diff --git a/litellm/llms/openai_like/dynamic_config.py b/litellm/llms/openai_like/dynamic_config.py
index d7aafe9f06e..efe4bd5340d 100644
--- a/litellm/llms/openai_like/dynamic_config.py
+++ b/litellm/llms/openai_like/dynamic_config.py
@@ -79,6 +79,17 @@ def create_config_class(provider: SimpleProviderConfig):
             # Resolve API key
             resolved_key: Final = api_key or get_secret_str(provider.api_key_env)
 
+            if provider.special_handling.get("require_api_key") and not resolved_key:
+                # Fail closed: without this the caller's OPENAI_API_KEY would be used as a fallback
+                # further down the dispatch path and sent to this provider.
+                from litellm.exceptions import AuthenticationError
+
+                raise AuthenticationError(
+                    message=f"{provider.slug}: no API key. Pass api_key or set {provider.api_key_env}.",
+                    llm_provider=provider.slug,
+                    model="",
+                )
+
             return resolved_base, resolved_key
 
         def get_openai_compatible_provider_info(
diff --git a/litellm/llms/openai_like/providers.json b/litellm/llms/openai_like/providers.json
index 3f978c4fc6c..83bb5cbe30a 100644
--- a/litellm/llms/openai_like/providers.json
+++ b/litellm/llms/openai_like/providers.json
@@ -308,6 +308,9 @@
     "api_key_env": "SAGG_API_KEY",
     "param_mappings": {
       "max_completion_tokens": "max_tokens"
+    },
+    "special_handling": {
+      "require_api_key": true
     }
   }
 }
diff --git a/tests/unit/llms/openai_like/test_sagg_provider.py b/tests/unit/llms/openai_like/test_sagg_provider.py
index da76601da56..ddbae47cc58 100644
--- a/tests/unit/llms/openai_like/test_sagg_provider.py
+++ b/tests/unit/llms/openai_like/test_sagg_provider.py
@@ -38,7 +38,7 @@ class TestSaggProviderConfig:
             model="sagg/deepseek-ai/DeepSeek-V4-Flash-0731",
             custom_llm_provider=None,
             api_base=None,
-            api_key=None,
+            api_key="test-key",
         )
 
         assert model == "deepseek-ai/DeepSeek-V4-Flash-0731"
@@ -84,3 +84,25 @@ class TestSaggProviderConfig:
         assert result["max_tokens"] == 100
         assert "max_completion_tokens" not in result
         assert result["temperature"] == 0.7
+
+
+class TestSaggRequiresItsOwnKey:
+    def _config(self):
+        from litellm.llms.openai_like.dynamic_config import create_config_class
+        from litellm.llms.openai_like.json_loader import JSONProviderRegistry
+
+        return create_config_class(JSONProviderRegistry.get("sagg"))()
+
+    def test_missing_key_fails_closed_even_with_openai_key_set(self, monkeypatch):
+        import pytest
+
+        monkeypatch.delenv("SAGG_API_KEY", raising=False)
+        monkeypatch.setenv("OPENAI_API_KEY", "sk-not-for-sagg")
+        with pytest.raises(litellm.AuthenticationError):
+            self._config()._get_openai_compatible_provider_info(None, None)
+
+    def test_explicit_key_and_env_key_still_work(self, monkeypatch):
+        monkeypatch.delenv("SAGG_API_KEY", raising=False)
+        assert self._config()._get_openai_compatible_provider_info(None, "k1")[1] == "k1"
+        monkeypatch.setenv("SAGG_API_KEY", "k2")
+        assert self._config()._get_openai_compatible_provider_info(None, None)[1] == "k2"