feat: 增强聊天引擎，处理工具调用记录并优化最终回复内容

app/composables/useAgentChat.ts

@@ -423,6 +423,14 @@ export function useAgentChat(options: UseAgentChatOptions) {
           type: "text",
           text: "（模型仅返回了思考过程，未生成正式回复。请尝试更换模型或调整问题后重试。）",
         });
+      } else if (!hasText && hasToolCall) {
+        finalMsg.parts?.push({
+          id: generateId(),
+          type: "text",
+          text: isStopped.value
+            ? "（对话已停止，以上是已完成的工具调用记录。）"
+            : "（已达到工具调用次数上限，模型未能生成最终回答。以上是工具调用的执行记录。）",
+        });
       }
     }
   }
@@ -533,6 +541,7 @@ export function useAgentChat(options: UseAgentChatOptions) {
         const msg = messages.value[assistantIdx];
         if (msg) {
           cleanupInProgressToolCalls(msg);
+          validateAssistantContent(assistantIdx);
         }
       } else {
         errorMessage.value = err.message || "请求失败";
@@ -645,6 +654,7 @@ export function useAgentChat(options: UseAgentChatOptions) {
         const msg = messages.value[messages.value.indexOf(assistantMsg)];
         if (msg) {
           cleanupInProgressToolCalls(msg);
+          validateAssistantContent(messages.value.indexOf(assistantMsg), true);
         }
       } else {
         errorMessage.value = err.message || "请求失败";

server/service/agent/chat-engine.ts

@@ -504,6 +504,7 @@ export async function executeChat(params: ChatEngineParams): Promise<ChatEngineR
         );
 
         const parts: Array<Record<string, unknown>> = [];
+        let hasTextPart = false;
         for (const step of steps) {
           const toolResultMap = new Map(step.toolResults.map((tr) => [tr.toolCallId, tr.output]));
           const contentArr = step.content as Array<Record<string, unknown>>;
@@ -518,6 +519,7 @@ export async function executeChat(params: ChatEngineParams): Promise<ChatEngineR
               parts.push({ id: `p_${parts.length}`, type: "reasoning", text: (cp as any).text });
             } else if (cp.type === "text" && (cp as any).text) {
               parts.push({ id: `p_${parts.length}`, type: "text", text: (cp as any).text });
+              hasTextPart = true;
             } else if (cp.type === "tool-approval-request" && (cp as any).approvalId && (cp as any).toolCall) {
               const tc = (cp as any).toolCall;
               const toolResult = toolResultMap.get(tc.toolCallId);
@@ -560,6 +562,16 @@ export async function executeChat(params: ChatEngineParams): Promise<ChatEngineR
           }
         }
 
+        const hasToolCallPart = parts.some((p) => p.type === "tool-call");
+        const stepLimitReached = finishReason === "tool-calls" && !hasTextPart && hasToolCallPart;
+        let finalText = assistantText;
+        if (stepLimitReached) {
+          const noticeText = "（已达到工具调用次数上限，模型未能生成最终回答。以上是工具调用的执行记录。）";
+          parts.push({ id: `p_${parts.length}`, type: "text", text: noticeText });
+          finalText = (finalText || "") + noticeText;
+          logger.info("[%s] [CHAT-ENGINE] step limit reached, appended notice part", requestId);
+        }
+
         if (isApprovalContinue) {
           const lastAssistant = historyMessages.filter((m) => m.role === "assistant").pop();
           if (lastAssistant) {
@@ -590,7 +602,7 @@ export async function executeChat(params: ChatEngineParams): Promise<ChatEngineR
               newParts[i]!.id = `p_${idOffset + i}`;
             }
             const mergedParts = [...existingParts, ...newParts];
-            const mergedContent = (lastAssistant.content || "") + assistantText;
+            const mergedContent = (lastAssistant.content || "") + finalText;
             await updateMessageContent(lastAssistant.id, mergedContent);
             await updateMessageParts(lastAssistant.id, JSON.stringify(mergedParts));
           }
@@ -599,7 +611,7 @@ export async function executeChat(params: ChatEngineParams): Promise<ChatEngineR
           await saveMessage({
             sessionId,
             role: "assistant",
-            content: assistantText,
+            content: finalText,
             parts: parts.length > 0 ? JSON.stringify(parts) : null,
             modelId: resolvedModel.dbId,
             inputTokens: usage?.inputTokens ?? null,
@@ -641,11 +653,13 @@ export async function executeChat(params: ChatEngineParams): Promise<ChatEngineR
         logger.info("[%s] [CHAT-ENGINE] aborted: streamedTextLen=%d streamedToolCalls=%d", requestId, partialText.length, streamedToolCalls.length);
 
         const parts: Array<Record<string, unknown>> = [];
+        let hasTextPart = false;
         if (streamedReasoning.trim()) {
           parts.push({ id: `p_${parts.length}`, type: "reasoning", text: streamedReasoning });
         }
         if (partialText.trim()) {
           parts.push({ id: `p_${parts.length}`, type: "text", text: partialText });
+          hasTextPart = true;
         }
         for (const tc of streamedToolCalls) {
           parts.push({
@@ -659,6 +673,15 @@ export async function executeChat(params: ChatEngineParams): Promise<ChatEngineR
           });
         }
 
+        const hasToolCallPart = parts.some((p) => p.type === "tool-call");
+        let finalText = partialText;
+        if (!hasTextPart && hasToolCallPart) {
+          const noticeText = "（对话已停止，以上是已完成的工具调用记录。）";
+          parts.push({ id: `p_${parts.length}`, type: "text", text: noticeText });
+          finalText = (finalText || "") + noticeText;
+          logger.info("[%s] [CHAT-ENGINE] aborted with tool calls but no text, appended notice", requestId);
+        }
+
         if (isApprovalContinue) {
           const lastAssistant = historyMessages.filter((m) => m.role === "assistant").pop();
           if (lastAssistant) {
@@ -688,18 +711,18 @@ export async function executeChat(params: ChatEngineParams): Promise<ChatEngineR
               newParts[i]!.id = `p_${idOffset + i}`;
             }
             const mergedParts = [...existingParts, ...newParts];
-            const mergedContent = (lastAssistant.content || "") + partialText;
+            const mergedContent = (lastAssistant.content || "") + finalText;
             await updateMessageContent(lastAssistant.id, mergedContent);
             await updateMessageParts(lastAssistant.id, JSON.stringify(mergedParts));
           }
         } else {
-          const hasContent = partialText.trim().length > 0 || parts.length > 0;
+          const hasContent = finalText.trim().length > 0 || parts.length > 0;
           if (hasContent) {
             const assistantSortOrder = (await getMaxSortOrder(sessionId)) + 1;
             await saveMessage({
               sessionId,
               role: "assistant",
-              content: partialText,
+              content: finalText,
               parts: parts.length > 0 ? JSON.stringify(parts) : null,
               modelId: resolvedModel.dbId,
               sortOrder: assistantSortOrder,