fix(models): skip non-chat models when resolving chat defaults (#6907)

routes/model_routes.py

@@ -659,7 +659,7 @@ _NON_CHAT_CONTAINS = (
     "gliner", "riva", "-parse", "-embedqa", "-nemoretriever",
     "topic-control", "calibration",
     "ai-synthetic-video", "cosmos-reason2",
-    "bge", "llama-guard",
+    "bge", "llama-guard", "-embed", "rerank",
 )
 _NON_CHAT_EXACT_PREFIXES = (
     "gpt-audio",  # gpt-audio, gpt-audio-mini etc. (not gpt-4o-audio-preview which is chat)
@@ -2846,11 +2846,12 @@ def setup_model_routes(model_discovery):
                 return {"endpoint_id": "", "endpoint_url": "", "model": ""}
             base = _normalize_base(ep.base_url)
             chat_url = build_chat_url(base)
+            if model and not _is_chat_model(model):
+                model = ""
             if not model and (getattr(ep, "cached_models", None) or getattr(ep, "pinned_models", None)):
                 try:
                     visible = _visible_models(ep.cached_models, getattr(ep, "hidden_models", None), getattr(ep, "pinned_models", None))
-                    if visible:
-                        model = visible[0]
+                    model = next((mid for mid in visible if _is_chat_model(mid)), "")
                 except Exception:
                     pass
             return {"endpoint_id": ep.id, "endpoint_url": chat_url, "model": model}

tests/test_default_chat_model_filter.py

@@ -0,0 +1,86 @@
+"""Issue #2137: never preselect an embedding or other non-chat model."""
+
+import json
+from types import SimpleNamespace
+
+import pytest
+from fastapi import FastAPI
+from fastapi.testclient import TestClient
+
+from core.database import ModelEndpoint
+from routes import model_routes, prefs_routes
+from tests.helpers.database import disposable_database
+
+
+@pytest.fixture
+def defaults_api(monkeypatch, tmp_path):
+    defaults = {}
+    with disposable_database(tmp_path) as factory:
+        monkeypatch.setattr(model_routes, "SessionLocal", factory)
+        monkeypatch.setattr(model_routes, "_load_settings", lambda: {})
+        monkeypatch.setattr(prefs_routes, "_load_for_user", lambda owner: defaults)
+        app = FastAPI()
+        app.state.auth_manager = SimpleNamespace(is_admin=lambda owner: False)
+
+        @app.middleware("http")
+        async def owner(request, call_next):
+            request.state.current_user = "alice"
+            return await call_next(request)
+
+        app.include_router(model_routes.setup_model_routes(model_discovery=None))
+        with TestClient(app) as client:
+            yield client, factory, defaults
+
+
+def _endpoint(factory, *, cached=(), pinned=(), hidden=(), owner="alice", endpoint_id="ep"):
+    with factory() as db:
+        db.add(ModelEndpoint(
+            id=endpoint_id, name="Fixture", base_url="http://model.invalid/v1", owner=owner,
+            is_enabled=True, cached_models=json.dumps(cached),
+            pinned_models=json.dumps(pinned), hidden_models=json.dumps(hidden),
+        ))
+        db.commit()
+
+
+@pytest.mark.parametrize("non_chat", [
+    "text-embedding-3-small", "nomic-embed-text:latest", "jina-reranker-v2-base",
+    "tts-1", "whisper-1", "gpt-image-1",
+])
+def test_automatic_default_skips_non_chat_models(defaults_api, non_chat):
+    client, factory, _ = defaults_api
+    _endpoint(factory, cached=[non_chat, "chat-model"])
+    assert client.get("/api/default-chat").json()["model"] == "chat-model"
+
+
+def test_non_chat_saved_default_falls_back_to_visible_pinned_chat(defaults_api):
+    client, factory, defaults = defaults_api
+    _endpoint(factory, cached=["text-embedding-3-small", "hidden-chat"],
+              pinned=["jina-reranker-v2-base", "pinned-chat"], hidden=["hidden-chat"])
+    defaults.update(default_endpoint_id="ep", default_model="text-embedding-3-small")
+    assert client.get("/api/default-chat").json()["model"] == "pinned-chat"
+
+
+def test_no_chat_candidate_leaves_model_empty(defaults_api):
+    client, factory, defaults = defaults_api
+    _endpoint(factory, cached=["text-embedding-3-small", "hidden-chat"],
+              pinned=["jina-reranker-v2-base"], hidden=["hidden-chat"])
+    defaults.update(default_endpoint_id="ep", default_model="text-embedding-3-small")
+    result = client.get("/api/default-chat").json()
+    assert result == {"endpoint_id": "ep", "endpoint_url": "http://model.invalid/v1/chat/completions", "model": ""}
+
+
+def test_valid_explicit_model_survives_stale_catalog(defaults_api):
+    client, factory, defaults = defaults_api
+    _endpoint(factory, cached=["text-embedding-3-small", "other-chat"])
+    defaults.update(default_endpoint_id="ep", default_model="my-custom-chat")
+    assert client.get("/api/default-chat").json()["model"] == "my-custom-chat"
+
+
+def test_model_filter_preserves_owner_scope(defaults_api):
+    client, factory, defaults = defaults_api
+    _endpoint(factory, owner="bob", endpoint_id="bobs-endpoint", cached=["bobs-chat"])
+    _endpoint(factory, cached=["text-embedding-3-small", "alices-chat"])
+    defaults.update(default_endpoint_id="bobs-endpoint")
+    result = client.get("/api/default-chat").json()
+    assert result["endpoint_id"] == "ep"
+    assert result["model"] == "alices-chat"