diff --git a/src/llm/base.py b/src/llm/base.py
new file mode 100644
index 0000000..1ab5910
--- /dev/null
+++ b/src/llm/base.py
@@ -0,0 +1,28 @@
+"""Base LLM client interface."""
+
+from abc import ABC, abstractmethod
+from collections.abc import Iterator
+
+
+class LLMClient(ABC):
+    """Abstract base class for LLM clients."""
+
+    @abstractmethod
+    def generate(self, prompt: str, **kwargs) -> str:
+        """Generate a response from the LLM."""
+        pass
+
+    @abstractmethod
+    def stream_generate(self, prompt: str, **kwargs) -> Iterator[str]:
+        """Stream a response from the LLM."""
+        pass
+
+    @abstractmethod
+    def test_connection(self) -> bool:
+        """Test if the LLM service is available."""
+        pass
+
+    @abstractmethod
+    def get_available_models(self) -> list[str]:
+        """Get list of available models."""
+        pass