) &&
 				 msg["plan"]["steps"].is_array() ) {
 				for ( const auto& step : msg["plan"]["steps"] ) {
@@ -1623,7 +1627,13 @@ void LLMChatUI::setupAgentSession() {
 		runOnMainThread( [this, req, cb]() { addPermissionUI( req, cb ); } );
 	};
 
+	mAgentSession->onError = [this]( const acp::ResponseError& err ) {
+		NotificationCenter::instance()->addNotification(
+			i18n( "ai_assistant_agent_error", "Agent Error: " ) + err.message );
+	};
+
 	mAgentSession->onTerminalCreated = [this]( const acp::CreateTerminalRequest& req,
+
 											   const std::string& termId ) {
 		runOnMainThread( [this, req, termId] {
 			find( "chat_presentation" )->setVisible( false );
@@ -1755,7 +1765,22 @@ void LLMChatUI::sendAgentPrompt() {
 		req.prompt = { { { "type", "text" }, { "text", "" } } };
 	}
 
-	mAgentSession->prompt( req, [this]( const acp::PromptResponse& res ) {
+	mAgentSession->prompt( req, [this]( const acp::PromptResponse& res,
+										const std::optional<acp::ResponseError>& err ) {
+		if ( err ) {
+			runOnMainThread( [this] {
+				mChatStop->setVisible( false )->setEnabled( false );
+				mChatRun->setVisible( true )->setEnabled( true );
+				toggleEnableChats( true );
+				auto lastChat = getLastConversation();
+				if ( lastChat ) {
+					auto* thinking = lastChat->findByClass<UIImage>( "thinking" );
+					if ( thinking )
+						thinking->setVisible( false );
+				}
+			} );
+			return;
+		}
 		runOnMainThread( [this, res]() {
 			auto chat = getLastConversation();
 			if ( chat ) {
@@ -2241,14 +2266,15 @@ void LLMChatUI::addPermissionUI( const acp::RequestPermissionRequest& req,
 		mChatsList->getUISceneNode()->loadLayoutFromString( DEFAULT_PERMISSION_GLOBE, mChatsList );
 
 	UITextView* desc = chat->findByClass<UITextView>( "permission_desc" );
-	std::string descStr = "The agent wants to execute a tool call:\n";
-	descStr += "Title: " + req.toolCall.title + "\n";
-	descStr += "Kind: " + req.toolCall.kind + "\n";
+	std::string descStr =
+		i18n( "agent_wants_to_execute_tool_call", "The agent wants to execute a tool call:" ) +
+		"\n";
+	descStr += i18n( "title", "Title" ) + ": " + req.toolCall.title + "\n";
+	descStr += i18n( "kind", "Kind" ) + ": " + req.toolCall.kind + "\n";
 	if ( !req.toolCall.rawInput.is_null() ) {
-		descStr += "Input:\n" + req.toolCall.rawInput.dump( 2 ) + "\n";
+		descStr += i18n( "input", "Input" ) + ":\n" + req.toolCall.rawInput.dump( 2 ) + "\n";
 	}
 	desc->setText( descStr );
-
 	UIWidget* optionsBox = chat->findByClass( "permission_options" );
 
 	bool isFirst = true;