ChatAnthropic Class — langchain Architecture

Source Code

libs/partners/anthropic/langchain_anthropic/chat_models.py lines 741–1793

class ChatAnthropic(BaseChatModel):
    """Anthropic (Claude) chat models.

    See the [LangChain docs for `ChatAnthropic`](https://docs.langchain.com/oss/python/integrations/chat/anthropic)
    for tutorials, feature walkthroughs, and examples.

    See the [Claude Platform docs](https://platform.claude.com/docs/en/about-claude/models/overview)
    for a list of the latest models, their capabilities, and pricing.

    Example:
        ```python
        # pip install -U langchain-anthropic
        # export ANTHROPIC_API_KEY="your-api-key"

        from langchain_anthropic import ChatAnthropic

        model = ChatAnthropic(
            model="claude-sonnet-4-5-20250929",
            # temperature=,
            # max_tokens=,
            # timeout=,
            # max_retries=,
            # base_url="...",
            # Refer to API reference for full list of parameters
        )
        ```

    Note:
        Any param which is not explicitly supported will be passed directly to
        [`Anthropic.messages.create(...)`](https://platform.claude.com/docs/en/api/python/messages/create)
        each time to the model is invoked.
    """

    model_config = ConfigDict(
        populate_by_name=True,
    )

    model: str = Field(alias="model_name")
    """Model name to use."""

    max_tokens: int | None = Field(default=None, alias="max_tokens_to_sample")
    """Denotes the number of tokens to predict per generation.

    If not specified, this is set dynamically using the model's `max_output_tokens`
    from its model profile.

    See docs on [model profiles](https://docs.langchain.com/oss/python/langchain/models#model-profiles)
    for more information.
    """

    temperature: float | None = None
    """A non-negative float that tunes the degree of randomness in generation."""

    top_k: int | None = None
    """Number of most likely tokens to consider at each step."""

    top_p: float | None = None
    """Total probability mass of tokens to consider at each step."""

    default_request_timeout: float | None = Field(None, alias="timeout")
    """Timeout for requests to Claude API."""

    # sdk default = 2: https://github.com/anthropics/anthropic-sdk-python?tab=readme-ov-file#retries
    max_retries: int = 2
    """Number of retries allowed for requests sent to the Claude API."""

    stop_sequences: list[str] | None = Field(None, alias="stop")
    """Default stop sequences."""

    anthropic_api_url: str | None = Field(
        alias="base_url",
        default_factory=from_env(
            ["ANTHROPIC_API_URL", "ANTHROPIC_BASE_URL"],
            default="https://api.anthropic.com",
        ),
    )
    """Base URL for API requests. Only specify if using a proxy or service emulator.

    If a value isn't passed in, will attempt to read the value first from
    `ANTHROPIC_API_URL` and if that is not set, `ANTHROPIC_BASE_URL`.
    """