fix: YouTube JS runtime check, Douyin health check, cli bare except, config permission race (#104)

- YouTube: warn when only Node.js is installed but yt-dlp config file
  is missing (previously returned "ok" incorrectly)
- Douyin: use `mcporter list` instead of calling with a hardcoded
  invalid share URL that always fails
- cli: replace bare `except:` with `except Exception:` in
  `_detect_environment` to avoid catching KeyboardInterrupt/SystemExit
- cli: fix unclosed file handle for cloud VM detection
- config: use `os.open()` with 0o600 mode to eliminate permission
  race window when saving credentials

agent_reach/channels/douyin.py

@@ -42,13 +42,15 @@ class DouyinChannel(Channel):
                 )
         except Exception:
             return "off", "mcporter 连接异常"
+        # Verify MCP connectivity by listing available tools instead of
+        # calling with a hardcoded (invalid) share link that always fails.
         try:
             r = subprocess.run(
-                [mcporter, "call", "douyin.parse_douyin_video_info(share_link: \"https://www.douyin.com\")"],
+                [mcporter, "list", "douyin"],
                 capture_output=True, encoding="utf-8", errors="replace", timeout=15
             )
-            if r.returncode == 0:
+            if r.returncode == 0 and r.stdout.strip():
                 return "ok", "完整可用（视频解析、下载链接获取）"
-            return "warn", "MCP 已连接但调用异常，检查 douyin-mcp-server 服务是否在运行"
+            return "warn", "MCP 已连接但工具列表为空，检查 douyin-mcp-server 服务是否在运行"
         except Exception:
             return "warn", "MCP 连接异常，检查 douyin-mcp-server 服务是否在运行"

agent_reach/channels/youtube.py

@@ -28,13 +28,17 @@ class YouTubeChannel(Channel):
                 "  安装 Node.js 或 deno，然后运行：agent-reach install"
             )
         # Check yt-dlp config for --js-runtimes
-        ytdlp_config = os.path.expanduser("~/.config/yt-dlp/config")
+        # Deno works out of the box; Node.js requires explicit config
         has_deno = shutil.which("deno")
-        if not has_deno and os.path.exists(ytdlp_config):
-            with open(ytdlp_config, "r") as f:
-                if "--js-runtimes" not in f.read():
-                    return "warn", (
-                        "yt-dlp 已安装但未配置 JS runtime。运行：\n"
-                        "  mkdir -p ~/.config/yt-dlp && echo '--js-runtimes node' >> ~/.config/yt-dlp/config"
-                    )
+        if not has_deno:
+            ytdlp_config = os.path.expanduser("~/.config/yt-dlp/config")
+            has_js_config = False
+            if os.path.exists(ytdlp_config):
+                with open(ytdlp_config, "r") as f:
+                    has_js_config = "--js-runtimes" in f.read()
+            if not has_js_config:
+                return "warn", (
+                    "yt-dlp 已安装但未配置 JS runtime。运行：\n"
+                    "  mkdir -p ~/.config/yt-dlp && echo '--js-runtimes node' >> ~/.config/yt-dlp/config"
+                )
         return "ok", "可提取视频信息和字幕"

agent_reach/cli.py

@@ -720,10 +720,11 @@ def _detect_environment():
     for cloud_file in ["/sys/hypervisor/uuid", "/sys/class/dmi/id/product_name"]:
         if os.path.exists(cloud_file):
             try:
-                content = open(cloud_file).read().lower()
+                with open(cloud_file) as f:
+                    content = f.read().lower()
                 if any(x in content for x in ["amazon", "google", "microsoft", "digitalocean", "linode", "vultr", "hetzner"]):
                     indicators += 2
-            except:
+            except Exception:
                 pass
 
     # systemd-detect-virt
@@ -732,7 +733,7 @@ def _detect_environment():
         result = subprocess.run(["systemd-detect-virt"], capture_output=True, encoding="utf-8", errors="replace", timeout=3)
         if result.returncode == 0 and result.stdout.strip() != "none":
             indicators += 1
-    except:
+    except Exception:
         pass
 
     return "server" if indicators >= 2 else "local"

agent_reach/config.py

@@ -49,14 +49,22 @@ class Config:
     def save(self):
         """Save config to YAML file."""
         self._ensure_dir()
-        with open(self.config_path, "w", encoding="utf-8") as f:
-            yaml.dump(self.data, f, default_flow_style=False, allow_unicode=True)
-        # Restrict permissions — config may contain credentials
+        # Create file with restricted permissions from the start to avoid
+        # a race window where credentials are briefly world-readable.
         try:
             import stat
-            self.config_path.chmod(stat.S_IRUSR | stat.S_IWUSR)  # 0o600
+            fd = os.open(
+                str(self.config_path),
+                os.O_WRONLY | os.O_CREAT | os.O_TRUNC,
+                stat.S_IRUSR | stat.S_IWUSR,  # 0o600
+            )
+            with os.fdopen(fd, "w", encoding="utf-8") as f:
+                yaml.dump(self.data, f, default_flow_style=False, allow_unicode=True)
         except OSError:
-            pass  # Windows or permission edge cases
+            # Fallback for Windows or other edge cases where os.open flags
+            # are not fully supported.
+            with open(self.config_path, "w", encoding="utf-8") as f:
+                yaml.dump(self.data, f, default_flow_style=False, allow_unicode=True)
 
     def get(self, key: str, default: Any = None) -> Any:
         """Get a config value. Also checks environment variables (uppercase)."""