[Feature] UI - Models: allow empty api_key for Anthropic provider (BYOK)

litellm/proxy/public_endpoints/provider_create_fields.json

@@ -218,8 +218,8 @@
         "key": "api_key",
         "label": "API Key",
         "placeholder": "sk-",
-        "tooltip": null,
-        "required": true,
+        "tooltip": "Leave empty for BYOK (bring-your-own-key) flows, where clients forward their own Anthropic key via the x-api-key header. Requires the 'Forward LLM provider auth headers' UI setting to be enabled.",
+        "required": false,
         "field_type": "password",
         "options": null,
         "default_value": null

tests/test_litellm/proxy/public_endpoints/test_public_endpoints.py

@@ -138,6 +138,34 @@ def test_azure_provider_fields_include_entra_id():
     assert fields_by_key["client_secret"]["required"] is False
 
 
+def test_anthropic_provider_fields_support_byok():
+    """
+    The Anthropic provider form must allow BYOK:
+    - api_key is optional (not required) so admins can create models without a key
+    - api_key has a non-null tooltip explaining the BYOK use case
+    """
+    app_instance = FastAPI()
+    app_instance.include_router(router)
+    test_client = TestClient(app_instance)
+
+    response = test_client.get("/public/providers/fields")
+    assert response.status_code == 200
+    providers = response.json()
+
+    anthropic = next((p for p in providers if p["provider"] == "Anthropic"), None)
+    assert anthropic is not None, "Anthropic provider entry not found"
+
+    fields_by_key = {f["key"]: f for f in anthropic["credential_fields"]}
+    assert "api_key" in fields_by_key
+    assert fields_by_key["api_key"]["required"] is False, (
+        "Anthropic api_key must be optional so admins can configure BYOK models "
+        "without entering a key. See BYOK tutorial."
+    )
+    assert fields_by_key["api_key"].get("tooltip"), (
+        "Anthropic api_key must have a tooltip explaining the BYOK use case."
+    )
+
+
 def test_public_model_hub_with_healthy_model():
     """Test that health information is populated for a healthy model"""
     app = FastAPI()