diff --git a/internal/app/app.go b/internal/app/app.go
index f044dd6f..f1671ffa 100644
--- a/internal/app/app.go
+++ b/internal/app/app.go
@@ -675,6 +675,7 @@ func setupRoutes(
 		protected.DELETE("/groups/:id", groupHandler.DeleteGroup)
 		protected.PUT("/groups/:id/pinned", groupHandler.UpdateGroupPinned)
 		protected.GET("/groups/:id/conversations", groupHandler.GetGroupConversations)
+		protected.GET("/groups/mappings", groupHandler.GetAllMappings)
 		protected.POST("/groups/conversations", groupHandler.AddConversationToGroup)
 		protected.DELETE("/groups/:id/conversations/:conversationId", groupHandler.RemoveConversationFromGroup)
 		protected.PUT("/groups/:id/conversations/:conversationId/pinned", groupHandler.UpdateConversationPinnedInGroup)
@@ -682,6 +683,7 @@ func setupRoutes(
 		// 监控
 		protected.GET("/monitor", monitorHandler.Monitor)
 		protected.GET("/monitor/execution/:id", monitorHandler.GetExecution)
+		protected.POST("/monitor/executions/names", monitorHandler.BatchGetToolNames)
 		protected.DELETE("/monitor/execution/:id", monitorHandler.DeleteExecution)
 		protected.DELETE("/monitor/executions", monitorHandler.DeleteExecutions)
 		protected.GET("/monitor/stats", monitorHandler.GetStats)
diff --git a/internal/database/conversation.go b/internal/database/conversation.go
index db180a94..ca2b1f5a 100644
--- a/internal/database/conversation.go
+++ b/internal/database/conversation.go
@@ -310,15 +310,14 @@ func (db *DB) ListConversations(limit, offset int, search string) ([]*Conversati
 	var err error
 	
 	if search != "" {
-		// 使用LIKE进行模糊搜索，搜索标题和消息内容
+		// 使用 EXISTS 子查询代替 LEFT JOIN + DISTINCT，避免大表笛卡尔积
 		searchPattern := "%" + search + "%"
-		// 使用DISTINCT避免重复，因为一个对话可能有多条消息匹配
 		rows, err = db.Query(
-			`SELECT DISTINCT c.id, c.title, COALESCE(c.pinned, 0), c.created_at, c.updated_at 
+			`SELECT c.id, c.title, COALESCE(c.pinned, 0), c.created_at, c.updated_at
 			 FROM conversations c
-			 LEFT JOIN messages m ON c.id = m.conversation_id
-			 WHERE c.title LIKE ? OR m.content LIKE ?
-			 ORDER BY c.updated_at DESC 
+			 WHERE c.title LIKE ?
+			    OR EXISTS (SELECT 1 FROM messages m WHERE m.conversation_id = c.id AND m.content LIKE ?)
