feat: add parsing for Literal types (#1872)

letta/functions/functions.py

@@ -2,7 +2,7 @@ import importlib
 import inspect
 from textwrap import dedent  # remove indentation
 from types import ModuleType
-from typing import Dict, List, Optional
+from typing import Dict, List, Literal, Optional
 
 from letta.errors import LettaToolCreateError
 from letta.functions.schema_generator import generate_schema
@@ -20,6 +20,7 @@ def derive_openai_json_schema(source_code: str, name: Optional[str] = None) -> d
             "Optional": Optional,
             "List": List,
             "Dict": Dict,
+            "Literal": Literal,
             # To support Pydantic models
             # "BaseModel": BaseModel,
             # "Field": Field,

letta/functions/schema_generator.py

@@ -5,6 +5,7 @@ from typing import Any, Dict, List, Optional, Type, Union, get_args, get_origin
 from composio.client.collections import ActionParametersModel
 from docstring_parser import parse
 from pydantic import BaseModel
+from typing_extensions import Literal
 
 from letta.functions.mcp_client.types import MCPTool
 
@@ -70,6 +71,10 @@ def type_to_json_schema_type(py_type) -> dict:
             "items": type_to_json_schema_type(args[0]),
         }
 
+    # Handle literals
+    if get_origin(py_type) is Literal:
+        return {"type": "string", "enum": get_args(py_type)}
+
     # Handle object types
     if py_type == dict or origin in (dict, Dict):
         args = get_args(py_type)