Files
langchain/libs/partners/anthropic/langchain_anthropic/chat_models.py
Mason Daugherty 7a4594b682 fix(anthropic): restore cache_control on non-direct subclasses (#37057)
Closes #37042

---

`AnthropicPromptCachingMiddleware` was unconditionally setting top-level
`cache_control` in `model_settings` for any `ChatAnthropic` subclass.
That field is direct-Anthropic-API only — `ChatAnthropicBedrock` (which
subclasses `ChatAnthropic` and passed the existing `isinstance` gate)
errored with `cache_control: Extra inputs are not permitted`.
Investigating that surfaced a related regression: PR #35967 also deleted
the block-level `cache_control` injection in `_get_request_payload`,
which silently disabled caching entirely for non-direct subclasses
(Bedrock had been falling back to in-block breakpoints). This restores
both paths.

## Changes
- Add `_is_direct_anthropic_llm_type` predicate that allowlists
`_llm_type == "anthropic-chat"`. Both the middleware's
`_supports_automatic_caching` and the new branch in
`ChatAnthropic._get_request_payload` route through it, so any subclass
that overrides `_llm_type` (Bedrock today, future direct-API variants
tomorrow) is treated as non-direct by default. Replaces the prior
substring-matching denylist on `"bedrock"`/`"vertex"`.
- Restore `_collect_code_execution_tool_ids`,
`_is_code_execution_related_block`, and a new
`_apply_cache_control_to_last_eligible_block` helper in `chat_models`.
For non-direct subclasses, `_get_request_payload` now pops
`cache_control` from kwargs and walks messages newest-to-oldest,
attaching the breakpoint to the last block that isn't
`code_execution`-related (Anthropic forbids breakpoints on those).
- Emit `UserWarning` when `cache_control` is requested but every
candidate block is `code_execution`-related — previously a silent drop.
- `AnthropicPromptCachingMiddleware._apply_caching` now sets the
top-level `cache_control` only when
`_supports_automatic_caching(request.model)`. System-message and
tool-definition breakpoints continue to apply for all `ChatAnthropic`
subclasses, since those are accepted by every transport.
- Note: `ChatAnthropicVertex` does not subclass `ChatAnthropic` (it
lives in `langchain-google-vertexai` and ships its own
`_get_request_payload`), so the chat-models changes here only affect
Bedrock. The middleware-side gate covers Vertex implicitly via the
`isinstance(request.model, ChatAnthropic)` check that already excludes
it.
2026-04-28 16:41:22 -04:00

