diff --git a/.dockerignore b/.dockerignore
index 45b0f8d..9a5c2ee 100644
--- a/.dockerignore
+++ b/.dockerignore
@@ -1,7 +1,8 @@
 *.exe
 *.md
 .env
-.env.example
+.env.*
+!.env.example
 .git
 .gitignore
 tts_api_architecture.html
diff --git a/.gitignore b/.gitignore
index e7ef1d8..8735742 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,4 +1,4 @@
-# Go build cache
+# Go build cache
 .gocache/
 *.exe
 *.test
@@ -11,4 +11,9 @@
 Thumbs.db
 
 # Logs
-*.log
\ No newline at end of file
+*.log
+
+# Secrets (do NOT commit local .env files; keep .env.example tracked as template)
+.env
+.env.*
+!.env.example
\ No newline at end of file
diff --git a/adapter/volcano/synthesis.go b/adapter/volcano/synthesis.go
index 07ccbaa..5a461da 100644
--- a/adapter/volcano/synthesis.go
+++ b/adapter/volcano/synthesis.go
@@ -116,7 +116,14 @@ func Synthesis(
 	duration := time.Since(started)
 
 	finalData := parsed.AudioData
+	// finalFormat 反映真实输出格式(用于 controller 写 Content-Type):
+	//   - wav 走 pcm 上游 + 本地拼头,对外仍是 wav
+	//   - aac/flac 在上方已被上游降级为 mp3,真实输出也是 mp3
+	//   - 其余与 clientFormat 一致
 	finalFormat := clientFormat
+	if clientFormat != "wav" {
+		finalFormat = opts.Format
+	}
 	sampleRate := opts.SampleRate
 	if clientFormat == "wav" {
 		wav, wrapErr := WrapWAVHeader(parsed.AudioData, opts.SampleRate)