Defines a Calculator tool for performing basic math calculations.

This is an example of a pre-built LangChain.Function that is designed and configured for a specific purpose.

This defines a function to expose to an LLM and provides an implementation for the execute/2 function for evaluating when an LLM executes the function.

When using the Calculator tool, you will either need to:

• make repeated calls to run the chain as the tool is called and the results are then made available to the LLM before it returns the final result.
• OR run the chain using the while_needs_response: true option like this: LangChain.LLMChain.run(chain, while_needs_response: true)

Example

The following is an example that uses a prompt where math is needed. What follows is the verbose log output.

{:ok, updated_chain, %Message{} = message} =
  %{llm: ChatOpenAI.new!(%{temperature: 0}), verbose: true}
  |> LLMChain.new!()
  |> LLMChain.add_message(
    Message.new_user!("Answer the following math question: What is 100 + 300 - 200?")
  )
  |> LLMChain.add_functions(Calculator.new!())
  |> LLMChain.run(while_needs_response: true)

Verbose log output:

LLM: %LangChain.ChatModels.ChatOpenAI{
  endpoint: "https://api.openai.com/v1/chat/completions",
  model: "gpt-3.5-turbo",
  api_key: nil,
  temperature: 0.0,
  frequency_penalty: 0.0,
  receive_timeout: 60000,
  seed: 0,
  n: 1,
  json_response: false,
  stream: false,
  max_tokens: nil,
  user: nil
}
MESSAGES: [
  %LangChain.Message{
    content: "Answer the following math question: What is 100 + 300 - 200?",
    index: nil,
    status: :complete,
    role: :user,
    name: nil,
    tool_calls: [],
    tool_results: nil
  }
]
TOOLS: [
  %LangChain.Function{
    name: "calculator",
    description: "Perform basic math calculations or expressions",
    display_text: nil,
    function: #Function<0.75045395/2 in LangChain.Tools.Calculator.execute>,
    async: true,
    parameters_schema: %{
      type: "object",
      required: ["expression"],
      properties: %{
        expression: %{
          type: "string",
          description: "A simple mathematical expression"
        }
      }
    },
    parameters: []
  }
]
SINGLE MESSAGE RESPONSE: %LangChain.Message{
  content: nil,
  index: 0,
  status: :complete,
  role: :assistant,
  name: nil,
  tool_calls: [
    %LangChain.Message.ToolCall{
      status: :complete,
      type: :function,
      call_id: "call_NlHbo4R5NXTA6lHyjLdGQN9p",
      name: "calculator",
      arguments: %{"expression" => "100 + 300 - 200"},
      index: nil
    }
  ],
  tool_results: nil
}
EXECUTING FUNCTION: "calculator"
FUNCTION RESULT: "200"
TOOL RESULTS: %LangChain.Message{
  content: nil,
  index: nil,
  status: :complete,
  role: :tool,
  name: nil,
  tool_calls: [],
  tool_results: [
    %LangChain.Message.ToolResult{
      type: :function,
      tool_call_id: "call_NlHbo4R5NXTA6lHyjLdGQN9p",
      name: "calculator",
      content: "200",
      display_text: nil,
      is_error: false
    }
  ]
}
SINGLE MESSAGE RESPONSE: %LangChain.Message{
  content: "The result of the math question "100 + 300 - 200" is 200.",
  index: 0,
  status: :complete,
  role: :assistant,
  name: nil,
  tool_calls: [],
  tool_results: nil
}