diff --git a/pkg/friday/friday.go b/pkg/friday/friday.go
index 87951d3..bcade3b 100644
--- a/pkg/friday/friday.go
+++ b/pkg/friday/friday.go
@@ -62,10 +62,12 @@ type Statement struct {
 	context context.Context
 
 	// for chat
-	history  []map[string]string
-	question string
-	query    *models.DocQuery
-	info     string
+	summary        string              // summary of doc
+	history        []map[string]string // real chat history
+	question       string              // question for chat
+	query          *models.DocQuery    // search in doc or dir
+	historySummary string              // summary of chat history
+	info           string              // info of embedding
 
 	// for ingest or summary
 	file        *models.File // a whole file providing models.File
diff --git a/pkg/friday/question.go b/pkg/friday/question.go
index 34a467a..fdaebbe 100644
--- a/pkg/friday/question.go
+++ b/pkg/friday/question.go
@@ -17,15 +17,17 @@
 package friday
 
 import (
+	"bytes"
 	"errors"
 	"fmt"
+	"html/template"
 	"strings"
 
 	"github.com/basenana/friday/pkg/llm/prompts"
 	"github.com/basenana/friday/pkg/models"
 )
 
-const remainHistoryNum = 3 // must be odd
+const remainHistoryNum = 5 // must be odd
 
 func (f *Friday) History(history []map[string]string) *Friday {
 	f.statement.history = history
@@ -42,22 +44,40 @@ func (f *Friday) Question(q string) *Friday {
 	return f
 }
 
+func (f *Friday) OfSummary(summary string) *Friday {
+	f.statement.summary = summary
+	return f
+}
+
 func (f *Friday) GetRealHistory() []map[string]string {
 	return f.statement.history
 }
 
-func (f *Friday) Chat(res *ChatState) *Friday {
+func (f *Friday) preCheck(res *ChatState) error {
 	if len(f.statement.history) == 0 {
-		f.Error = errors.New("history can not be nil")
-		return f
+		return errors.New("history can not be nil")
 	}
 	if f.LLM == nil {
-		f.Error = errors.New("llm client of friday is not set")
+		return errors.New("llm client of friday is not set")
+	}
+	if res == nil {
+		return errors.New("result can not be nil")
+	}
+	return nil
+}
+
+func (f *Friday) Chat(res *ChatState) *Friday {
+	if f.Error = f.preCheck(res); f.Error != nil {
 		return f
 	}
 
+	var (
+		dialogues  = []map[string]string{}
+		systemInfo = ""
+	)
+
+	// search for docs
 	if f.statement.query != nil {
-		// search for docs
 		questions := ""
 		for _, d := range f.statement.history {
 			if d["role"] == f.LLM.GetUserModel() {
@@ -69,88 +89,29 @@ func (f *Friday) Chat(res *ChatState) *Friday {
 			return f
 		}
 	}
+
+	// If the number of dialogue rounds exceeds some rounds, should conclude it.
+	if len(f.statement.history) >= remainHistoryNum {
+		f.statement.historySummary = f.summaryHistory().statement.historySummary
+		if f.Error != nil {
+			return f
+		}
+	}
+
+	// if it already has system info, rewrite it
 	if (f.statement.history)[0]["role"] == "system" {
 		f.statement.history = f.statement.history[1:]
 	}
-	f.statement.history = append([]map[string]string{
-		{
-			"role":    f.LLM.GetSystemModel(),
-			"content": fmt.Sprintf("基于以下已知信息，简洁和专业的来回答用户的问题。答案请使用中文。 \n\n已知内容: %s\n", f.statement.info),
-		},
-		{
-			"role":    f.LLM.GetAssistantModel(),
-			"content": "",
-		},
-	}, f.statement.history...)
-
-	return f.chat(res)
-}
 
-func (f *Friday) chat(res *ChatState) *Friday {
-	if res == nil {
-		f.Error = errors.New("result can not be nil")
-		return f
-	}
-	var (
-		dialogues = []map[string]string{}
-	)
+	// regenerate system info
+	systemInfo = f.generateSystemInfo()
 
