diff --git a/src/index.ts b/src/index.ts
index 08213c3..e9f0b3a 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -30,6 +30,8 @@ const args = yargs
 const loz = new Loz();
 
 async function handleLozCommand(): Promise<void> {
+  if (args.attribution) loz.attribution = true;
+
   // If the stdin is a TTY
   // when runnig unit tests for running Linux commands, stdin is not a TTY
   // so we need isRunningInMocha to check if we are running unit tests.
@@ -43,8 +45,6 @@ async function handleLozCommand(): Promise<void> {
     // Input from a pipe
     if (args.git) {
       await handleCodeDiffFromPipe();
-    } else if (args.attribution) {
-      loz.attribution = true;
     } else {
       //console.log("Run loz like this: git diff | loz --git");
       if (args.prompt !== undefined) {
diff --git a/test/git.test.ts b/test/git.test.ts
index 5b98efe..1e04b2a 100644
--- a/test/git.test.ts
+++ b/test/git.test.ts
@@ -70,6 +70,17 @@ describe("Test git operations", function () {
     execSync("sed -i 's/Hell/Hello/g' hello.c");
     const log = execSync(`git diff | node ${LOZ_BIN} -g`).toString();
     expect(log).to.include("typo");
+    // Do not append "Generated by Model Name" to the commit message by default.
+    expect(log.indexOf("Generated by")).equal(-1);
+  });
+
+  // git diff | loz -g -a
+  it("append 'Generated by gpt-3.5-turbo'", function () {
+    this.timeout(5000);
+    const log = execSync(`git diff | node ${LOZ_BIN} -g -a`).toString();
+    expect(log).to.include("typo");
+    // Append "Generated by Model Name" to the commit message. (-a option is used)
+    expect(log).to.include("Generated by");
   });
 
   // LOZ=true git commit