Refactor tool call processing and add provider mapping

Author: wongjingping

defog/llm/models.py

@@ -3,6 +3,13 @@
 from typing import Optional, Union, Dict, Any, Literal
 
 
+class Provider(Enum):
+    ANTHROPIC = "anthropic"
+    OPENAI = "openai"
+    GEMINI = "gemini"
+    TOGETHER = "together"
+
+
 class OpenAIFunctionSpecs(BaseModel):
     name: str  # name of the function to call
     description: Optional[str] = None  # description of the function