init() — langchain Function Reference

Architecture documentation for the __init__() function in tool_emulator.py from the langchain codebase.

Function python LangChainCore MessageInterface

Entity Profile

LangChainCore→ MessageInterface→ __init__() — langchain Function Reference

Dependency Diagram

graph TD
  68fec0a7_58ea_3669_5538_184cad824113["__init__()"]
  a4266996_914c_18fd_7063_10ef49e72ec1["LLMToolEmulator"]
  68fec0a7_58ea_3669_5538_184cad824113 -->|defined in| a4266996_914c_18fd_7063_10ef49e72ec1
  style 68fec0a7_58ea_3669_5538_184cad824113 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

libs/langchain_v1/langchain/agents/middleware/tool_emulator.py lines 66–107

    def __init__(
        self,
        *,
        tools: list[str | BaseTool] | None = None,
        model: str | BaseChatModel | None = None,
    ) -> None:
        """Initialize the tool emulator.

        Args:
            tools: List of tool names (`str`) or `BaseTool` instances to emulate.

                If `None`, ALL tools will be emulated.

                If empty list, no tools will be emulated.
            model: Model to use for emulation.

                Defaults to `'anthropic:claude-sonnet-4-5-20250929'`.

                Can be a model identifier string or `BaseChatModel` instance.
        """
        super().__init__()

        # Extract tool names from tools
        # None means emulate all tools
        self.emulate_all = tools is None
        self.tools_to_emulate: set[str] = set()

        if not self.emulate_all and tools is not None:
            for tool in tools:
                if isinstance(tool, str):
                    self.tools_to_emulate.add(tool)
                else:
                    # Assume BaseTool with .name attribute
                    self.tools_to_emulate.add(tool.name)

        # Initialize emulator model
        if model is None:
            self.model = init_chat_model("anthropic:claude-sonnet-4-5-20250929", temperature=1)
        elif isinstance(model, BaseChatModel):
            self.model = model
        else:
            self.model = init_chat_model(model, temperature=1)