fix: stop reporting OpenRouter provider as unknown on stream and envelope payloads

The OpenRouter stamper wrote "unknown" whenever a payload lacked a
top-level provider. That hit every Anthropic /messages event, every
Responses event, and the usage/cost payloads routstr synthesizes at the
end of a stream.

- Read the provider from the Anthropic `message` and Responses
  `response` envelopes as well as the top level.
- Carry the provider reported earlier in a stream to later events and
  to the synthesized usage/cost payloads.

routstr/upstream/base.py

@@ -214,6 +214,20 @@ def _responses_usage_payload(data_json: dict) -> dict:
     return nested if isinstance(nested, dict) else data_json
 
 
+def _reported_provider(payload: dict) -> str | None:
+    """Provider named by an upstream payload, if any.
+
+    Checked at top level first, then inside the Anthropic ``message`` and
+    Responses ``response`` envelopes, which is where those dialects nest it.
+    """
+    for obj in (payload, payload.get("message"), payload.get("response")):
+        if isinstance(obj, dict):
+            value = obj.get("provider")
+            if isinstance(value, str) and value.strip():
+                return value.strip()
+    return None
+
+
 def _render_sse_event(field_lines: list[str], data: str) -> str:
     """Re-frame one parsed event, re-prefixing every line of a multi-line data."""
     body = "".join(f"{line}\n" for line in field_lines)
@@ -485,8 +499,7 @@ class BaseUpstreamProvider:
             return
         response_json["provider_url"] = public_provider_url(self.base_url)
         provider_type = (self.provider_type or "").strip()
-        existing = response_json.get("provider")
-        existing_str = existing.strip() if isinstance(existing, str) else ""
+        existing_str = _reported_provider(response_json) or ""
         if not existing_str:
             response_json["provider"] = provider_type
             return
@@ -498,6 +511,17 @@ class BaseUpstreamProvider:
             return
         response_json["provider"] = f"{provider_type}:{existing_str}"
 
+    def _stamp_streamed_provider(
+        self, payload: dict, carried: str | None
+    ) -> str | None:
+        """Stamp a streamed payload, falling back to a provider an earlier event
+        reported. Returns the provider to carry forward to later payloads."""
+        reported = _reported_provider(payload)
+        if reported is None and carried is not None:
+            payload["provider"] = carried
+        self._apply_provider_field(payload)
+        return reported or carried
+
     def _log_full_refund(
         self,
         *,
@@ -1169,6 +1193,7 @@ class BaseUpstreamProvider:
 
         usage_finalized = False
         last_model_seen: str | None = None
+        provider_seen: str | None = None
 
         async def finalize_db_only() -> None:
             nonlocal usage_finalized
@@ -1243,6 +1268,7 @@ class BaseUpstreamProvider:
                   end of stream.
                 """
                 nonlocal last_model_seen, usage_chunk_data, done_seen, stream_id
+                nonlocal provider_seen
 
                 event = raw_event.strip(b"\r\n")
                 if not event:
@@ -1282,7 +1308,7 @@ class BaseUpstreamProvider:
 
                 if isinstance(obj, dict):
                     usage_estimator.observe(obj)
-                    self._apply_provider_field(obj)
+                    provider_seen = self._stamp_streamed_provider(obj, provider_seen)
                     if obj.get("model"):
                         last_model_seen = str(obj.get("model"))
                     if requested_model:
@@ -1408,6 +1434,7 @@ class BaseUpstreamProvider:
                                 if legacy_completion
                                 else "chat.completion.chunk",
                                 "model": last_model_seen or "unknown",
+                                "provider": provider_seen,
                                 "choices": [],
                                 "usage": {
                                     "prompt_tokens": cost_data.get("input_tokens", 0),
@@ -1652,6 +1679,7 @@ class BaseUpstreamProvider:
 
         usage_finalized = False
         last_model_seen: str | None = None
+        provider_seen: str | None = None
 
         async def finalize_db_only() -> None:
             nonlocal usage_finalized
@@ -1715,7 +1743,7 @@ class BaseUpstreamProvider:
                 and preserves ``event:``/``id:`` fields attached to their data
                 line so Responses API event framing stays intact.
                 """
-                nonlocal last_model_seen, usage_chunk_data, done_seen
+                nonlocal last_model_seen, usage_chunk_data, done_seen, provider_seen
                 nonlocal reasoning_tokens
 
                 event = raw_event.strip(b"\r\n")
@@ -1751,7 +1779,7 @@ class BaseUpstreamProvider:
                 obj = json_codec.loads(data)
 
