fix(api): fall back to factory max_tokens for tenant models (#16364)

api/db/joint_services/tenant_model_service.py

@@ -45,6 +45,19 @@ def _factory_model_types(llm: dict) -> list[str]:
     return [model_type] if model_type else []
 
 
+def _lookup_factory_llm_info(provider_name: str, pure_model_name: str, extra_fields: dict) -> dict | None:
+    region = extra_fields.get("region", "default")
+    if region == "intl" and provider_name.lower() == "siliconflow":
+        target_factory_name = "siliconflow_intl"
+    else:
+        target_factory_name = provider_name
+    fac_list = [f for f in settings.FACTORY_LLM_INFOS if f["name"] == target_factory_name]
+    if not fac_list:
+        return None
+    llm_list = [llm for llm in fac_list[0]["llm"] if llm["llm_name"] == pure_model_name]
+    return llm_list[0] if llm_list else None
+
+
 def _decode_api_key_config(raw_api_key: str) -> tuple[str, bool | None, str | None]:
     if not raw_api_key:
         return raw_api_key, None, None
@@ -249,6 +262,11 @@ def get_model_config_from_provider_instance(tenant_id, model_type: str | enum.En
             raise LookupError(f"Model {model_name} cannot be used as {model_type_val} model.")
 
         model_extra = json.loads(model_obj.extra) if model_obj.extra else {}
+        llm_info = _lookup_factory_llm_info(provider_obj.provider_name, pure_model_name, extra_fields)
+        if "max_tokens" in model_extra:
+            max_tokens = model_extra["max_tokens"]
+        else:
+            max_tokens = (llm_info or {}).get("max_tokens", 8192)
         model_config = {
             "llm_factory": provider_obj.provider_name,
             "api_key": api_key,
@@ -256,7 +274,7 @@ def get_model_config_from_provider_instance(tenant_id, model_type: str | enum.En
             "api_base": extra_fields.get("base_url", ""),
             "model_type": model_obj.model_type,
             "is_tools": model_extra.get("is_tools", is_tool),
-            "max_tokens": model_extra.get("max_tokens") or 8192,
+            "max_tokens": max_tokens,
         }
         if provider_name.lower() == "somark":
             # SoMark/OCR factories read parser config (somark_*, parse_method, ...)

test/unit_test/api/db/joint_services/test_tenant_model_service_max_tokens.py

@@ -0,0 +1,122 @@
+#
+#  Copyright 2026 The InfiniFlow Authors. All Rights Reserved.
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+#
+
+from types import SimpleNamespace
+
+import pytest
+
+from common.constants import ActiveStatusEnum
+from api.db.joint_services import tenant_model_service as tms
+
+
+@pytest.mark.p1
+def test_max_tokens_falls_back_to_factory_when_model_extra_empty(monkeypatch):
+    provider = SimpleNamespace(id="provider-1", provider_name="OpenAI")
+    instance = SimpleNamespace(id="instance-1", api_key="sk-test", extra='{"base_url": "https://api.example"}')
+    model = SimpleNamespace(
+        model_name="gpt-test",
+        model_type="chat",
+        status=ActiveStatusEnum.ACTIVE.value,
+        extra="{}",
+    )
+
+    monkeypatch.setattr(
+        tms.TenantModelProviderService,
+        "get_by_tenant_id_and_provider_name",
+        lambda tenant_id, provider_name: provider,
+    )
+    monkeypatch.setattr(
+        tms.TenantModelInstanceService,
+        "get_by_provider_id_and_instance_name",
+        lambda provider_id, instance_name: instance,
+    )
+    monkeypatch.setattr(
+        tms.TenantModelService,
+        "get_by_provider_id_and_instance_id_and_model_type_and_model_name",
+        lambda provider_id, instance_id, model_type, model_name: model,
+    )
+    monkeypatch.setattr(
+        tms.settings,
+        "FACTORY_LLM_INFOS",
+        [
+            {
+                "name": "OpenAI",
+                "llm": [
+                    {
+                        "llm_name": "gpt-test",
+                        "model_type": "chat",
+                        "max_tokens": 128000,
+                    }
+                ],
+            }
+        ],
+    )
+
+    config = tms.get_model_config_from_provider_instance(
+        "tenant-1", "chat", "gpt-test@default@OpenAI"
+    )
+
+    assert config["max_tokens"] == 128000
+
+
+@pytest.mark.p1
+def test_max_tokens_prefers_model_extra_over_factory(monkeypatch):
+    provider = SimpleNamespace(id="provider-1", provider_name="OpenAI")
+    instance = SimpleNamespace(id="instance-1", api_key="sk-test", extra="{}")
+    model = SimpleNamespace(
+        model_name="gpt-test",
+        model_type="chat",
+        status=ActiveStatusEnum.ACTIVE.value,
+        extra='{"max_tokens": 32000}',
+    )
+
+    monkeypatch.setattr(
+        tms.TenantModelProviderService,
+        "get_by_tenant_id_and_provider_name",
+        lambda tenant_id, provider_name: provider,
+    )
+    monkeypatch.setattr(
+        tms.TenantModelInstanceService,
+        "get_by_provider_id_and_instance_name",
+        lambda provider_id, instance_name: instance,
+    )
+    monkeypatch.setattr(
+        tms.TenantModelService,
+        "get_by_provider_id_and_instance_id_and_model_type_and_model_name",
+        lambda provider_id, instance_id, model_type, model_name: model,
+    )
+    monkeypatch.setattr(
+        tms.settings,
+        "FACTORY_LLM_INFOS",
+        [
+            {
+                "name": "OpenAI",
+                "llm": [
+                    {
+                        "llm_name": "gpt-test",
+                        "model_type": "chat",
+                        "max_tokens": 128000,
+                    }
+                ],
+            }
+        ],
+    )
+
+    config = tms.get_model_config_from_provider_instance(
+        "tenant-1", "chat", "gpt-test@default@OpenAI"
+    )
+
+    assert config["max_tokens"] == 32000