fix(guardrails): declare api_base/api_key on GenericGuardrailAPIConfigModel

The dashboard renders a provider's configuration form from the fields its
config model declares (GET /guardrails/ui/provider_specific_params). For
generic_guardrail_api that model only declared optional_params, and the form
deliberately skips a nested optional_params block, so selecting the provider
rendered no configuration fields at all - not even the api_base the endpoint
cannot work without.

api_base and api_key are read from litellm_params at runtime, so they never
needed to be model fields to work from config.yaml; they do need to be fields
for the UI to offer them. Six other providers (compresr, headroom,
crowdstrike_aidr, alice, aporia_ai, cato_networks) already declare them this
way, so this makes the generic provider consistent rather than inventing a
mechanism.

Fixes #34927

litellm/types/proxy/guardrails/guardrail_hooks/generic_guardrail_api.py

@@ -130,6 +130,14 @@ class GenericGuardrailAPIConfigModel(
 ):
     """Configuration parameters for the Generic Guardrail API guardrail"""
 
+    api_base: str | None = Field(
+        default=None,
+        description="Base URL of the guardrail endpoint to call (e.g. http://llm-guard:8000/analyze). Required when creating the guardrail: without it there is nowhere to send the request.",
+    )
+    api_key: str | None = Field(
+        default=None,
+        description="API key sent to the guardrail endpoint. Optional; omit it when the endpoint does not authenticate the caller.",
+    )
     optional_params: GenericGuardrailAPIOptionalParams | None = Field(
         default_factory=GenericGuardrailAPIOptionalParams,
         description="Optional parameters for the Generic Guardrail API guardrail",

tests/unit/proxy/guardrails/guardrail_hooks/test_generic_guardrail_api.py

@@ -1545,6 +1545,26 @@ class TestGenericGuardrailAPIStreamingConfig:
 
         assert GenericGuardrailAPI.get_config_model() is GenericGuardrailAPIConfigModel
 
+    def test_config_model_declares_connection_fields(self):
+        """The dashboard builds a provider's form from this model.
+
+        ``get_provider_specific_params`` renders whatever the config model
+        declares, and the form only offers those keys, so ``api_base`` and
+        ``api_key`` have to be fields here even though the initializer reads
+        them off ``litellm_params`` at runtime. Without them the provider shows
+        no configuration fields at all (BerriAI/litellm#34927).
+        """
+        from litellm.types.proxy.guardrails.guardrail_hooks.generic_guardrail_api import (
+            GenericGuardrailAPIConfigModel,
+        )
+
+        fields = GenericGuardrailAPIConfigModel.model_json_schema().get("properties", {})
+
+        for field_name in ("api_base", "api_key"):
+            assert field_name in fields, f"{field_name} must be a config model field"
+            assert fields[field_name].get("description"), f"{field_name} needs a description for the form"
+            assert field_name not in GenericGuardrailAPIConfigModel.model_json_schema().get("required", [])
+
     def test_streaming_transform_mode_defaults_block_only(self):
         guardrail = GenericGuardrailAPI(
             api_base="https://api.test.guardrail.com",