+			 ORDER BY c.updated_at DESC
 			 LIMIT ? OFFSET ?`,
 			searchPattern, searchPattern, limit, offset,
 		)
diff --git a/internal/database/group.go b/internal/database/group.go
index 35e249f6..a3d32106 100644
--- a/internal/database/group.go
+++ b/internal/database/group.go
@@ -403,6 +403,35 @@ func (db *DB) UpdateGroupPinned(id string, pinned bool) error {
 	return nil
 }
 
+// GroupMapping 分组映射关系
+type GroupMapping struct {
+	ConversationID string `json:"conversationId"`
+	GroupID        string `json:"groupId"`
+}
+
+// GetAllGroupMappings 批量获取所有分组映射（消除 N+1 查询）
+func (db *DB) GetAllGroupMappings() ([]GroupMapping, error) {
+	rows, err := db.Query("SELECT conversation_id, group_id FROM conversation_group_mappings")
+	if err != nil {
+		return nil, fmt.Errorf("查询分组映射失败: %w", err)
+	}
+	defer rows.Close()
+
+	var mappings []GroupMapping
+	for rows.Next() {
+		var m GroupMapping
+		if err := rows.Scan(&m.ConversationID, &m.GroupID); err != nil {
+			return nil, fmt.Errorf("扫描分组映射失败: %w", err)
+		}
+		mappings = append(mappings, m)
+	}
+
+	if mappings == nil {
+		mappings = []GroupMapping{}
+	}
+	return mappings, nil
+}
+
 // UpdateConversationPinnedInGroup 更新对话在分组中的置顶状态
 func (db *DB) UpdateConversationPinnedInGroup(conversationID, groupID string, pinned bool) error {
 	pinnedValue := 0
diff --git a/internal/handler/group.go b/internal/handler/group.go
index d3bfc9a8..495e7695 100644
--- a/internal/handler/group.go
+++ b/internal/handler/group.go
@@ -234,6 +234,18 @@ func (h *GroupHandler) GetGroupConversations(c *gin.Context) {
 	c.JSON(http.StatusOK, groupConvs)
 }
 
+// GetAllMappings 批量获取所有分组映射（消除前端 N+1 请求）
+func (h *GroupHandler) GetAllMappings(c *gin.Context) {
+	mappings, err := h.db.GetAllGroupMappings()
+	if err != nil {
+		h.logger.Error("获取分组映射失败", zap.Error(err))
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, mappings)
+}
+
 // UpdateConversationPinnedRequest 更新对话置顶状态请求
 type UpdateConversationPinnedRequest struct {
 	Pinned bool `json:"pinned"`
diff --git a/internal/handler/monitor.go b/internal/handler/monitor.go
index e2ebc456..c337c374 100644
--- a/internal/handler/monitor.go
+++ b/internal/handler/monitor.go
@@ -246,6 +246,41 @@ func (h *MonitorHandler) GetExecution(c *gin.Context) {
 	c.JSON(http.StatusNotFound, gin.H{"error": "执行记录未找到"})
 }
 
+// BatchGetToolNames 批量获取工具执行的工具名称（消除前端 N+1 请求）
+func (h *MonitorHandler) BatchGetToolNames(c *gin.Context) {
+	var req struct {
+		IDs []string `json:"ids"`
+	}
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	result := make(map[string]string, len(req.IDs))
+	for _, id := range req.IDs {
+		// 先从内部MCP服务器查找
+		if exec, exists := h.mcpServer.GetExecution(id); exists {
+			result[id] = exec.ToolName
+			continue
+		}
+		// 再从外部MCP管理器查找
+		if h.externalMCPMgr != nil {
+			if exec, exists := h.externalMCPMgr.GetExecution(id); exists {
+				result[id] = exec.ToolName
+				continue
+			}
+		}
+		// 最后从数据库查找
+		if h.db != nil {
+			if exec, err := h.db.GetToolExecution(id); err == nil && exec != nil {
+				result[id] = exec.ToolName
+			}
+		}
+	}
+
+	c.JSON(http.StatusOK, result)
+}
+
 // GetStats 获取统计信息
 func (h *MonitorHandler) GetStats(c *gin.Context) {
 	stats := h.loadStats()
diff --git a/internal/multiagent/runner.go b/internal/multiagent/runner.go
index a04590c5..cda89530 100644
--- a/internal/multiagent/runner.go
+++ b/internal/multiagent/runner.go
@@ -233,6 +233,9 @@ func RunDeepAgent(
 				ToolsNodeConfig: compose.ToolsNodeConfig{
 					Tools:               subTools,
 					UnknownToolsHandler: einomcp.UnknownToolReminderHandler(),
+					ToolCallMiddlewares: []compose.ToolMiddleware{
+						{Invokable: softRecoveryToolCallMiddleware()},
+					},
 				},
