fix: report openrouter:unknown when OpenRouter omits the serving provider

routstr/upstream/openrouter.py

@@ -2,6 +2,7 @@ from typing import TYPE_CHECKING
 
 import httpx
 
+from ..core.logging import get_logger
 from ..payment.models import Model, async_fetch_openrouter_models
 from .base import BaseUpstreamProvider, _reported_provider
 from .model_paths import public_provider_url
@@ -9,6 +10,19 @@ from .model_paths import public_provider_url
 if TYPE_CHECKING:
     from ..core.db import UpstreamProviderRow
 
+logger = get_logger(__name__)
+
+_UNKNOWN_SUB_PROVIDER = "unknown"
+
+
+def _carries_usage(payload: dict) -> bool:
+    """Whether a payload holds usage, at top level or in the Anthropic
+    ``message`` / Responses ``response`` envelope."""
+    return any(
+        isinstance(obj, dict) and isinstance(obj.get("usage"), dict)
+        for obj in (payload, payload.get("message"), payload.get("response"))
+    )
+
 
 class OpenRouterUpstreamProvider(BaseUpstreamProvider):
     """Upstream provider specifically configured for OpenRouter API."""
@@ -27,7 +41,8 @@ class OpenRouterUpstreamProvider(BaseUpstreamProvider):
 
         - Real upstream sub-provider (e.g. ``"GMICloud"``) -> ``"openrouter:GMICloud"``.
         - Missing sub-provider, or one that merely echoes ``"openrouter"`` ->
-          ``"unknown"``.
+          ``"openrouter:unknown"``: the router is still known even when the
+          serving provider is not (e.g. the Responses API never reports it).
         - Idempotent: re-stamping never produces ``"openrouter:openrouter:..."``;
           the ``openrouter:`` prefix appears at most once.
         """
@@ -40,9 +55,23 @@ class OpenRouterUpstreamProvider(BaseUpstreamProvider):
         prefix = f"{provider_type}:"
         while sub.lower().startswith(prefix.lower()):
             sub = sub[len(prefix) :].strip()
+        # Already stamped as unknown on an earlier pass; keep it without
+        # warning again.
+        if sub.lower() == _UNKNOWN_SUB_PROVIDER:
+            response_json["provider"] = f"{provider_type}:{_UNKNOWN_SUB_PROVIDER}"
+            return
         # No real sub-provider, or it just echoes our own router name.
         if not sub or sub.lower() == provider_type.lower():
-            response_json["provider"] = "unknown"
+            # Warn only on the billed payload, not on every stream chunk.
+            if _carries_usage(response_json):
+                logger.warning(
+                    "OpenRouter did not report the serving provider",
+                    extra={
+                        "model": response_json.get("model"),
+                        "response_id": response_json.get("id"),
+                    },
+                )
+            response_json["provider"] = f"{provider_type}:{_UNKNOWN_SUB_PROVIDER}"
             return
         response_json["provider"] = f"{provider_type}:{sub}"
 

tests/unit/test_provider_field_injection.py

@@ -1,3 +1,5 @@
+from unittest.mock import patch
+
 from routstr.upstream.anthropic import AnthropicUpstreamProvider
 from routstr.upstream.base import BaseUpstreamProvider
 from routstr.upstream.generic import GenericUpstreamProvider
@@ -33,12 +35,12 @@ def test_apply_provider_field_openrouter_passthrough() -> None:
 
 
 def test_apply_provider_field_openrouter_no_upstream_provider() -> None:
-    """If OpenRouter omits the provider field, the real serving provider is
-    unknown — a bare ``openrouter`` value carries no information."""
+    """If OpenRouter omits the provider field, the serving provider is
+    unknown but the router is not."""
     p = _make_provider(OpenRouterUpstreamProvider, "openrouter")
     data: dict = {"id": "gen-abc"}
     p._apply_provider_field(data)
-    assert data["provider"] == "unknown"
+    assert data["provider"] == "openrouter:unknown"
 
 
 def test_apply_provider_field_openrouter_echoes_router_name() -> None:
@@ -46,7 +48,35 @@ def test_apply_provider_field_openrouter_echoes_router_name() -> None:
     p = _make_provider(OpenRouterUpstreamProvider, "openrouter")
     data: dict = {"provider": "openrouter"}
     p._apply_provider_field(data)
-    assert data["provider"] == "unknown"
+    assert data["provider"] == "openrouter:unknown"
+
+
+def test_apply_provider_field_openrouter_unknown_is_idempotent() -> None:
+    """Re-stamping an unknown payload (e.g. in inject_cost_metadata) keeps
+    ``openrouter:unknown`` instead of reading ``unknown`` as a sub-provider."""
+    p = _make_provider(OpenRouterUpstreamProvider, "openrouter")
+    data: dict = {"id": "gen-abc"}
+    p._apply_provider_field(data)
+    p._apply_provider_field(data)
+    assert data["provider"] == "openrouter:unknown"
+
+
+def test_apply_provider_field_openrouter_warns_once_on_billed_payload() -> None:
+    """A missing provider is logged on the payload carrying usage, not on
+    every stream chunk or on a re-stamp."""
+    p = _make_provider(OpenRouterUpstreamProvider, "openrouter")
+    chunk: dict = {"type": "response.output_text.delta", "delta": "hi"}
+    completed: dict = {
+        "type": "response.completed",
+        "response": {"id": "gen-abc", "usage": {"input_tokens": 1}},
+    }
+    with patch("routstr.upstream.openrouter.logger.warning") as warning:
+        p._apply_provider_field(chunk)
+        p._apply_provider_field(completed)
+        p._apply_provider_field(completed)
+
+    warning.assert_called_once()
+    assert chunk["provider"] == completed["provider"] == "openrouter:unknown"
 
 
 def test_apply_provider_field_openrouter_idempotent_no_double_prefix() -> None:
@@ -79,14 +109,14 @@ def test_apply_provider_field_blank_upstream_treated_as_missing() -> None:
     p = _make_provider(OpenRouterUpstreamProvider, "openrouter")
     data: dict = {"provider": "   "}
     p._apply_provider_field(data)
-    assert data["provider"] == "unknown"
+    assert data["provider"] == "openrouter:unknown"
 
 
 def test_apply_provider_field_non_string_upstream_treated_as_missing() -> None:
     p = _make_provider(OpenRouterUpstreamProvider, "openrouter")
     data: dict = {"provider": 42}
     p._apply_provider_field(data)
-    assert data["provider"] == "unknown"
+    assert data["provider"] == "openrouter:unknown"
 
 
 def test_apply_provider_field_openrouter_reads_nested_envelopes() -> None: