convert tools to openai (#6100)

langchain/tools/__init__.py

@@ -9,6 +9,7 @@ from langchain.tools.azure_cognitive_services import (
 from langchain.tools.base import BaseTool, StructuredTool, Tool, tool
 from langchain.tools.bing_search.tool import BingSearchResults, BingSearchRun
 from langchain.tools.brave_search.tool import BraveSearch
+from langchain.tools.convert_to_openai import format_tool_to_openai_function
 from langchain.tools.ddg_search.tool import DuckDuckGoSearchResults, DuckDuckGoSearchRun
 from langchain.tools.file_management.copy import CopyFileTool
 from langchain.tools.file_management.delete import DeleteFileTool
@@ -122,4 +123,5 @@ __all__ = [
     "YouTubeSearchTool",
     "BraveSearch",
     "PubmedQueryRun",
+    "format_tool_to_openai_function",
 ]

langchain/tools/convert_to_openai.py

@@ -0,0 +1,53 @@
+from typing import TypedDict
+
+from langchain.tools import BaseTool, StructuredTool
+
+
+class FunctionDescription(TypedDict):
+    """Representation of a callable function to the OpenAI API."""
+
+    name: str
+    """The name of the function."""
+    description: str
+    """A description of the function."""
+    parameters: dict
+    """The parameters of the function."""
+
+
+def format_tool_to_openai_function(tool: BaseTool) -> FunctionDescription:
+    """Format tool into the open AI function API."""
+    if isinstance(tool, StructuredTool):
+        schema_ = tool.args_schema.schema()
+        # Bug with required missing for structured tools.
+        required = sorted(schema_["properties"])  # BUG WORKAROUND
+        return {
+            "name": tool.name,
+            "description": tool.description,
+            "parameters": {
+                "type": "object",
+                "properties": schema_["properties"],
+                "required": required,
+            },
+        }
+    else:
+        if tool.args_schema:
+            parameters = tool.args_schema.schema()
+        else:
+            parameters = {
+                # This is a hack to get around the fact that some tools
+                # do not expose an args_schema, and expect an argument
+                # which is a string.
+                # And Open AI does not support an array type for the
+                # parameters.
+                "properties": {
+                    "__arg1": {"title": "__arg1", "type": "string"},
+                },
+                "required": ["__arg1"],
+                "type": "object",
+            }
+
+        return {
+            "name": tool.name,
+            "description": tool.description,
+            "parameters": parameters,
+        }

tests/unit_tests/tools/test_public_api.py

@@ -62,6 +62,7 @@ _EXPECTED = [
     "YouTubeSearchTool",
     "BraveSearch",
     "PubmedQueryRun",
+    "format_tool_to_openai_function",
 ]