                 if isinstance(obj, dict):
-                    self._apply_provider_field(obj)
+                    provider_seen = self._stamp_streamed_provider(obj, provider_seen)
                     if obj.get("model"):
                         last_model_seen = str(obj.get("model"))
                     if requested_model:
@@ -1840,6 +1868,7 @@ class BaseUpstreamProvider:
                         if usage_chunk_data is None:
                             usage_chunk_data = {
                                 "type": "response.completed",
+                                "provider": provider_seen,
                                 "response": {
                                     "model": last_model_seen or "unknown",
                                     "usage": {
@@ -2195,6 +2224,7 @@ class BaseUpstreamProvider:
         usage_estimator = MissingUsageEstimator(request_body, model_obj)
         usage_finalized = False
         last_model_seen: str | None = None
+        provider_seen: str | None = None
 
         async def finalize_without_usage() -> bytes | None:
             nonlocal usage_finalized
@@ -2244,7 +2274,7 @@ class BaseUpstreamProvider:
         async def stream_with_cost(
             max_cost_for_model: int,
         ) -> AsyncGenerator[bytes, None]:
-            nonlocal usage_finalized, last_model_seen
+            nonlocal usage_finalized, last_model_seen, provider_seen
             stored_chunks: list[bytes] = []
             input_tokens: int = 0
             output_tokens: int = 0
@@ -2301,7 +2331,9 @@ class BaseUpstreamProvider:
                                             last_model_seen = str(msg.get("model"))
 
                                         provider_added = "provider" not in data
-                                        self._apply_provider_field(data)
+                                        provider_seen = self._stamp_streamed_provider(
+                                            data, provider_seen
+                                        )
 
                                         if requested_model:
                                             # Apply requested_model override
@@ -2419,6 +2451,7 @@ class BaseUpstreamProvider:
                             try:
                                 combined_data = {
                                     "model": last_model_seen or "unknown",
+                                    "provider": provider_seen,
                                     "usage": usage_data,
                                 }
                                 cost_data = await adjust_payment_for_tokens(
@@ -4197,6 +4230,7 @@ class BaseUpstreamProvider:
                 },
             )
 
+        provider_seen: str | None = None
         for i, line in enumerate(lines):
             if line.startswith("data: "):
                 try:
@@ -4204,7 +4238,9 @@ class BaseUpstreamProvider:
                     if not isinstance(data_json, dict):
                         continue
                     provider_before = data_json.get("provider")
-                    self._apply_provider_field(data_json)
+                    provider_seen = self._stamp_streamed_provider(
+                        data_json, provider_seen
+                    )
                     changed = data_json.get("provider") != provider_before
                     if cost_data and "usage" in data_json and data_json["usage"]:
                         _inject_cost_into_usage(data_json, cost_data)
@@ -5265,6 +5301,7 @@ class BaseUpstreamProvider:
                 },
             )
 
+        provider_seen: str | None = None
         for i, (fields, data) in enumerate(events):
             if data.strip() == "[DONE]":
                 continue
@@ -5275,7 +5312,7 @@ class BaseUpstreamProvider:
             if not isinstance(data_json, dict):
                 continue
             provider_before = data_json.get("provider")
-            self._apply_provider_field(data_json)
+            provider_seen = self._stamp_streamed_provider(data_json, provider_seen)
             changed = data_json.get("provider") != provider_before
             payload = _responses_usage_payload(data_json)
             if cost_data and isinstance(payload.get("usage"), dict):

routstr/upstream/generic.py

@@ -5,7 +5,7 @@ from urllib.parse import urlparse
 
 import httpx
 
-from .base import BaseUpstreamProvider
+from .base import BaseUpstreamProvider, _reported_provider
 from .model_paths import public_provider_url
 from .pricing_resolver import (
     FallbackPricingResolver,
@@ -60,8 +60,7 @@ class GenericUpstreamProvider(BaseUpstreamProvider):
         """
         if not isinstance(response_json, dict):
             return
-        existing = response_json.get("provider")
-        if not (isinstance(existing, str) and existing.strip()):
+        if _reported_provider(response_json) is None:
             response_json["provider"] = (
                 urlparse(public_provider_url(self.base_url)).hostname
                 or self.upstream_name

routstr/upstream/openrouter.py

@@ -3,7 +3,7 @@ from typing import TYPE_CHECKING
 import httpx
 
 from ..payment.models import Model, async_fetch_openrouter_models
-from .base import BaseUpstreamProvider
+from .base import BaseUpstreamProvider, _reported_provider
 from .model_paths import public_provider_url
 
