fix(orcarouter_models): set User-Agent on remote model fetch

app/orcarouter_models.py

@@ -149,8 +149,16 @@ async def _fetch_remote(url: str, timeout: float = _FETCH_TIMEOUT_SECONDS) -> li
     would silently flip the unreachable tile to the static fallback for
     a full TTL.
     """
+    from app.cli import _version
+
     async with httpx.AsyncClient(timeout=timeout, follow_redirects=True) as c:
-        r = await c.get(url, headers={"Accept": "application/json"})
+        r = await c.get(
+            url,
+            headers={
+                "Accept": "application/json",
+                "User-Agent": f"orcarouter-lite/{_version()}",
+            },
+        )
         r.raise_for_status()
         return _parse_response(r.headers.get("Content-Type", ""), r.text)
 

tests/unit/test_orcarouter_models_fetch.py

@@ -0,0 +1,71 @@
+"""Verify _fetch_remote sends a User-Agent header.
+
+Many CDNs and WAFs (Cloudflare, AWS CloudFront default rules) block
+requests without a User-Agent. The unreachable-models tile silently
+degrades to the static fallback for a full TTL when the remote is
+blocked, making it look like the remote is down when it is actually
+rejecting our requests.
+
+The conftest autouse fixture replaces ``orcarouter_models._fetch_remote``
+with a network-isolated stub. We hold a direct reference to the real
+function (imported before the fixture runs) so our httpx mock is
+actually exercised.
+"""
+
+from __future__ import annotations
+
+import json
+
+import httpx
+import pytest
+
+from app.orcarouter_models import _fetch_remote as _real_fetch_remote
+
+
+class _FakeResponse:
+    status_code = 200
+    headers = {"Content-Type": "application/json"}
+    text = json.dumps({"data": [{"id": "gpt-4o"}]})
+
+    def raise_for_status(self):
+        pass
+
+
+def _make_fake_client(captured: dict):
+    class FakeClient:
+        def __init__(self, **kwargs):
+            pass
+
+        async def __aenter__(self):
+            return self
+
+        async def __aexit__(self, *args):
+            pass
+
+        async def get(self, url, headers=None):
+            captured.update(headers or {})
+            return _FakeResponse()
+
+    return FakeClient
+
+
+@pytest.mark.asyncio
+async def test_fetch_remote_sends_user_agent(monkeypatch):
+    captured: dict[str, str] = {}
+    monkeypatch.setattr(httpx, "AsyncClient", _make_fake_client(captured))
+
+    ids = await _real_fetch_remote("https://example.com/models")
+
+    assert "User-Agent" in captured
+    assert captured["User-Agent"].startswith("orcarouter-lite/")
+    assert ids == ["gpt-4o"]
+
+
+@pytest.mark.asyncio
+async def test_fetch_remote_accept_header_present(monkeypatch):
+    captured: dict[str, str] = {}
+    monkeypatch.setattr(httpx, "AsyncClient", _make_fake_client(captured))
+
+    await _real_fetch_remote("https://example.com/models")
+
+    assert captured.get("Accept") == "application/json"