fix(models): a vendor's own id on its first-party provider never re-routes

215fd0ecb9 made the current provider's live catalog outrank static
guesses, but a live catalog that could not be fetched (Codex outage, cold
cache) looked identical to "not served", so `/model gpt-6-astra` on
openai-codex still walked to OpenRouter (which relists every vendor)
whenever an OpenRouter key existed. Same shape for grok-* on xai-oauth
and claude-* on anthropic.

detect_provider_for_model now treats a vendor id typed on that vendor's
single-vendor first-party provider as a selection: stay, let the vendor
accept or reject it (the existing "not found in listing" note still
fires). Cross-vendor remaps (claude id on Codex -> keyed OpenRouter) and
aggregator / custom / multi-vendor reseller sessions are unchanged.

hermes_cli/models.py

@@ -938,7 +938,8 @@ def detect_provider_for_model(
     skipped and the ladder continues (``None`` = stay on the current provider). Exceptions: the user
     NAMED the provider (``/model nous``), or there is no current provider yet (``auto``) — then the
     first guess is returned so the credential step fails loudly instead of silently ignoring input."""
-    from hermes_cli.models_detect import current_provider_catalog_match, provider_has_credentials
+    from hermes_cli.models_detect import (
+        current_provider_catalog_match, current_provider_owns_vendor, provider_has_credentials)
 
     name = (model_name or "").strip()
     if not name:
@@ -950,6 +951,10 @@ def detect_provider_for_model(
     served = current_provider_catalog_match(name, current_provider)
     if served is not None:
         return (current_provider, served) if served != name else None
+    # Live catalog unavailable or lagging: the vendor's own id on the vendor's first-party provider
+    # is still a selection — an aggregator relisting it is not grounds to switch.
+    if current_provider_owns_vendor(name, current_provider):
+        return None
 
     no_selection = (current_provider or "").strip().lower() in {"", "auto"}
     for candidate in _detection_candidates(name, current_provider):

hermes_cli/models_detect.py

@@ -44,6 +44,31 @@ def current_provider_catalog_match(model_name: str, current_provider: str) -> Op
         (mid for mid in catalog if "/" in mid and mid.split("/", 1)[1].lower() == wanted), None)
 
 
+def current_provider_owns_vendor(model_name: str, current_provider: str) -> bool:
+    """True when *model_name* belongs to the vendor a single-vendor first-party provider natively
+    serves (``gpt-6-astra`` on ``openai-codex``, ``grok-4.6`` on ``xai-oauth``).
+
+    A first-party session plus that vendor's own id is a selection, not a guess: when the live
+    catalog could not confirm the id (fetch failed, static fallback lags an early-access rollout)
+    the answer is "stay and let the vendor accept or reject it", never "a reseller lists it, so
+    switch there". Aggregators, custom endpoints and multi-vendor resellers (nvidia, alibaba, ...)
+    have no single native vendor and are skipped."""
+    from hermes_cli.model_normalize import detect_vendor
+    from hermes_cli.models import _AGGREGATOR_PROVIDERS, _PROVIDER_MODELS, normalize_provider
+
+    provider = (current_provider or "").strip().lower()
+    if provider in _SKIP or provider.startswith("custom:"):
+        return False
+    normalized = normalize_provider(provider)
+    if normalized in _SKIP or normalized in _AGGREGATOR_PROVIDERS:
+        return False
+    vendor = detect_vendor(model_name or "")
+    if not vendor:
+        return False
+    native = {detect_vendor(mid) for mid in _PROVIDER_MODELS.get(normalized, ())} - {None}
+    return native == {vendor}
+
+
 def provider_has_credentials(provider: str) -> bool:
     """Whether *provider* can be switched to without the user typing a key: env/.env key, auth
     store login, or a usable credential-pool entry. ``custom``/``custom:*`` targets only come out