diff --git a/CHANGELOG.md b/CHANGELOG.md
index fbf2233..9f6ddb3 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,19 @@
 
 ## 2026-04-06
 
+### Windows ASR 默认改成 GPU 优先与自动语言识别
+
+- Windows `ASR HTTP` 现在默认不再强锁 `zh + cpu + int8`，而是改成：
+  - `WHISPER_DEVICE=auto`
+  - `WHISPER_LANGUAGE=auto`
+  - `WHISPER_COMPUTE_TYPE=auto`
+- 运行时会优先尝试 `cuda + int8_float16`，如果当前机器没有可用 GPU，再自动回退到 `cpu + int8`。
+- 转写请求默认不再强制指定语言，这样一句话里中英混说时，会按模型自动识别而不是强压成中文模式。
+- 健康接口现在也会明确返回：
+  - 配置层 `language/device/compute_type`
+  - 实际加载后的 `active_device/active_compute_type`
+  便于区分“当前策略”和“本轮真实用到的运行模式”。
+
 ### NAS collector 改走服务器本机的 n8n 与火爆视频
 
 - 新增 `fnOS -> 公网服务器` 的本地转发隧道，把服务器本机 `127.0.0.1:25670/25678` 分别映射到 NAS 的 `19570/19578`。
diff --git a/deploy/storyforge-windows-asr-http/app.py b/deploy/storyforge-windows-asr-http/app.py
index 5e80f61..ed4996f 100644
--- a/deploy/storyforge-windows-asr-http/app.py
+++ b/deploy/storyforge-windows-asr-http/app.py
@@ -10,9 +10,6 @@ from fastapi import FastAPI, File, UploadFile
 from fastapi.responses import JSONResponse
 
 MODEL_NAME = os.getenv("WHISPER_MODEL", "base")
-LANGUAGE = os.getenv("WHISPER_LANGUAGE", "zh")
-DEVICE = os.getenv("WHISPER_DEVICE", "cpu")
-COMPUTE_TYPE = os.getenv("WHISPER_COMPUTE_TYPE", "int8")
 BEAM_SIZE = int(os.getenv("WHISPER_BEAM_SIZE", "5"))
 VAD_FILTER = os.getenv("WHISPER_VAD_FILTER", "1").strip().lower() not in {"0", "false", "no"}
 DOWNLOAD_ROOT = Path(os.getenv("WHISPER_DOWNLOAD_ROOT", str(Path(__file__).resolve().parent / "models-cache")))
@@ -20,17 +17,59 @@ DOWNLOAD_ROOT = Path(os.getenv("WHISPER_DOWNLOAD_ROOT", str(Path(__file__).resol
 app = FastAPI(title="storyforge-windows-asr", version="1.0.0")
 
 
+def describe_language_mode() -> str:
+    value = (os.getenv("WHISPER_LANGUAGE", "") or "").strip()
+    if not value or value.lower() in {"auto", "detect"}:
+        return "auto"
+    return value
+
+
+def resolve_language() -> str | None:
+    value = describe_language_mode()
+    return None if value == "auto" else value
+
+
+def describe_device_mode() -> str:
+    value = (os.getenv("WHISPER_DEVICE", "") or "").strip().lower()
+    return value or "auto"
+
+
+def describe_compute_mode() -> str:
+    value = (os.getenv("WHISPER_COMPUTE_TYPE", "") or "").strip()
+    return value or "auto"
+
+
+def build_runtime_profiles() -> list[tuple[str, str]]:
+    device = describe_device_mode()
+    compute = describe_compute_mode()
+    if device != "auto":
+        return [(device, compute if compute != "auto" else "int8")]
+    if compute != "auto":
+        return [("cuda", compute), ("cpu", compute)]
+    return [("cuda", "int8_float16"), ("cpu", "int8")]
+
+
 @lru_cache(maxsize=1)
 def get_model():
     from faster_whisper import WhisperModel
 
     DOWNLOAD_ROOT.mkdir(parents=True, exist_ok=True)
-    return WhisperModel(
-        MODEL_NAME,
-        device=DEVICE,
-        compute_type=COMPUTE_TYPE,
-        download_root=str(DOWNLOAD_ROOT),
-    )
+    last_error: Exception | None = None
+    for device, compute_type in build_runtime_profiles():
+        try:
+            model = WhisperModel(
+                MODEL_NAME,
+                device=device,
+                compute_type=compute_type,
+                download_root=str(DOWNLOAD_ROOT),
+            )
+            app.state.runtime_device = device
+            app.state.runtime_compute_type = compute_type
+            return model
+        except Exception as exc:  # pragma: no cover - exercised on real hosts
+            last_error = exc
+    assert last_error is not None
+    raise last_error
 
 
 @app.get("/health")
@@ -39,9 +78,11 @@ def health() -> dict[str, object]:
         "status": "ok",
         "service": "storyforge-windows-asr",
         "model_name": MODEL_NAME,
-        "language": LANGUAGE,
-        "device": DEVICE,
-        "compute_type": COMPUTE_TYPE,
+        "language": describe_language_mode(),
+        "device": describe_device_mode(),
+        "compute_type": describe_compute_mode(),
+        "active_device": getattr(app.state, "runtime_device", ""),
+        "active_compute_type": getattr(app.state, "runtime_compute_type", ""),
         "download_root": str(DOWNLOAD_ROOT),
         "model_loaded": get_model.cache_info().currsize > 0,
     }
@@ -62,9 +103,9 @@ async def transcribe(wav: UploadFile = File(...)):
 
