Add Enum for agent types (#2321)

This pull request adds an enum class for the various types of agents
used in the project, located in the `agent_types.py` file. Currently,
the project is using hardcoded strings for the initialization of these
agents, which can lead to errors and make the code harder to maintain.
With the introduction of the new enums, the code will be more readable
and less error-prone.

The new enum members include:

- ZERO_SHOT_REACT_DESCRIPTION
- REACT_DOCSTORE
- SELF_ASK_WITH_SEARCH
- CONVERSATIONAL_REACT_DESCRIPTION
- CHAT_ZERO_SHOT_REACT_DESCRIPTION
- CHAT_CONVERSATIONAL_REACT_DESCRIPTION

In this PR, I have also replaced the hardcoded strings with the
appropriate enum members throughout the codebase, ensuring a smooth
transition to the new approach.

docs/modules/agents/agent_executors/examples/agent_vectorstore.ipynb

@@ -154,6 +154,7 @@
    "source": [
     "# Import things that are needed generically\n",
     "from langchain.agents import initialize_agent, Tool\n",
+    "from langchain.agents.agent_types import AgentType\n",
     "from langchain.tools import BaseTool\n",
     "from langchain.llms import OpenAI\n",
     "from langchain import LLMMathChain, SerpAPIWrapper"
@@ -189,7 +190,7 @@
    "source": [
     "# Construct the agent. We will use the default agent type here.\n",
     "# See documentation for a full list of options.\n",
-    "agent = initialize_agent(tools, llm, agent=\"zero-shot-react-description\", verbose=True)"
+    "agent = initialize_agent(tools, llm, agent=AgentType.ZERO_SHOT_REACT_DESCRIPTION, verbose=True)"
    ]
   },
   {
@@ -316,7 +317,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "agent = initialize_agent(tools, llm, agent=\"zero-shot-react-description\", verbose=True)"
+    "agent = initialize_agent(tools, llm, agent=AgentType.ZERO_SHOT_REACT_DESCRIPTION, verbose=True)"
    ]
   },
   {
@@ -433,7 +434,7 @@
    "source": [
     "# Construct the agent. We will use the default agent type here.\n",
     "# See documentation for a full list of options.\n",
-    "agent = initialize_agent(tools, llm, agent=\"zero-shot-react-description\", verbose=True)"
+    "agent = initialize_agent(tools, llm, agent=AgentType.ZERO_SHOT_REACT_DESCRIPTION, verbose=True)"
    ]
   },
   {

docs/modules/agents/agent_executors/examples/async_agent.ipynb

@@ -39,6 +39,7 @@
     "import time\n",
     "\n",
     "from langchain.agents import initialize_agent, load_tools\n",
+    "from langchain.agents.agent_types import AgentType\n",
     "from langchain.llms import OpenAI\n",
     "from langchain.callbacks.stdout import StdOutCallbackHandler\n",
     "from langchain.callbacks.base import CallbackManager\n",
@@ -175,7 +176,7 @@
     "        llm = OpenAI(temperature=0)\n",
     "        tools = load_tools([\"llm-math\", \"serpapi\"], llm=llm)\n",
     "        agent = initialize_agent(\n",
-    "            tools, llm, agent=\"zero-shot-react-description\", verbose=True\n",
+    "            tools, llm, agent=AgentType.ZERO_SHOT_REACT_DESCRIPTION verbose=True\n",
     "        )\n",
     "        agent.run(q)\n",
     "\n",
@@ -311,7 +312,7 @@
     "        llm = OpenAI(temperature=0, callback_manager=manager)\n",
     "        async_tools = load_tools([\"llm-math\", \"serpapi\"], llm=llm, aiosession=aiosession, callback_manager=manager)\n",
     "        agents.append(\n",
-    "            initialize_agent(async_tools, llm, agent=\"zero-shot-react-description\", verbose=True, callback_manager=manager)\n",
+    "            initialize_agent(async_tools, llm, agent=AgentType.ZERO_SHOT_REACT_DESCRIPTION, verbose=True, callback_manager=manager)\n",
     "        )\n",
     "    tasks = [async_agent.arun(q) for async_agent, q in zip(agents, questions)]\n",
     "    await asyncio.gather(*tasks)\n",
@@ -381,7 +382,7 @@
     "llm = OpenAI(temperature=0, callback_manager=manager)\n",
     "\n",
     "async_tools = load_tools([\"llm-math\", \"serpapi\"], llm=llm, aiosession=aiosession)\n",
-    "async_agent = initialize_agent(async_tools, llm, agent=\"zero-shot-react-description\", verbose=True, callback_manager=manager)\n",
+    "async_agent = initialize_agent(async_tools, llm, agent=AgentType.ZERO_SHOT_REACT_DESCRIPTION, verbose=True, callback_manager=manager)\n",
     "await async_agent.arun(questions[0])\n",
     "await aiosession.close()"
    ]

