diff --git a/bigmodel/bigmodel.go b/bigmodel/bigmodel.go
index aec0f13..3613b83 100644
--- a/bigmodel/bigmodel.go
+++ b/bigmodel/bigmodel.go
@@ -22,7 +22,7 @@ package bigmodel
 // BigModel interface
 type BigModel interface {
 	// Chat Receive a query for large model calls and write the output results to the Result channel in real time
-	Chat(query string) chan Result
+	Chat(string) chan Result
 }
 
 type Result struct {
diff --git a/bigmodel/chatgpt.go b/bigmodel/chatgpt.go
index 0df0f27..3e95eee 100644
--- a/bigmodel/chatgpt.go
+++ b/bigmodel/chatgpt.go
@@ -75,7 +75,7 @@ type chunk struct {
 	} `json:"choices"`
 }
 
-func (gpt *ChatGPT) Chat(query string) chan Result {
+func (gpt *ChatGPT) Chat(prompt string) chan Result {
 	out := make(chan Result)
 
 	go func() {
@@ -86,7 +86,7 @@ func (gpt *ChatGPT) Chat(query string) chan Result {
 			"messages": []map[string]string{
 				{
 					"role":    "user",
-					"content": query,
+					"content": prompt,
 				},
 			},
 		})
@@ -104,7 +104,7 @@ func (gpt *ChatGPT) Chat(query string) chan Result {
 		// TODO: response status exception
 
 		// read response stream data
-		buf := make([]byte, 1024)
+		buf := make([]byte, 4096)
 		var chunks, tmp string
 		for {
 			n, err := resp.Body.Read(buf)
diff --git a/diagnostic/diagnostic.go b/diagnostic/diagnostic.go
index f0c34f6..771c288 100644
--- a/diagnostic/diagnostic.go
+++ b/diagnostic/diagnostic.go
@@ -21,13 +21,12 @@ package diagnostic
 
 import (
 	"fmt"
+	"github.com/ahaostudy/code-diagnostic/bigmodel"
 	"log"
 	"os"
 	"runtime"
 	"runtime/debug"
 	"strings"
-
-	"github.com/ahaostudy/code-diagnostic/bigmodel"
 )
 
 const (
@@ -69,38 +68,36 @@ func (diag *Diag) Diagnostic() {
 			pnc,
 			strings.ReplaceAll(stack, "\n", "\n\t"),
 		)
-
 		frames := getCallersFrames(defaultMaxStack)
-		funcList := GetFuncList(frames)
-		diag.Analyze(pnc, stack, funcList)
+		funs := GetFuncList(frames)
+		diag.analyze(pnc, stack, funs)
 	}
 }
 
-func getCallersFrames(max int) *runtime.Frames {
-	pc := make([]uintptr, max)
-	// remove the call stack of diagnostic package
-	n := runtime.Callers(4, pc)
-	pc = pc[:n]
-	return runtime.CallersFrames(pc)
+func (diag *Diag) BreakPoint(pnc string) {
+	stack := string(debug.Stack())
+	log.Printf("diagnostic detected:\n\n\t%v\n\n\t%v",
+		pnc,
+		strings.ReplaceAll(stack, "\n", "\n\t"),
+	)
+	frames := getCallersFrames(defaultMaxStack)
+	funs := GetFuncList(frames)
+	diag.analyze(pnc, stack, funs)
 }
 
-func (diag *Diag) Analyze(pnc, stack string, funs []*Function) {
-	funcListDescription := buildFuncListDescription(funs)
-
-	var query string
-	query += "The following error occurred in the current program: \n```\n" + pnc + "\n```\n\n"
-	query += "Here is its call stack: \n```\n" + stack + "```\n\n"
-	query += "The source code list is as follows:\n" + funcListDescription + "\n"
+func (diag *Diag) analyze(pnc, stack string, funs []*Function) {
+	var prompt string
+	prompt += "The following error occurred in the current program: \n```\n" + pnc + "\n```\n\n"
+	prompt += "Here is its call stack: \n```\n" + stack + "```\n\n"
+	prompt += "The source code list is as follows:\n" + buildFuncListDescription(funs) + "\n"
 	if diag.useChinese {
-		query += "Please reply in Chinese to help analyze the cause of the error and solve it!"
+		prompt += "Please reply in Chinese to help analyze the cause of the error and solve it!"
 	} else {
-		query += "Please help analyze the cause of the error and solve it!"
+		prompt += "Please help analyze the cause of the error and solve it!"
 	}
 
-	answer := diag.BigModel.Chat(query)
-	finish := false
-
-	for !finish {
+	answer := diag.BigModel.Chat(prompt)
+	for finish := false; !finish; {
 		ans := <-answer
 		switch ans.Type {
 		case bigmodel.TypeData:
@@ -117,6 +114,13 @@ func (diag *Diag) Analyze(pnc, stack string, funs []*Function) {
 	println()
 }
 
+func getCallersFrames(max int) *runtime.Frames {
+	pc := make([]uintptr, max)
+	n := runtime.Callers(1, pc)
+	pc = pc[:n]
+	return runtime.CallersFrames(pc)
+}
+
 func buildFuncListDescription(funs []*Function) string {
 	fset := MakeFileFuncSet(funs)
 
diff --git a/example/main.go b/example/main.go
index dc619ed..ab9b01e 100644
--- a/example/main.go
+++ b/example/main.go
@@ -20,12 +20,10 @@
 package main
 
 import (
-	"fmt"
-	"os"
-
 	"github.com/ahaostudy/code-diagnostic/bigmodel"
 	"github.com/ahaostudy/code-diagnostic/diagnostic"
 	"github.com/ahaostudy/code-diagnostic/example/math"
+	"os"
 
 	"github.com/joho/godotenv"
 )
@@ -44,15 +42,23 @@ func init() {
 }
 
 func main() {
-	// initialize a diagnostic tool to automatically capture and analyze program exceptions
-	defer diagnostic.NewDiag(
+	// initialize a diagnostic tool
+	diag := diagnostic.NewDiag(
 		// use the ChatGPT model
 		bigmodel.NewChatGPT(apiKey, bigmodel.WithSpecifyBaseURL(baseURL)),
 		// use chinese
 		diagnostic.WithUseChinese(),
-	).Diagnostic()
+	)
+
+	// automatically capture and analyze program exceptions
+	defer diag.Diagnostic()
+
+	a, b := 10, 0
+	//math.Div(a, b)
 
-	var a, b int
-	a = 20
-	fmt.Println(math.Div(a, b))
+	_, err := math.DivError(a, b)
+	if err != nil {
+		// custom breakpoint analysis
+		diag.BreakPoint(err.Error())
+	}
 }
diff --git a/example/math/math.go b/example/math/math.go
index 40fdae0..580a31e 100644
--- a/example/math/math.go
+++ b/example/math/math.go
@@ -19,6 +19,8 @@
 
 package math
 
+import "fmt"
+
 func Add(a, b int) int {
 	return a + b
 }
@@ -36,3 +38,10 @@ func Div(a, b int) int {
 		return a / b
 	}(a, b)
 }
+
+func DivError(a, b int) (int, error) {
+	if b == 0 {
+		return 0, fmt.Errorf("the divisor can not be zero")
+	}
+	return a / b, nil
+}