-	// If the number of dialogue rounds exceeds 2 rounds, should conclude it.
 	if len(f.statement.history) >= remainHistoryNum {
-		sumDialogue := make([]map[string]string, len(f.statement.history))
-		copy(sumDialogue, f.statement.history)
-		sumDialogue[len(sumDialogue)-1] = map[string]string{
-			"role":    f.LLM.GetSystemModel(),
-			"content": "简要总结一下对话内容，用作后续的上下文提示 prompt，控制在 200 字以内",
-		}
-		var (
-			sumBuf = make(chan map[string]string)
-			sum    = make(map[string]string)
-			errCh  = make(chan error)
-		)
-		go func() {
-			defer close(errCh)
-			_, err := f.LLM.Chat(f.statement.context, false, sumDialogue, sumBuf)
-			errCh <- err
-		}()
-		select {
-		case err := <-errCh:
-			if err != nil {
-				f.Error = err
-				return f
-			}
-		case sum = <-sumBuf:
-			// add context prompt for dialogue
-			if f.statement.query != nil {
-				// there has been ingest info, combine them.
-				dialogues = []map[string]string{
-					{
-						"role": f.LLM.GetSystemModel(),
-						"content": fmt.Sprintf(
-							"%s\n%s",
-							f.statement.history[0]["content"],
-							fmt.Sprintf("这是历史聊天总结作为前情提要：%s\n", sum["content"]),
-						),
-					},
-					{
-						"role":    f.LLM.GetAssistantModel(),
-						"content": "",
-					},
-				}
-			} else {
-				dialogues = []map[string]string{
-					{
-						"role":    f.LLM.GetSystemModel(),
-						"content": fmt.Sprintf("这是历史聊天总结作为前情提要：%s", sum["content"]),
-					},
-					{
-						"role":    f.LLM.GetAssistantModel(),
-						"content": "",
-					},
-				}
-			}
-			dialogues = append(dialogues, f.statement.history[len(f.statement.history)-remainHistoryNum:len(f.statement.history)]...)
+		dialogues = []map[string]string{
+			{"role": f.LLM.GetSystemModel(), "content": systemInfo},
+			{"role": f.LLM.GetAssistantModel(), "content": ""},
 		}
+		dialogues = append(dialogues, f.statement.history[len(f.statement.history)-remainHistoryNum:len(f.statement.history)]...)
 	} else {
 		dialogues = make([]map[string]string, len(f.statement.history))
 		copy(dialogues, f.statement.history)
@@ -158,10 +119,55 @@ func (f *Friday) chat(res *ChatState) *Friday {
 
 	// go for llm
 	f.statement.history = dialogues // return realHistory
-	_, err := f.LLM.Chat(f.statement.context, true, dialogues, res.Response)
-	if err != nil {
-		f.Error = err
-		return f
+	_, f.Error = f.LLM.Chat(f.statement.context, true, dialogues, res.Response)
+	return f
+}
+
+func (f *Friday) generateSystemInfo() string {
+	systemTemplate := "基于以下内容，简洁和专业的来回答用户的问题。答案请使用中文。\n"
+	if f.statement.summary != "" {
+		systemTemplate += "\n这是文章简介: {{ .Summary }}\n"
+	}
+	if f.statement.info != "" {
+		systemTemplate += "\n这是已知内容: {{ .Info }}\n"
+	}
+	if f.statement.historySummary != "" {
+		systemTemplate += "\n这是历史聊天总结作为前情提要: {{ .HistorySummary }}\n"
+	}
+
+	temp := template.Must(template.New("systemInfo").Parse(systemTemplate))
+	prompt := new(bytes.Buffer)
+	f.Error = temp.Execute(prompt, f.statement)
+	if f.Error != nil {
+		return ""
+	}
+	return prompt.String()
+}
+
+func (f *Friday) summaryHistory() *Friday {
+	sumDialogue := make([]map[string]string, len(f.statement.history))
+	copy(sumDialogue, f.statement.history)
+	sumDialogue[len(sumDialogue)-1] = map[string]string{
+		"role":    f.LLM.GetSystemModel(),
+		"content": "简要总结一下对话内容，用作后续的上下文提示 prompt，控制在 200 字以内",
+	}
+	var (
+		sumBuf = make(chan map[string]string)
+		sum    = make(map[string]string)
+		errCh  = make(chan error)
+	)
+	go func() {
+		defer close(errCh)
+		_, err := f.LLM.Chat(f.statement.context, false, sumDialogue, sumBuf)
+		errCh <- err
+	}()
+	select {
+	case err := <-errCh:
+		if err != nil {
+			f.Error = err
+		}
+	case sum = <-sumBuf:
+		f.statement.historySummary = sum["content"]
 	}
 	return f
 }
diff --git a/pkg/friday/question_test.go b/pkg/friday/question_test.go
index 5ed0811..a765b69 100644
--- a/pkg/friday/question_test.go
+++ b/pkg/friday/question_test.go
@@ -76,7 +76,6 @@ var _ = Describe("TestQuestion", func() {
 			)
 			go func() {
 				f = loFriday.WithContext(context.TODO()).SearchIn(&models.DocQuery{ParentId: 1}).History(history).Chat(&res)
-				close(res.Response)
 			}()
 			resp := <-res.Response
 			Expect(f.Error).Should(BeNil())
@@ -106,7 +105,6 @@ var _ = Describe("TestQuestion", func() {
 			)
 			go func() {
 				f = loFriday.WithContext(context.TODO()).SearchIn(&models.DocQuery{ParentId: 1}).History(history).Chat(&res)
-				close(res.Response)
 			}()
 			resp := <-res.Response
 			Expect(f.Error).Should(BeNil())
@@ -144,7 +142,6 @@ var _ = Describe("TestQuestion", func() {
 			)
 			go func() {
 				f = loFriday.WithContext(context.TODO()).SearchIn(&models.DocQuery{ParentId: 1}).History(history).Chat(&res)
-				close(res.Response)
 			}()
 			resp := <-res.Response
 
@@ -191,7 +188,6 @@ var _ = Describe("TestQuestion", func() {
 			)
 			go func() {
 				f = loFriday.WithContext(context.TODO()).SearchIn(&models.DocQuery{ParentId: 1}).History(history).Chat(&res)
-				close(res.Response)
 			}()
 			resp := <-res.Response
 			Expect(f.Error).Should(BeNil())