Make Tools own model, add ToolKit Concept (#1095)

Follow-up of @hinthornw's PR:

- Migrate the Tool abstraction to a separate file (`BaseTool`).
- `Tool` implementation of `BaseTool` takes in function and coroutine to
more easily maintain backwards compatibility
- Add a Toolkit abstraction that can own the generation of tools around
a shared concept or state

---------

Co-authored-by: William FH <13333726+hinthornw@users.noreply.github.com>
Co-authored-by: Harrison Chase <hw.chase.17@gmail.com>
Co-authored-by: Francisco Ingham <fpingham@gmail.com>
Co-authored-by: Dhruv Anand <105786647+dhruv-anand-aintech@users.noreply.github.com>
Co-authored-by: cragwolfe <cragcw@gmail.com>
Co-authored-by: Anton Troynikov <atroyn@users.noreply.github.com>
Co-authored-by: Oliver Klingefjord <oliver@klingefjord.com>
Co-authored-by: William Fu-Hinthorn <whinthorn@Williams-MBP-3.attlocal.net>
Co-authored-by: Bruno Bornsztein <bruno.bornsztein@gmail.com>

tests/unit_tests/agents/test_agent.py

@@ -4,7 +4,8 @@ from typing import Any, List, Mapping, Optional
 
 from pydantic import BaseModel
 
-from langchain.agents import AgentExecutor, Tool, initialize_agent
+from langchain.agents import AgentExecutor, initialize_agent
+from langchain.agents.tools import Tool
 from langchain.callbacks.base import CallbackManager
 from langchain.llms.base import LLM
 from tests.unit_tests.callbacks.fake_callback_handler import FakeCallbackHandler
@@ -42,8 +43,16 @@ def _get_agent(**kwargs: Any) -> AgentExecutor:
     ]
     fake_llm = FakeListLLM(responses=responses)
     tools = [
-        Tool("Search", lambda x: x, "Useful for searching"),
-        Tool("Lookup", lambda x: x, "Useful for looking up things in a table"),
+        Tool(
+            name="Search",
+            func=lambda x: x,
+            description="Useful for searching",
+        ),
+        Tool(
+            name="Lookup",
+            func=lambda x: x,
+            description="Useful for looking up things in a table",
+        ),
     ]
     agent = initialize_agent(
         tools, fake_llm, agent="zero-shot-react-description", verbose=True, **kwargs
@@ -79,7 +88,12 @@ def test_agent_with_callbacks_global() -> None:
     ]
     fake_llm = FakeListLLM(responses=responses, callback_manager=manager, verbose=True)
     tools = [
-        Tool("Search", lambda x: x, "Useful for searching"),
+        Tool(
+            name="Search",
+            func=lambda x: x,
+            description="Useful for searching",
+            callback_manager=manager,
+        ),
     ]
     agent = initialize_agent(
         tools,
@@ -118,7 +132,12 @@ def test_agent_with_callbacks_local() -> None:
     ]
     fake_llm = FakeListLLM(responses=responses, callback_manager=manager, verbose=True)
     tools = [
-        Tool("Search", lambda x: x, "Useful for searching"),
+        Tool(
+            name="Search",
+            func=lambda x: x,
+            description="Useful for searching",
+            callback_manager=manager,
+        ),
     ]
     agent = initialize_agent(
         tools,
@@ -159,7 +178,11 @@ def test_agent_with_callbacks_not_verbose() -> None:
     ]
     fake_llm = FakeListLLM(responses=responses, callback_manager=manager)
     tools = [
-        Tool("Search", lambda x: x, "Useful for searching"),
+        Tool(
+            name="Search",
+            func=lambda x: x,
+            description="Useful for searching",
+        ),
     ]
     agent = initialize_agent(
         tools,
@@ -186,7 +209,12 @@ def test_agent_tool_return_direct() -> None:
     ]
     fake_llm = FakeListLLM(responses=responses)
     tools = [
-        Tool("Search", lambda x: x, "Useful for searching", return_direct=True),
+        Tool(
+            name="Search",
+            func=lambda x: x,
+            description="Useful for searching",
+            return_direct=True,
+        ),
     ]
     agent = initialize_agent(
         tools,
@@ -204,7 +232,12 @@ def test_agent_with_new_prefix_suffix() -> None:
         responses=["FooBarBaz\nAction: Search\nAction Input: misalignment"]
     )
     tools = [
-        Tool("Search", lambda x: x, "Useful for searching", return_direct=True),
+        Tool(
+            name="Search",
+            func=lambda x: x,
+            description="Useful for searching",
+            return_direct=True,
+        ),
     ]
     prefix = "FooBarBaz"
 

tests/unit_tests/agents/test_react.py

@@ -58,8 +58,8 @@ def test_predict_until_observation_normal() -> None:
     outputs = ["foo\nAction 1: Search[foo]"]
     fake_llm = FakeListLLM(responses=outputs)
     tools = [
-        Tool("Search", lambda x: x),
-        Tool("Lookup", lambda x: x),
+        Tool(name="Search", func=lambda x: x, description="foo"),
+        Tool(name="Lookup", func=lambda x: x, description="bar"),
     ]
     agent = ReActDocstoreAgent.from_llm_and_tools(fake_llm, tools)
     output = agent.plan([], input="")
@@ -72,8 +72,8 @@ def test_predict_until_observation_repeat() -> None:
     outputs = ["foo", " Search[foo]"]
     fake_llm = FakeListLLM(responses=outputs)
     tools = [
-        Tool("Search", lambda x: x),
-        Tool("Lookup", lambda x: x),
+        Tool(name="Search", func=lambda x: x, description="foo"),
+        Tool(name="Lookup", func=lambda x: x, description="bar"),
     ]
     agent = ReActDocstoreAgent.from_llm_and_tools(fake_llm, tools)
     output = agent.plan([], input="")

tests/unit_tests/agents/test_tools.py

@@ -2,6 +2,7 @@
 import pytest
 
 from langchain.agents.tools import Tool, tool
+from langchain.schema import AgentAction
 
 
 def test_unnamed_decorator() -> None:
@@ -65,3 +66,42 @@ def test_missing_docstring() -> None:
         @tool
         def search_api(query: str) -> str:
             return "API result"
+
+
+def test_create_tool_posistional_args() -> None:
+    """Test that positional arguments are allowed."""
+    test_tool = Tool("test_name", lambda x: x, "test_description")
+    assert test_tool("foo") == "foo"
+    assert test_tool.name == "test_name"
+    assert test_tool.description == "test_description"
+
+
+def test_create_tool_keyword_args() -> None:
+    """Test that keyword arguments are allowed."""
+    test_tool = Tool(name="test_name", func=lambda x: x, description="test_description")
+    assert test_tool("foo") == "foo"
+    assert test_tool.name == "test_name"
+    assert test_tool.description == "test_description"
+
+
+@pytest.mark.asyncio
+async def test_create_async_tool() -> None:
+    """Test that async tools are allowed."""
+
+    async def _test_func(x: str) -> str:
+        return x
+
+    test_tool = Tool(
+        name="test_name",
+        func=lambda x: x,
+        description="test_description",
+        coroutine=_test_func,
+    )
+    assert test_tool("foo") == "foo"
+    assert test_tool.name == "test_name"
+    assert test_tool.description == "test_description"
+    assert test_tool.coroutine is not None
+    assert (
+        await test_tool.arun(AgentAction(tool_input="foo", tool="test_name", log=""))
+        == "foo"
+    )