fix(cli): validate user-defined providers consistently

hermes_cli/main.py

@@ -1429,6 +1429,7 @@ def select_provider_and_model(args=None):
         load_config,
         get_env_value,
     )
+    from hermes_cli.providers import resolve_provider_full
 
     config = load_config()
     current_model = config.get("model")
@@ -1446,14 +1447,30 @@ def select_provider_and_model(args=None):
     effective_provider = (
         config_provider or os.getenv("HERMES_INFERENCE_PROVIDER") or "auto"
     )
-    try:
-        active = resolve_provider(effective_provider)
-    except AuthError as exc:
-        warning = format_auth_error(exc)
-        print(f"Warning: {warning} Falling back to auto provider detection.")
+    compatible_custom_providers = get_compatible_custom_providers(config)
+    active = None
+    if effective_provider != "auto":
+        active_def = resolve_provider_full(
+            effective_provider,
+            config.get("providers"),
+            compatible_custom_providers,
+        )
+        if active_def is not None:
+            active = active_def.id
+        else:
+            warning = (
+                f"Unknown provider '{effective_provider}'. Check 'hermes model' for "
+                "available providers, or run 'hermes doctor' to diagnose config "
+                "issues."
+            )
+            print(f"Warning: {warning} Falling back to auto provider detection.")
+    if active is None:
         try:
             active = resolve_provider("auto")
-        except AuthError:
+        except AuthError as exc:
+            if effective_provider == "auto":
+                warning = format_auth_error(exc)
+                print(f"Warning: {warning} Falling back to auto provider detection.")
             active = None  # no provider yet; default to first in list
 
     # Detect custom endpoint