Updates to prompt for tool calls (#29)

* update system prompts to drop new line

* Add tool prompt formats

* support json format

* JSON in caps

* function_tag system prompt is also added as a user message

* added docstrings for ToolPromptFormat

---------

Co-authored-by: Hardik Shah <hjshah@fb.com>

llama_toolchain/agentic_system/api/datatypes.py

@@ -110,6 +110,35 @@ class Session(BaseModel):
     started_at: datetime
 
 
+@json_schema_type
+class ToolPromptFormat(Enum):
+    """This Enum refers to the prompt format for calling zero shot tools
+
+    `json` --
+        Refers to the json format for calling tools.
+        The json format takes the form like
+        {
+            "type": "function",
+            "function" : {
+                "name": "function_name",
+                "description": "function_description",
+                "parameters": {...}
+            }
+        }
+
+    `function_tag` --
+        This is an example of how you could define
+        your own user defined format for making tool calls.
+        The function_tag format looks like this,
+        <function=function_name>(parameters)</function>
+
+    The detailed prompts for each of these formats are defined in `system_prompt.py`
+    """
+
+    json = "json"
+    function_tag = "function_tag"
+
+
 @json_schema_type
 class AgenticSystemInstanceConfig(BaseModel):
     instructions: str
@@ -127,6 +156,9 @@ class AgenticSystemInstanceConfig(BaseModel):
     # if you completely want to replace the messages prefixed by the system,
     # this is debug only
     debug_prefix_messages: Optional[List[Message]] = Field(default_factory=list)
+    tool_prompt_format: Optional[ToolPromptFormat] = Field(
+        default=ToolPromptFormat.json
+    )
 
 
 class AgenticSystemTurnResponseEventType(Enum):