 if TYPE_CHECKING:
@@ -35,8 +35,7 @@ class OpenRouterUpstreamProvider(BaseUpstreamProvider):
             return
         response_json["provider_url"] = public_provider_url(self.base_url)
         provider_type = (self.provider_type or "").strip()
-        existing = response_json.get("provider")
-        sub = existing.strip() if isinstance(existing, str) else ""
+        sub = _reported_provider(response_json) or ""
         # Strip any already-applied "openrouter:" prefixes (idempotency).
         prefix = f"{provider_type}:"
         while sub.lower().startswith(prefix.lower()):

tests/unit/test_provider_field_injection.py

@@ -89,6 +89,33 @@ def test_apply_provider_field_non_string_upstream_treated_as_missing() -> None:
     assert data["provider"] == "unknown"
 
 
+def test_apply_provider_field_openrouter_reads_nested_envelopes() -> None:
+    """Anthropic ``message`` and Responses ``response`` envelopes nest the
+    upstream provider; it must not be reported as unknown."""
+    p = _make_provider(OpenRouterUpstreamProvider, "openrouter")
+    message_start: dict = {
+        "type": "message_start",
+        "message": {"provider": "Anthropic"},
+    }
+    p._apply_provider_field(message_start)
+    assert message_start["provider"] == "openrouter:Anthropic"
+
+    created: dict = {"type": "response.created", "response": {"provider": "OpenAI"}}
+    p._apply_provider_field(created)
+    assert created["provider"] == "openrouter:OpenAI"
+
+
+def test_stamp_streamed_provider_carries_earlier_provider() -> None:
+    """Events without their own provider inherit the one reported earlier in
+    the stream instead of becoming ``unknown``."""
+    p = _make_provider(OpenRouterUpstreamProvider, "openrouter")
+    first: dict = {"provider": "Fireworks"}
+    carried = p._stamp_streamed_provider(first, None)
+    delta: dict = {"type": "content_block_delta"}
+    assert p._stamp_streamed_provider(delta, carried) == "Fireworks"
+    assert first["provider"] == delta["provider"] == "openrouter:Fireworks"
+
+
 def test_apply_provider_field_idempotent_for_direct_upstream() -> None:
     """Calling twice on a direct upstream payload keeps the same value and
     never nests the prefix (no ``anthropic:anthropic``)."""

tests/unit/test_x_cashu_provider_path.py

@@ -52,3 +52,50 @@ async def test_x_cashu_responses_stream_reports_complete_provider_path() -> None
 
     payload = json.loads((await _body(response)).decode().removeprefix("data: "))
     assert payload["provider"] == "openrouter:z.ai"
+
+
+@pytest.mark.asyncio
+async def test_x_cashu_messages_stream_carries_provider_to_later_events() -> None:
+    provider = OpenRouterUpstreamProvider(api_key="test-key")
+    events = [
+        {"type": "message_start", "message": {"provider": "Anthropic"}},
+        {"type": "content_block_delta", "delta": {"text": "hi"}},
+    ]
+    content = "".join(f"data: {json.dumps(e)}\n" for e in events)
+
+    response = await provider.handle_x_cashu_streaming_response(
+        content,
+        httpx.Response(200, headers={"content-type": "text/event-stream"}),
+        amount=1,
+        unit="sat",
+        max_cost_for_model=1,
+    )
+
+    lines = (await _body(response)).decode().splitlines()
+    stamped = [json.loads(line.removeprefix("data: ")) for line in lines if line]
+    assert [e["provider"] for e in stamped] == ["openrouter:Anthropic"] * 2
+
+
+@pytest.mark.asyncio
+async def test_x_cashu_responses_stream_carries_nested_provider() -> None:
+    provider = OpenRouterUpstreamProvider(api_key="test-key")
+    events = [
+        {"type": "response.created", "response": {"provider": "OpenAI"}},
+        {"type": "response.output_text.delta", "delta": "hi"},
+    ]
+    content = "".join(f"data: {json.dumps(e)}\n\n" for e in events)
+
+    with patch.object(
+        provider, "get_x_cashu_cost", new=AsyncMock(return_value=None)
+    ):
+        response = await provider.handle_x_cashu_streaming_responses_response(
+            content,
+            httpx.Response(200, headers={"content-type": "text/event-stream"}),
+            amount=1,
+            unit="sat",
+            max_cost_for_model=1,
+        )
+
+    lines = (await _body(response)).decode().splitlines()
+    stamped = [json.loads(line.removeprefix("data: ")) for line in lines if line]
+    assert [e["provider"] for e in stamped] == ["openrouter:OpenAI"] * 2