     try:
         model = get_model()
-        segments, _info = model.transcribe(
+        segments, info = model.transcribe(
             str(temp_path),
-            language=LANGUAGE or None,
+            language=resolve_language(),
             beam_size=max(1, BEAM_SIZE),
             vad_filter=VAD_FILTER,
         )
@@ -74,6 +115,8 @@ async def transcribe(wav: UploadFile = File(...)):
             "text": text,
             "success": bool(text),
             "duration_ms": duration_ms,
+            "detected_language": getattr(info, "language", None),
+            "detected_language_probability": getattr(info, "language_probability", None),
             "error_message": None if text else "empty transcription",
         }
     except Exception as exc:
diff --git a/deploy/storyforge-windows-asr-http/run.ps1 b/deploy/storyforge-windows-asr-http/run.ps1
index 81509f3..9b26616 100644
--- a/deploy/storyforge-windows-asr-http/run.ps1
+++ b/deploy/storyforge-windows-asr-http/run.ps1
@@ -13,9 +13,9 @@ $venvPython = Join-Path $venvDir "Scripts\python.exe"
 & $venvPython -m pip install -r (Join-Path $scriptDir "requirements.txt")
 
 $env:WHISPER_MODEL = if ($env:WHISPER_MODEL) { $env:WHISPER_MODEL } else { "base" }
-$env:WHISPER_LANGUAGE = if ($env:WHISPER_LANGUAGE) { $env:WHISPER_LANGUAGE } else { "zh" }
-$env:WHISPER_DEVICE = if ($env:WHISPER_DEVICE) { $env:WHISPER_DEVICE } else { "cpu" }
-$env:WHISPER_COMPUTE_TYPE = if ($env:WHISPER_COMPUTE_TYPE) { $env:WHISPER_COMPUTE_TYPE } else { "int8" }
+$env:WHISPER_LANGUAGE = if ($env:WHISPER_LANGUAGE) { $env:WHISPER_LANGUAGE } else { "" }
+$env:WHISPER_DEVICE = if ($env:WHISPER_DEVICE) { $env:WHISPER_DEVICE } else { "auto" }
+$env:WHISPER_COMPUTE_TYPE = if ($env:WHISPER_COMPUTE_TYPE) { $env:WHISPER_COMPUTE_TYPE } else { "" }
 $env:WHISPER_BEAM_SIZE = if ($env:WHISPER_BEAM_SIZE) { $env:WHISPER_BEAM_SIZE } else { "5" }
 $env:WHISPER_VAD_FILTER = if ($env:WHISPER_VAD_FILTER) { $env:WHISPER_VAD_FILTER } else { "1" }
 $env:WHISPER_DOWNLOAD_ROOT = if ($env:WHISPER_DOWNLOAD_ROOT) { $env:WHISPER_DOWNLOAD_ROOT } else { (Join-Path $scriptDir "models-cache") }
diff --git a/tests/test_windows_asr_http.py b/tests/test_windows_asr_http.py
new file mode 100644
index 0000000..685d6b9
--- /dev/null
+++ b/tests/test_windows_asr_http.py
@@ -0,0 +1,71 @@
+from __future__ import annotations
+
+import importlib.util
+import os
+import unittest
+from pathlib import Path
+
+from fastapi.testclient import TestClient
+
+
+ROOT = Path(__file__).resolve().parents[1]
+APP_PATH = ROOT / "deploy" / "storyforge-windows-asr-http" / "app.py"
+
+
+def load_windows_asr_app():
+    spec = importlib.util.spec_from_file_location("storyforge_windows_asr_app", APP_PATH)
+    module = importlib.util.module_from_spec(spec)
+    assert spec and spec.loader
+    spec.loader.exec_module(module)
+    return module
+
+
+class WindowsAsrHttpTests(unittest.TestCase):
+    def setUp(self) -> None:
+        self._saved = {key: os.environ.get(key) for key in [
+            "WHISPER_LANGUAGE",
+            "WHISPER_DEVICE",
+            "WHISPER_COMPUTE_TYPE",
+        ]}
+
+    def tearDown(self) -> None:
+        for key, value in self._saved.items():
+            if value is None:
+                os.environ.pop(key, None)
+            else:
+                os.environ[key] = value
+
+    def test_defaults_prefer_auto_language_and_gpu_first_profiles(self) -> None:
+        os.environ.pop("WHISPER_LANGUAGE", None)
+        os.environ.pop("WHISPER_DEVICE", None)
+        os.environ.pop("WHISPER_COMPUTE_TYPE", None)
+
+        module = load_windows_asr_app()
+
+        self.assertIsNone(module.resolve_language())
+        self.assertEqual(module.describe_language_mode(), "auto")
+        self.assertEqual(
+            module.build_runtime_profiles(),
+            [("cuda", "int8_float16"), ("cpu", "int8")],
+        )
+
+        client = TestClient(module.app)
+        try:
+            payload = client.get("/health").json()
+        finally:
+            client.close()
+
+        self.assertEqual(payload["language"], "auto")
+        self.assertEqual(payload["device"], "auto")
+        self.assertEqual(payload["compute_type"], "auto")
+
+    def test_explicit_runtime_overrides_are_respected(self) -> None:
+        os.environ["WHISPER_LANGUAGE"] = "zh"
+        os.environ["WHISPER_DEVICE"] = "cpu"
+        os.environ["WHISPER_COMPUTE_TYPE"] = "int8"
+
+        module = load_windows_asr_app()
+
+        self.assertEqual(module.resolve_language(), "zh")
+        self.assertEqual(module.describe_language_mode(), "zh")
+        self.assertEqual(module.build_runtime_profiles(), [("cpu", "int8")])