🚧 WIP

src/opcda_diagnozer/config.py

@@ -276,9 +276,11 @@ def _validate(config: Config) -> None:
         )
     if config.opc.connect_timeout_s <= 0:
         raise ConfigError(f"opc.connect_timeout_s: must be > 0, got {config.opc.connect_timeout_s}")
-    if not config.tags:
+    if not config.tags and not config.devices:
         raise ConfigError(
-            "tags: at least one tag is required — without tags there is nothing to monitor"
+            "tags: nothing to monitor - define at least one tag or device "
+            "indicator (devices: entries alone are fine, tags: entries alone "
+            "are fine; both empty means the tool would read nothing)"
         )
     names = [t.name for t in config.tags]
     duplicates = sorted({n for n in names if names.count(n) > 1})

src/opcda_diagnozer/main.py

@@ -225,6 +225,8 @@ def _cmd_check_config(config_path: str) -> int:
         print(f"  devices: {len(config.devices)} link indicator(s):")
         for device in config.devices:
             print(f"    {device.name} <- {device.tag}")
+    if not config.tags and config.devices:
+        print("  note:   no surveillance tags - monitoring device links only")
     print(f"  poll:   every {config.poll.interval_s} s, hang flagged after {config.poll.timeout_ms} ms")
     return 0