 				EmitInternalEvents: true,
 			},
@@ -288,6 +291,9 @@ func RunDeepAgent(
 			ToolsNodeConfig: compose.ToolsNodeConfig{
 				Tools:               mainTools,
 				UnknownToolsHandler: einomcp.UnknownToolReminderHandler(),
+				ToolCallMiddlewares: []compose.ToolMiddleware{
+					{Invokable: softRecoveryToolCallMiddleware()},
+				},
 			},
 			EmitInternalEvents: true,
 		},
diff --git a/internal/multiagent/tool_args_json_retry.go b/internal/multiagent/tool_args_json_retry.go
index 9f97a0f0..d6d79971 100644
--- a/internal/multiagent/tool_args_json_retry.go
+++ b/internal/multiagent/tool_args_json_retry.go
@@ -10,7 +10,7 @@ import (
 // maxToolCallRecoveryAttempts 含首次运行：首次 + 自动重试次数。
 // 例如为 3 表示最多共 3 次完整 DeepAgent 运行（2 次失败后各追加一条纠错提示）。
 // 该常量同时用于 JSON 参数错误和工具执行错误（如子代理名称不存在）的恢复重试。
-const maxToolCallRecoveryAttempts = 3
+const maxToolCallRecoveryAttempts = 5
 
 // toolCallArgumentsJSONRetryHint 追加在用户消息后，提示模型输出合法 JSON 工具参数（部分云厂商会在流式阶段校验 arguments）。
 func toolCallArgumentsJSONRetryHint() *schema.Message {
diff --git a/internal/multiagent/tool_error_middleware.go b/internal/multiagent/tool_error_middleware.go
new file mode 100644
index 00000000..10158fc2
--- /dev/null
+++ b/internal/multiagent/tool_error_middleware.go
@@ -0,0 +1,131 @@
+package multiagent
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"strings"
+
+	"github.com/cloudwego/eino/compose"
+)
+
+// softRecoveryToolCallMiddleware returns an InvokableToolMiddleware that catches
+// specific recoverable errors from tool execution (JSON parse errors, tool-not-found,
+// etc.) and converts them into soft errors: nil error + descriptive error content
+// returned to the LLM. This allows the model to self-correct within the same
+// iteration rather than crashing the entire graph and requiring a full replay.
+//
+// Without this middleware, a JSON parse failure in any tool's InvokableRun propagates
+// as a hard error through the Eino ToolsNode → [NodeRunError] → ev.Err, which
+// either triggers the full-replay retry loop (expensive) or terminates the run
+// entirely once retries are exhausted. With it, the LLM simply sees an error message
+// in the tool result and can adjust its next tool call accordingly.
+func softRecoveryToolCallMiddleware() compose.InvokableToolMiddleware {
+	return func(next compose.InvokableToolEndpoint) compose.InvokableToolEndpoint {
+		return func(ctx context.Context, input *compose.ToolInput) (*compose.ToolOutput, error) {
+			output, err := next(ctx, input)
+			if err == nil {
+				return output, nil
+			}
+			if !isSoftRecoverableToolError(err) {
+				return output, err
+			}
+			// Convert the hard error into a soft error: the LLM will see this
+			// message as the tool's output and can self-correct.
+			msg := buildSoftRecoveryMessage(input.Name, input.Arguments, err)
+			return &compose.ToolOutput{Result: msg}, nil
+		}
+	}
+}
+
+// isSoftRecoverableToolError determines whether a tool execution error should be
+// silently converted to a tool-result message rather than crashing the graph.
+func isSoftRecoverableToolError(err error) bool {
+	if err == nil {
+		return false
+	}
+	s := strings.ToLower(err.Error())
+
+	// JSON unmarshal/parse failures — the model generated truncated or malformed arguments.
+	if isJSONRelatedError(s) {
+		return true
+	}
+
+	// Sub-agent type not found (from deep/task_tool.go)
+	if strings.Contains(s, "subagent type") && strings.Contains(s, "not found") {
+		return true
+	}
+
+	// Tool not found in ToolsNode indexes
+	if strings.Contains(s, "tool") && strings.Contains(s, "not found") {
+		return true
+	}
+
+	return false
+}
+
+// isJSONRelatedError checks whether an error string indicates a JSON parsing problem.
