@@ -155,6 +155,8 @@ type StreamRuntime = {
 	lastOffset: number
 	modelContent: string
 	hasStreamEvents: boolean
+	receivedStart: boolean
+	streamCompleted: boolean
 	streamFailed: boolean
 }
 
@@ -176,9 +178,7 @@ async function consumeSseStream(
 		switch (sseEvent.event) {
 			case 'start': {
 				const data = sseEvent.data as { message_uuid?: string }
-				if (data?.message_uuid) {
-					handlers.onStart?.(data.message_uuid)
-				}
+				handlers.onStart?.(data?.message_uuid ?? '')
 				break
 			}
 			case 'token': {
@@ -222,6 +222,8 @@ export function useChatModel(
 		lastOffset: 0,
 		modelContent: '',
 		hasStreamEvents: false,
+		receivedStart: false,
+		streamCompleted: false,
 		streamFailed: false,
 	})
 
@@ -242,6 +244,8 @@ export function useChatModel(
 			lastOffset: 0,
 			modelContent,
 			hasStreamEvents: false,
+			receivedStart: false,
+			streamCompleted: false,
 			streamFailed: false,
 		}
 	}, [])
@@ -268,7 +272,13 @@ export function useChatModel(
 
 			await consumeSseStream(response.body, {
 				onStart: (messageUuid) => {
+					runtime.receivedStart = true
 					runtime.hasStreamEvents = true
+
+					if (!messageUuid) {
+						return
+					}
+
 					inputMessageUuidRef.current = messageUuid
 
 					if (!runtime.modelContent) {
@@ -335,6 +345,8 @@ export function useChatModel(
 					})
 				},
 				onDone: (content) => {
+					runtime.streamCompleted = true
+
 					const inputUuid = inputMessageUuidRef.current
 					if (!inputUuid) {
 						return
@@ -342,7 +354,6 @@ export function useChatModel(
 
 					clearChatStreamSession(currentChat)
 					runtime.modelContent = content
-					runtime.hasStreamEvents = false
 
 					setMessages((prev) => {
 						if (!prev) {
@@ -367,7 +378,9 @@ export function useChatModel(
 			return {
 				shouldReconnect: runtime.streamFailed && (runtime.hasStreamEvents || hasActiveSession),
 				streamFailed: runtime.streamFailed,
-				missingStart: !runtime.hasStreamEvents && !options.isReconnect && !hasActiveSession,
+				missingStart: !runtime.receivedStart && !options.isReconnect && !runtime.streamCompleted,
+				receivedStart: runtime.receivedStart,
+				streamCompleted: runtime.streamCompleted,
 			}
 		},
 		[currentChat, modelType, persistStreamSession]
@@ -613,12 +626,18 @@ export function useChatModel(
 						if (error.detail) {
 							showMessage(error.detail)
 						} else {
+							console.error('[useChatModel] sendMessage: HTTP error without detail', {
+								chatUid: currentChat,
+								status,
+								result,
+							})
 							showMessage('Непредвиденная ошибка, попробуйте еще раз')
 						}
 					} else {
 						setMessages((prev) => [...(prev ?? []), ...(result as Message[])])
 					}
-				} catch {
+				} catch (error) {
+					console.error('[useChatModel] sendMessage: request failed', { chatUid: currentChat, error })
 					setMessages((prev) => {
 						const withoutPlaceholder = prev?.slice(0, -2) ?? []
 						return [...withoutPlaceholder, { ...userMessage, is_sent: false }]
@@ -688,12 +707,17 @@ export function useChatModel(
 				}
 
 				if (result.missingStart) {
+					console.error('[useChatModel] sendMessageStream: missing start event', {
+						chatUid: currentChat,
+						result,
+						inputMessageUuid: inputMessageUuidRef.current,
+					})
 					clearChatStreamSession(currentChat)
 					markOptimisticUserMessageFailed()
 					setMessages((prev) => removeStreamingModelMessage(prev))
 					showMessage('Непредвиденная ошибка, попробуйте еще раз')
 				}
-			} catch {
+			} catch (error) {
 				if (abortController.signal.aborted) {
 					return
 				}
@@ -709,6 +733,12 @@ export function useChatModel(
 
 				markOptimisticUserMessageFailed()
 				setMessages((prev) => removeStreamingModelMessage(prev))
+				console.error('[useChatModel] sendMessageStream: request failed', {
+					chatUid: currentChat,
+					error,
+					inputMessageUuid: inputMessageUuidRef.current,
+					streamRuntime: streamRuntimeRef.current,
+				})
 				showMessage('Непредвиденная ошибка, попробуйте еще раз')
 			} finally {
 				isSendingRef.current = false