docs/modules/agents/agent_executors/examples/intermediate_steps.ipynb

@@ -19,6 +19,7 @@
    "source": [
     "from langchain.agents import load_tools\n",
     "from langchain.agents import initialize_agent\n",
+    "from langchain.agents.agent_types import AgentType\n",
     "from langchain.llms import OpenAI"
    ]
   },
@@ -56,7 +57,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "agent = initialize_agent(tools, llm, agent=\"zero-shot-react-description\", verbose=True, return_intermediate_steps=True)"
+    "agent = initialize_agent(tools, llm, agent=AgentType.ZERO_SHOT_REACT_DESCRIPTION, verbose=True, return_intermediate_steps=True)"
    ]
   },
   {

docs/modules/agents/agent_executors/examples/max_iterations.ipynb

@@ -19,6 +19,7 @@
    "source": [
     "from langchain.agents import load_tools\n",
     "from langchain.agents import initialize_agent, Tool\n",
+    "from langchain.agents.agent_types import AgentType\n",
     "from langchain.llms import OpenAI"
    ]
   },
@@ -59,7 +60,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "agent = initialize_agent(tools, llm, agent=\"zero-shot-react-description\", verbose=True)"
+    "agent = initialize_agent(tools, llm, agent=AgentType.ZERO_SHOT_REACT_DESCRIPTION, verbose=True)"
    ]
   },
   {
@@ -139,7 +140,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "agent = initialize_agent(tools, llm, agent=\"zero-shot-react-description\", verbose=True, max_iterations=2)"
+    "agent = initialize_agent(tools, llm, agent=AgentType.ZERO_SHOT_REACT_DESCRIPTION, verbose=True, max_iterations=2)"
    ]
   },
   {
@@ -198,7 +199,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "agent = initialize_agent(tools, llm, agent=\"zero-shot-react-description\", verbose=True, max_iterations=2, early_stopping_method=\"generate\")"
+    "agent = initialize_agent(tools, llm, agent=AgentType.ZERO_SHOT_REACT_DESCRIPTION, verbose=True, max_iterations=2, early_stopping_method=\"generate\")"
    ]
   },
   {

docs/modules/agents/agents/examples/chat_conversation_agent.ipynb

@@ -34,7 +34,8 @@
     "from langchain.memory import ConversationBufferMemory\n",
     "from langchain.chat_models import ChatOpenAI\n",
     "from langchain.utilities import SerpAPIWrapper\n",
-    "from langchain.agents import initialize_agent"
+    "from langchain.agents import initialize_agent\n",
+    "from langchain.agents.agent_types import AgentType"
    ]
   },
   {
@@ -72,7 +73,7 @@
    "outputs": [],
    "source": [
     "llm=ChatOpenAI(temperature=0)\n",
-    "agent_chain = initialize_agent(tools, llm, agent=\"chat-conversational-react-description\", verbose=True, memory=memory)"
+    "agent_chain = initialize_agent(tools, llm, agent=AgentType.CHAT_CONVERSATIONAL_REACT_DESCRIPTION, verbose=True, memory=memory)"
    ]
   },
   {

docs/modules/agents/agents/examples/conversational_agent.ipynb

@@ -20,6 +20,7 @@
    "outputs": [],
    "source": [
     "from langchain.agents import Tool\n",
+    "from langchain.agents.agent_types import AgentType\n",
     "from langchain.memory import ConversationBufferMemory\n",
     "from langchain import OpenAI\n",
     "from langchain.utilities import GoogleSearchAPIWrapper\n",
@@ -61,7 +62,7 @@
    "outputs": [],
    "source": [
     "llm=OpenAI(temperature=0)\n",
-    "agent_chain = initialize_agent(tools, llm, agent=\"conversational-react-description\", verbose=True, memory=memory)"
+    "agent_chain = initialize_agent(tools, llm, agent=AgentType.CONVERSATIONAL_REACT_DESCRIPTION, verbose=True, memory=memory)"
    ]
   },
   {