+func isJSONRelatedError(lower string) bool {
+	if !strings.Contains(lower, "json") {
+		return false
+	}
+	jsonIndicators := []string{
+		"unexpected end of json",
+		"unmarshal",
+		"invalid character",
+		"cannot unmarshal",
+		"invalid tool arguments",
+		"failed to unmarshal",
+		"must be in json format",
+		"unexpected eof",
+	}
+	for _, ind := range jsonIndicators {
+		if strings.Contains(lower, ind) {
+			return true
+		}
+	}
+	return false
+}
+
+// buildSoftRecoveryMessage creates a bilingual error message that the LLM can act on.
+func buildSoftRecoveryMessage(toolName, arguments string, err error) string {
+	// Truncate arguments preview to avoid flooding the context.
+	argPreview := arguments
+	if len(argPreview) > 300 {
+		argPreview = argPreview[:300] + "... (truncated)"
+	}
+
+	// Try to determine if it's specifically a JSON parse error for a friendlier message.
+	errStr := err.Error()
+	var jsonErr *json.SyntaxError
+	isJSONErr := strings.Contains(strings.ToLower(errStr), "json") ||
+		strings.Contains(strings.ToLower(errStr), "unmarshal")
+	_ = jsonErr // suppress unused
+
+	if isJSONErr {
+		return fmt.Sprintf(
+			"[Tool Error] The arguments for tool '%s' are not valid JSON and could not be parsed.\n"+
+				"Error: %s\n"+
+				"Arguments received: %s\n\n"+
+				"Please fix the JSON (ensure double-quoted keys, matched braces/brackets, no trailing commas, "+
+				"no truncation) and call the tool again.\n\n"+
+				"[工具错误] 工具 '%s' 的参数不是合法 JSON，无法解析。\n"+
+				"错误：%s\n"+
+				"收到的参数：%s\n\n"+
+				"请修正 JSON（确保双引号键名、括号配对、无尾部逗号、无截断），然后重新调用工具。",
+			toolName, errStr, argPreview,
+			toolName, errStr, argPreview,
+		)
+	}
+
+	return fmt.Sprintf(
+		"[Tool Error] Tool '%s' execution failed: %s\n"+
+			"Arguments: %s\n\n"+
+			"Please review the available tools and their expected arguments, then retry.\n\n"+
+			"[工具错误] 工具 '%s' 执行失败：%s\n"+
+			"参数：%s\n\n"+
+			"请检查可用工具及其参数要求，然后重试。",
+		toolName, errStr, argPreview,
+		toolName, errStr, argPreview,
+	)
+}
diff --git a/internal/multiagent/tool_error_middleware_test.go b/internal/multiagent/tool_error_middleware_test.go
new file mode 100644
index 00000000..d87e417b
--- /dev/null
+++ b/internal/multiagent/tool_error_middleware_test.go
@@ -0,0 +1,166 @@
+package multiagent
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"testing"
+
+	"github.com/cloudwego/eino/compose"
+)
+
+func TestIsSoftRecoverableToolError(t *testing.T) {
+	tests := []struct {
+		name     string
+		err      error
+		expected bool
+	}{
+		{
+			name:     "nil error",
+			err:      nil,
+			expected: false,
+		},
+		{
+			name:     "unexpected end of JSON input",
+			err:      errors.New("unexpected end of JSON input"),
+			expected: true,
+		},
+		{
+			name:     "failed to unmarshal task tool input json",
+			err:      errors.New("failed to unmarshal task tool input json: unexpected end of JSON input"),
+			expected: true,
+		},
+		{
+			name:     "invalid tool arguments JSON",
+			err:      errors.New("invalid tool arguments JSON: unexpected end of JSON input"),
+			expected: true,
+		},
+		{
+			name:     "json invalid character",
+			err:      errors.New(`invalid character '}' looking for beginning of value in JSON`),
+			expected: true,
+		},
+		{
+			name:     "subagent type not found",
