make tools editable (#445)

use dataclass instead of namedtuple, which makes it editable

add example in notebook

docs/examples/agents/custom_tools.ipynb

@@ -23,7 +23,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 2,
+   "execution_count": 1,
    "id": "1aaba18c",
    "metadata": {},
    "outputs": [],
@@ -44,7 +44,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 4,
+   "execution_count": 2,
    "id": "36ed392e",
    "metadata": {},
    "outputs": [],
@@ -52,9 +52,18 @@
     "llm = OpenAI(temperature=0)"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "id": "f8bc72c2",
+   "metadata": {},
+   "source": [
+    "## Completely New Tools\n",
+    "First, we show how to create completely new tools from scratch."
+   ]
+  },
   {
    "cell_type": "code",
-   "execution_count": 5,
+   "execution_count": 3,
    "id": "56ff7670",
    "metadata": {},
    "outputs": [],
@@ -78,7 +87,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 6,
+   "execution_count": 4,
    "id": "5b93047d",
    "metadata": {},
    "outputs": [],
@@ -91,7 +100,7 @@
   },
   {
    "cell_type": "code",
-   "execution_count": 7,
+   "execution_count": 5,
    "id": "6f96a891",
    "metadata": {},
    "outputs": [
@@ -105,41 +114,133 @@
       "\u001b[32;1m\u001b[1;3m I need to find out who Olivia Wilde's boyfriend is and then calculate his age raised to the 0.23 power.\n",
       "Action: Search\n",
       "Action Input: Olivia Wilde's boyfriend\u001b[0m\n",
-      "Observation: \u001b[36;1m\u001b[1;3mOlivia Wilde started dating Harry Styles after ending her years-long engagement to Jason Sudeikis — see their relationship timeline.\u001b[0m\n",
-      "Thought:\u001b[32;1m\u001b[1;3m I need to find out Harry Styles' age.\n",
-      "Action: Search\n",
-      "Action Input: Harry Styles age\u001b[0m\n",
-      "Observation: \u001b[36;1m\u001b[1;3m28 years\u001b[0m\n",
-      "Thought:\u001b[32;1m\u001b[1;3m I need to calculate 28 raised to the 0.23 power.\n",
+      "Observation: \u001b[36;1m\u001b[1;3mHarry Styles\u001b[0m\n",
+      "Thought:\u001b[32;1m\u001b[1;3m I need to calculate Harry Styles' age raised to the 0.23 power.\n",
       "Action: Calculator\n",
-      "Action Input: 28^0.23\u001b[0m\n",
+      "Action Input: 23^0.23\u001b[0m\n",
       "\n",
       "\u001b[1m> Entering new LLMMathChain chain...\u001b[0m\n",
-      "28^0.23\u001b[32;1m\u001b[1;3m\n",
+      "23^0.23\u001b[32;1m\u001b[1;3m\n",
       "\n",
       "```python\n",
       "import math\n",
-      "print(math.pow(28, 0.23))\n",
+      "print(math.pow(23, 0.23))\n",
       "```\n",
       "\u001b[0m\n",
-      "Answer: \u001b[33;1m\u001b[1;3m2.1520202182226886\n",
+      "Answer: \u001b[33;1m\u001b[1;3m2.0568252837687546\n",
       "\u001b[0m\n",
       "\u001b[1m> Finished LLMMathChain chain.\u001b[0m\n",
       "\n",
-      "Observation: \u001b[33;1m\u001b[1;3mAnswer: 2.1520202182226886\n",
+      "Observation: \u001b[33;1m\u001b[1;3mAnswer: 2.0568252837687546\n",
       "\u001b[0m\n",
       "Thought:\u001b[32;1m\u001b[1;3m I now know the final answer.\n",
-      "Final Answer: Harry Styles, Olivia Wilde's boyfriend, is 28 years old and his age raised to the 0.23 power is 2.1520202182226886.\u001b[0m\n",
+      "Final Answer: Harry Styles' age raised to the 0.23 power is 2.0568252837687546.\u001b[0m\n",
       "\u001b[1m> Finished AgentExecutor chain.\u001b[0m\n"
      ]
     },
     {
      "data": {
       "text/plain": [
-       "\"Harry Styles, Olivia Wilde's boyfriend, is 28 years old and his age raised to the 0.23 power is 2.1520202182226886.\""