docs/modules/agents/agents/examples/mrkl.ipynb

@@ -27,7 +27,8 @@
    "outputs": [],
    "source": [
     "from langchain import LLMMathChain, OpenAI, SerpAPIWrapper, SQLDatabase, SQLDatabaseChain\n",
-    "from langchain.agents import initialize_agent, Tool"
+    "from langchain.agents import initialize_agent, Tool\n",
+    "from langchain.agents.agent_types import AgentType"
    ]
   },
   {
@@ -68,7 +69,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "mrkl = initialize_agent(tools, llm, agent=\"zero-shot-react-description\", verbose=True)"
+    "mrkl = initialize_agent(tools, llm, agent=AgentType.ZERO_SHOT_REACT_DESCRIPTION, verbose=True)"
    ]
   },
   {

docs/modules/agents/agents/examples/mrkl_chat.ipynb

@@ -28,6 +28,7 @@
    "source": [
     "from langchain import OpenAI, LLMMathChain, SerpAPIWrapper, SQLDatabase, SQLDatabaseChain\n",
     "from langchain.agents import initialize_agent, Tool\n",
+    "from langchain.agents.agent_types import AgentType\n",
     "from langchain.chat_models import ChatOpenAI"
    ]
   },
@@ -70,7 +71,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "mrkl = initialize_agent(tools, llm, agent=\"chat-zero-shot-react-description\", verbose=True)"
+    "mrkl = initialize_agent(tools, llm, agent=AgentType.CHAT_ZERO_SHOT_REACT_DESCRIPTION, verbose=True)"
    ]
   },
   {

docs/modules/agents/agents/examples/react.ipynb

@@ -19,6 +19,7 @@
    "source": [
     "from langchain import OpenAI, Wikipedia\n",
     "from langchain.agents import initialize_agent, Tool\n",
+    "from langchain.agents.agent_types import AgentType\n",
     "from langchain.agents.react.base import DocstoreExplorer\n",
     "docstore=DocstoreExplorer(Wikipedia())\n",
     "tools = [\n",
@@ -35,7 +36,7 @@
     "]\n",
     "\n",
     "llm = OpenAI(temperature=0, model_name=\"text-davinci-002\")\n",
-    "react = initialize_agent(tools, llm, agent=\"react-docstore\", verbose=True)"
+    "react = initialize_agent(tools, llm, agent=AgentType.REACT_DOCSTORE, verbose=True)"
    ]
   },
   {

docs/modules/agents/agents/examples/self_ask_with_search.ipynb

@@ -46,6 +46,7 @@
    "source": [
     "from langchain import OpenAI, SerpAPIWrapper\n",
     "from langchain.agents import initialize_agent, Tool\n",
+    "from langchain.agents.agent_types import AgentType\n",
     "\n",
     "llm = OpenAI(temperature=0)\n",
     "search = SerpAPIWrapper()\n",
@@ -57,7 +58,7 @@
     "    )\n",
     "]\n",
     "\n",
-    "self_ask_with_search = initialize_agent(tools, llm, agent=\"self-ask-with-search\", verbose=True)\n",
+    "self_ask_with_search = initialize_agent(tools, llm, agent=AgentType.SELF_ASK_WITH_SEARCH, verbose=True)\n",
     "self_ask_with_search.run(\"What is the hometown of the reigning men's U.S. Open champion?\")"
    ]
   }

docs/modules/agents/getting_started.ipynb

@@ -92,7 +92,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "agent = initialize_agent(tools, llm, agent=\"zero-shot-react-description\", verbose=True)"
+    "agent = initialize_agent(tools, llm, agent=AgentType.ZERO_SHOT_REACT_DESCRIPTION, verbose=True)"
    ]
   },
   {