+			err:      errors.New("subagent type recon_agent not found"),
+			expected: true,
+		},
+		{
+			name:     "tool not found",
+			err:      errors.New("tool nmap_scan not found in toolsNode indexes"),
+			expected: true,
+		},
+		{
+			name:     "unrelated network error",
+			err:      errors.New("connection refused"),
+			expected: false,
+		},
+		{
+			name:     "context cancelled",
+			err:      context.Canceled,
+			expected: false,
+		},
+		{
+			name: "real json unmarshal error",
+			err: func() error {
+				var v map[string]interface{}
+				return json.Unmarshal([]byte(`{"key": `), &v)
+			}(),
+			expected: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := isSoftRecoverableToolError(tt.err)
+			if got != tt.expected {
+				t.Errorf("isSoftRecoverableToolError(%v) = %v, want %v", tt.err, got, tt.expected)
+			}
+		})
+	}
+}
+
+func TestSoftRecoveryToolCallMiddleware_PassesThrough(t *testing.T) {
+	mw := softRecoveryToolCallMiddleware()
+	called := false
+	next := func(ctx context.Context, input *compose.ToolInput) (*compose.ToolOutput, error) {
+		called = true
+		return &compose.ToolOutput{Result: "success"}, nil
+	}
+	wrapped := mw(next)
+	out, err := wrapped(context.Background(), &compose.ToolInput{
+		Name:      "test_tool",
+		Arguments: `{"key": "value"}`,
+	})
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if !called {
+		t.Fatal("next endpoint was not called")
+	}
+	if out.Result != "success" {
+		t.Fatalf("expected 'success', got %q", out.Result)
+	}
+}
+
+func TestSoftRecoveryToolCallMiddleware_ConvertsJSONError(t *testing.T) {
+	mw := softRecoveryToolCallMiddleware()
+	next := func(ctx context.Context, input *compose.ToolInput) (*compose.ToolOutput, error) {
+		return nil, errors.New("failed to unmarshal task tool input json: unexpected end of JSON input")
+	}
+	wrapped := mw(next)
+	out, err := wrapped(context.Background(), &compose.ToolInput{
+		Name:      "task",
+		Arguments: `{"subagent_type": "recon`,
+	})
+	if err != nil {
+		t.Fatalf("expected nil error (soft recovery), got: %v", err)
+	}
+	if out == nil || out.Result == "" {
+		t.Fatal("expected non-empty recovery message")
+	}
+	if !containsAll(out.Result, "[Tool Error]", "task", "JSON") {
+		t.Fatalf("recovery message missing expected content: %s", out.Result)
+	}
+}
+
+func TestSoftRecoveryToolCallMiddleware_PropagatesNonRecoverable(t *testing.T) {
+	mw := softRecoveryToolCallMiddleware()
+	origErr := errors.New("connection timeout to remote server")
+	next := func(ctx context.Context, input *compose.ToolInput) (*compose.ToolOutput, error) {
+		return nil, origErr
+	}
+	wrapped := mw(next)
+	_, err := wrapped(context.Background(), &compose.ToolInput{
+		Name:      "test_tool",
+		Arguments: `{}`,
+	})
+	if err == nil {
+		t.Fatal("expected error to propagate for non-recoverable errors")
+	}
+	if err != origErr {
+		t.Fatalf("expected original error, got: %v", err)
+	}
+}
+
+func containsAll(s string, subs ...string) bool {
+	for _, sub := range subs {
+		if !contains(s, sub) {
+			return false
+		}
+	}
+	return true
+}
+
+func contains(s, sub string) bool {
+	return len(s) >= len(sub) && searchString(s, sub)
+}
+
+func searchString(s, sub string) bool {
+	for i := 0; i <= len(s)-len(sub); i++ {
+		if s[i:i+len(sub)] == sub {
+			return true
+		}
+	}
+	return false
+}