fix: Updated system prompt for GitCommitGPT-4 to improve commit messa…

…ge content.

README.md

@@ -14,7 +14,17 @@ AI-Commit is a command line tool that uses OpenAI's language generation capabili
 
 ## Prerequisites
 
-To use AI-Commit, you need to obtain an API key from OpenAI and set it as the value of the OPENAI_API_KEY environment variable.
+To use AI-Commit, you need to obtain an API key from OpenAI and set it as the value of the `OPENAI_API_KEY` environment variable.
+
+```
+export OPENAI_API_KEY=sk-xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+```
+
+Sometime, the ChatGPT's response is not good (too long, too short, not meaningful). In that case, you can try custom the system prompt by set the `AI_COMMIT_SYSTEM_PROMPT` environment variable:
+
+```
+export AI_COMMIT_SYSTEM_PROMPT="You are a GitCommitGPT-4, You will help user to write commit message, commit message should be short (less than 100 chars), clean and meaningful. Only response the message."
+```
 
 Note: Using AI-Commit will result in charges from OpenAI for API usage, so be sure to understand their pricing model before use.
 

main.go

@@ -11,12 +11,7 @@ import (
 	"time"
 )
 
-var messages = []*Message{
-	{
-		Role:    "system",
-		Content: `You are a GitCommitGPT-4, You will help user to write commit message, do not talk anything else the commit message. Your commit message is short, clean and meaningful.`,
-	},
-}
+var messages []*Message
 
 func main() {
 	// prepare the arguments
@@ -26,6 +21,18 @@ func main() {
 		os.Exit(1)
 	}
 
+	systemPrompt := os.Getenv("AI_COMMIT_SYSTEM_PROMPT")
+	if systemPrompt == "" {
+		systemPrompt = `You are a GitCommitGPT-4, You will help user to write commit message, commit message should be short (less than 100 chars), clean and meaningful. Only response the message.`
+	}
+
+	messages = []*Message{
+		{
+			Role:    "system",
+			Content: systemPrompt,
+		},
+	}
+
 	client := NewGptClient(apiKey)
 
 	// prepare the diff
@@ -68,7 +75,7 @@ func main() {
 
 	messages = append(messages, &Message{
 		Role:    "user",
-		Content: "Write commit message for this git diff output: \n\n" + diff,
+		Content: "Write commit message for the following git diff: \n\n```" + diff + "\n\n```",
 	})
 
 	for {