docs/modules/agents/tools/custom_tools.ipynb

@@ -27,6 +27,7 @@
    "source": [
     "# Import things that are needed generically\n",
     "from langchain.agents import initialize_agent, Tool\n",
+    "from langchain.agents.agent_types import AgentType\n",
     "from langchain.tools import BaseTool\n",
     "from langchain.llms import OpenAI\n",
     "from langchain import LLMMathChain, SerpAPIWrapper"
@@ -102,7 +103,7 @@
    "source": [
     "# Construct the agent. We will use the default agent type here.\n",
     "# See documentation for a full list of options.\n",
-    "agent = initialize_agent(tools, llm, agent=\"zero-shot-react-description\", verbose=True)"
+    "agent = initialize_agent(tools, llm, agent=AgentType.ZERO_SHOT_REACT_DESCRIPTION, verbose=True)"
    ]
   },
   {
@@ -217,7 +218,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "agent = initialize_agent(tools, llm, agent=\"zero-shot-react-description\", verbose=True)"
+    "agent = initialize_agent(tools, llm, agent=AgentType.ZERO_SHOT_REACT_DESCRIPTION, verbose=True)"
    ]
   },
   {
@@ -410,7 +411,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "agent = initialize_agent(tools, llm, agent=\"zero-shot-react-description\", verbose=True)"
+    "agent = initialize_agent(tools, llm, agent=AgentType.ZERO_SHOT_REACT_DESCRIPTION, verbose=True)"
    ]
   },
   {
@@ -484,6 +485,7 @@
    "source": [
     "# Import things that are needed generically\n",
     "from langchain.agents import initialize_agent, Tool\n",
+    "from langchain.agents.agent_types import AgentType\n",
     "from langchain.llms import OpenAI\n",
     "from langchain import LLMMathChain, SerpAPIWrapper\n",
     "search = SerpAPIWrapper()\n",
@@ -500,7 +502,7 @@
     "    )\n",
     "]\n",
     "\n",
-    "agent = initialize_agent(tools, OpenAI(temperature=0), agent=\"zero-shot-react-description\", verbose=True)"
+    "agent = initialize_agent(tools, OpenAI(temperature=0), agent=AgentType.ZERO_SHOT_REACT_DESCRIPTION, verbose=True)"
    ]
   },
   {
@@ -576,7 +578,7 @@
    "outputs": [],
    "source": [
     "llm = OpenAI(temperature=0)\n",
-    "agent = initialize_agent(tools, llm, agent=\"zero-shot-react-description\", verbose=True)"
+    "agent = initialize_agent(tools, llm, agent=AgentType.ZERO_SHOT_REACT_DESCRIPTION, verbose=True)"
    ]
   },
   {

docs/modules/agents/tools/examples/chatgpt_plugins.ipynb

@@ -23,6 +23,7 @@
    "source": [
     "from langchain.chat_models import ChatOpenAI\n",
     "from langchain.agents import load_tools, initialize_agent\n",
+    "from langchain.agents.agent_types import AgentType\n",
     "from langchain.tools import AIPluginTool"
    ]
   },
@@ -83,7 +84,7 @@
     "tools = load_tools([\"requests\"] )\n",
     "tools += [tool]\n",
     "\n",
-    "agent_chain = initialize_agent(tools, llm, agent=\"zero-shot-react-description\", verbose=True)\n",
+    "agent_chain = initialize_agent(tools, llm, agent=AgentType.ZERO_SHOT_REACT_DESCRIPTION verbose=True)\n",
     "agent_chain.run(\"what t shirts are available in klarna?\")"
    ]
   },

docs/modules/agents/tools/examples/google_serper.ipynb

@@ -115,6 +115,7 @@
     "from langchain.utilities import GoogleSerperAPIWrapper\n",
     "from langchain.llms.openai import OpenAI\n",
     "from langchain.agents import initialize_agent, Tool\n",
+    "from langchain.agents.agent_types import AgentType\n",
     "\n",
     "llm = OpenAI(temperature=0)\n",
     "search = GoogleSerperAPIWrapper()\n",
@@ -126,7 +127,7 @@
     "    )\n",
     "]\n",
     "\n",
-    "self_ask_with_search = initialize_agent(tools, llm, agent=\"self-ask-with-search\", verbose=True)\n",
+    "self_ask_with_search = initialize_agent(tools, llm, agent=AgentType.SELF_ASK_WITH_SEARCH, verbose=True)\n",
     "self_ask_with_search.run(\"What is the hometown of the reigning men's U.S. Open champion?\")"
    ],
    "metadata": {