+       "\"Harry Styles' age raised to the 0.23 power is 2.0568252837687546.\""
       ]
      },
-     "execution_count": 7,
+     "execution_count": 5,
+     "metadata": {},
+     "output_type": "execute_result"
+    }
+   ],
+   "source": [
+    "agent.run(\"Who is Olivia Wilde's boyfriend? What is his current age raised to the 0.23 power?\")"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "1d0430d6",
+   "metadata": {},
+   "source": [
+    "## Modify existing tools\n",
+    "\n",
+    "Now, we show how to load existing tools and just modify them. In the example below, we do something really simple and change the Search tool to have the name `Google Search`."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 22,
+   "id": "79213f40",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "from langchain.agents import load_tools"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 18,
+   "id": "e1067dcb",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "tools = load_tools([\"serpapi\", \"llm-math\"], llm=llm)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 19,
+   "id": "6c66ffe8",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "tools[0].name = \"Google Search\""
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 20,
+   "id": "f45b5bc3",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "agent = initialize_agent(tools, llm, agent=\"zero-shot-react-description\", verbose=True)"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": 21,
+   "id": "565e2b9b",
+   "metadata": {},
+   "outputs": [
+    {
+     "name": "stdout",
+     "output_type": "stream",
+     "text": [
+      "\n",
+      "\n",
+      "\u001b[1m> Entering new AgentExecutor chain...\u001b[0m\n",
+      "\u001b[32;1m\u001b[1;3m I need to find out who Olivia Wilde's boyfriend is and then calculate his age raised to the 0.23 power.\n",
+      "Action: Google Search\n",
+      "Action Input: \"Olivia Wilde boyfriend\"\u001b[0m\n",
+      "Observation: \u001b[36;1m\u001b[1;3mHarry Styles\u001b[0m\n",
+      "Thought:\u001b[32;1m\u001b[1;3m I need to find out Harry Styles' age\n",
+      "Action: Google Search\n",
+      "Action Input: \"Harry Styles age\"\u001b[0m\n",
+      "Observation: \u001b[36;1m\u001b[1;3m28 years\u001b[0m\n",
+      "Thought:\u001b[32;1m\u001b[1;3m I need to calculate 28 raised to the 0.23 power\n",
+      "Action: Calculator\n",
+      "Action Input: 28^0.23\u001b[0m\n",
+      "Observation: \u001b[33;1m\u001b[1;3mAnswer: 2.1520202182226886\n",
+      "\u001b[0m\n",
+      "Thought:\u001b[32;1m\u001b[1;3m I now know the final answer\n",
+      "Final Answer: Harry Styles is Olivia Wilde's boyfriend and his current age raised to the 0.23 power is 2.1520202182226886.\u001b[0m\n",
+      "\u001b[1m> Finished AgentExecutor chain.\u001b[0m\n"
+     ]
+    },
+    {
+     "data": {
+      "text/plain": [
+       "\"Harry Styles is Olivia Wilde's boyfriend and his current age raised to the 0.23 power is 2.1520202182226886.\""
+      ]
+     },
+     "execution_count": 21,
      "metadata": {},
      "output_type": "execute_result"
     }
@@ -151,7 +252,7 @@
   {
    "cell_type": "code",
    "execution_count": null,
-   "id": "e7776981",
+   "id": "3450512e",
    "metadata": {},
    "outputs": [],
    "source": []

langchain/agents/tools.py

@@ -1,8 +1,10 @@
 """Interface for tools."""
-from typing import Callable, NamedTuple, Optional
+from dataclasses import dataclass
+from typing import Callable, Optional
 
 
-class Tool(NamedTuple):
+@dataclass
+class Tool:
     """Interface for tools."""
 
     name: str