docs/modules/agents/tools/examples/human_tools.ipynb

@@ -20,6 +20,7 @@
     "from langchain.chat_models import ChatOpenAI\n",
     "from langchain.llms import OpenAI\n",
     "from langchain.agents import load_tools, initialize_agent\n",
+    "from langchain.agents.agent_types import AgentType\n",
     "\n",
     "llm = ChatOpenAI(temperature=0.0)\n",
     "math_llm = OpenAI(temperature=0.0)\n",
@@ -31,7 +32,7 @@
     "agent_chain = initialize_agent(\n",
     "    tools,\n",
     "    llm,\n",
-    "    agent=\"zero-shot-react-description\",\n",
+    "    agent=AgentType.ZERO_SHOT_REACT_DESCRIPTION,\n",
     "    verbose=True,\n",
     ")"
    ]

docs/modules/agents/tools/examples/search_tools.ipynb

@@ -23,6 +23,7 @@
    "source": [
     "from langchain.agents import load_tools\n",
     "from langchain.agents import initialize_agent\n",
+    "from langchain.agents.agent_types import AgentType\n",
     "from langchain.llms import OpenAI"
    ]
   },
@@ -63,7 +64,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "agent = initialize_agent(tools, llm, agent=\"zero-shot-react-description\", verbose=True)"
+    "agent = initialize_agent(tools, llm, agent=AgentType.ZERO_SHOT_REACT_DESCRIPTION, verbose=True)"
    ]
   },
   {
@@ -131,7 +132,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "agent = initialize_agent(tools, llm, agent=\"zero-shot-react-description\", verbose=True)"
+    "agent = initialize_agent(tools, llm, agent=AgentType.ZERO_SHOT_REACT_DESCRIPTION, verbose=True)"
    ]
   },
   {
@@ -199,7 +200,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "agent = initialize_agent(tools, llm, agent=\"zero-shot-react-description\", verbose=True)"
+    "agent = initialize_agent(tools, llm, agent=AgentType.ZERO_SHOT_REACT_DESCRIPTION, verbose=True)"
    ]
   },
   {
@@ -266,7 +267,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "agent = initialize_agent(tools, llm, agent=\"zero-shot-react-description\", verbose=True)"
+    "agent = initialize_agent(tools, llm, agent=AgentType.ZERO_SHOT_REACT_DESCRIPTION, verbose=True)"
    ]
   },
   {

docs/modules/agents/tools/examples/zapier.ipynb

@@ -77,6 +77,7 @@
     "from langchain.llms import OpenAI\n",
     "from langchain.agents import initialize_agent\n",
     "from langchain.agents.agent_toolkits import ZapierToolkit\n",
+    "from langchain.agents.agent_types import AgentType\n",
     "from langchain.utilities.zapier import ZapierNLAWrapper"
    ]
   },
@@ -105,7 +106,7 @@
     "llm = OpenAI(temperature=0)\n",
     "zapier = ZapierNLAWrapper()\n",
     "toolkit = ZapierToolkit.from_zapier_nla_wrapper(zapier)\n",
-    "agent = initialize_agent(toolkit.get_tools(), llm, agent=\"zero-shot-react-description\", verbose=True)"
+    "agent = initialize_agent(toolkit.get_tools(), llm, agent=AgentType.ZERO_SHOT_REACT_DESCRIPTION, verbose=True)"
    ]
   },
   {

docs/modules/agents/tools/multi_input_tool.ipynb

@@ -23,7 +23,8 @@
    "outputs": [],
    "source": [
     "from langchain.llms import OpenAI\n",
-    "from langchain.agents import initialize_agent, Tool"
+    "from langchain.agents import initialize_agent, Tool\n",
+    "from langchain.agents.agent_types import AgentType"
    ]
   },
   {
@@ -64,7 +65,7 @@
     "        description=\"useful for when you need to multiply two numbers together. The input to this tool should be a comma separated list of numbers of length two, representing the two numbers you want to multiply together. For example, `1,2` would be the input if you wanted to multiply 1 by 2.\"\n",
     "    )\n",
     "]\n",
-    "mrkl = initialize_agent(tools, llm, agent=\"zero-shot-react-description\", verbose=True)"
+    "mrkl = initialize_agent(tools, llm, agent=AgentType.ZERO_SHOT_REACT_DESCRIPTION, verbose=True)"
    ]
   },
   {