2304 lines
90 KiB
Python

"""Anthropic chat models."""
from __future__ import annotations
import copy
import datetime
import json
import re
import warnings
from collections.abc import AsyncIterator, Callable, Iterator, Mapping, Sequence
from functools import cached_property
from operator import itemgetter
from typing import Any, Final, Literal, cast
import anthropic
from langchain_core.callbacks import (
AsyncCallbackManagerForLLMRun,
CallbackManagerForLLMRun,
)
from langchain_core.exceptions import ContextOverflowError, OutputParserException
from langchain_core.language_models import (
LanguageModelInput,
ModelProfile,
ModelProfileRegistry,
)
from langchain_core.language_models.chat_models import BaseChatModel, LangSmithParams
from langchain_core.messages import (
AIMessage,
AIMessageChunk,
BaseMessage,
HumanMessage,
SystemMessage,
ToolCall,
ToolMessage,
is_data_content_block,
)
from langchain_core.messages import content as types
from langchain_core.messages.ai import InputTokenDetails, UsageMetadata
from langchain_core.messages.tool import tool_call_chunk as create_tool_call_chunk
from langchain_core.output_parsers import (
JsonOutputKeyToolsParser,
JsonOutputParser,
PydanticOutputParser,
PydanticToolsParser,
)
from langchain_core.output_parsers.base import OutputParserLike
from langchain_core.outputs import ChatGeneration, ChatGenerationChunk, ChatResult
from langchain_core.runnables import Runnable, RunnableMap, RunnablePassthrough
from langchain_core.tools import BaseTool
from langchain_core.utils import from_env, get_pydantic_field_names, secret_from_env
from langchain_core.utils.function_calling import (
convert_to_json_schema,
convert_to_openai_tool,
)
from langchain_core.utils.pydantic import is_basemodel_subclass
from langchain_core.utils.utils import _build_model_kwargs
from pydantic import BaseModel, ConfigDict, Field, SecretStr, model_validator
from typing_extensions import NotRequired, TypedDict
from langchain_anthropic import __version__
from langchain_anthropic._client_utils import (
_get_default_async_httpx_client,
_get_default_httpx_client,
)
from langchain_anthropic._compat import _convert_from_v1_to_anthropic
from langchain_anthropic.data._profiles import _PROFILES
from langchain_anthropic.output_parsers import extract_tool_calls
_message_type_lookups = {
"human": "user",
"ai": "assistant",
"AIMessageChunk": "assistant",
"HumanMessageChunk": "user",
}
_MODEL_PROFILES = cast(ModelProfileRegistry, _PROFILES)
_USER_AGENT: Final[str] = f"langchain-anthropic/{__version__}"
def _get_default_model_profile(model_name: str) -> ModelProfile:
"""Get the default profile for a model.
Args:
model_name: The model identifier.
Returns:
The model profile dictionary, or an empty dict if not found.
"""
default = _MODEL_PROFILES.get(model_name)
if default:
return default.copy()
return {}
_FALLBACK_MAX_OUTPUT_TOKENS: Final[int] = 4096
class AnthropicTool(TypedDict):
"""Anthropic tool definition for custom (user-defined) tools.
Custom tools use `name` and `input_schema` fields to define the tool's
interface. These are converted from LangChain tool formats (functions, Pydantic
models, `BaseTool` objects) via `convert_to_anthropic_tool`.
"""
name: str
input_schema: dict[str, Any]
description: NotRequired[str]
strict: NotRequired[bool]
cache_control: NotRequired[dict[str, str]]
defer_loading: NotRequired[bool]
input_examples: NotRequired[list[dict[str, Any]]]
allowed_callers: NotRequired[list[str]]
# ---------------------------------------------------------------------------
# Built-in Tool Support
# ---------------------------------------------------------------------------
# When Anthropic releases new built-in tools, two places may need updating:
#
# 1. _TOOL_TYPE_TO_BETA (below) - Add mapping if the tool requires a beta header.
# Not all tools need this; only add if the API requires a beta header.
#
# 2. _is_builtin_tool() - Add the tool type prefix to _BUILTIN_TOOL_PREFIXES.
# This ensures the tool dict is passed through to the API unchanged (instead
# of being converted via convert_to_anthropic_tool, which may fail).
# ---------------------------------------------------------------------------
_TOOL_TYPE_TO_BETA: dict[str, str] = {
"web_fetch_20250910": "web-fetch-2025-09-10",
"code_execution_20250522": "code-execution-2025-05-22",
"code_execution_20250825": "code-execution-2025-08-25",
"mcp_toolset": "mcp-client-2025-11-20",
"memory_20250818": "context-management-2025-06-27",
"computer_20250124": "computer-use-2025-01-24",
"computer_20251124": "computer-use-2025-11-24",
"tool_search_tool_regex_20251119": "advanced-tool-use-2025-11-20",
"tool_search_tool_bm25_20251119": "advanced-tool-use-2025-11-20",
}
"""Mapping of tool type to required beta header.
Some tool types require specific beta headers to be enabled.
"""
_BUILTIN_TOOL_PREFIXES = [
"text_editor_",
"computer_",
"bash_",
"web_search_",
"web_fetch_",
"code_execution_",
"mcp_toolset",
"memory_",
"tool_search_",
]
_ANTHROPIC_EXTRA_FIELDS: set[str] = {
"allowed_callers",
"cache_control",
"defer_loading",
"eager_input_streaming",
"input_examples",
}
"""Valid Anthropic-specific extra fields"""
def _is_builtin_tool(tool: Any) -> bool:
"""Check if a tool is a built-in (server-side) Anthropic tool.
`tool` must be a `dict` and have a `type` key starting with one of the known
built-in tool prefixes.
[Claude docs](https://platform.claude.com/docs/en/agents-and-tools/tool-use/overview)
"""
if not isinstance(tool, dict):
return False
tool_type = tool.get("type")
if not tool_type or not isinstance(tool_type, str):
return False
return any(tool_type.startswith(prefix) for prefix in _BUILTIN_TOOL_PREFIXES)
def _format_image(url: str) -> dict:
"""Convert part["image_url"]["url"] strings (OpenAI format) to Anthropic format.
{
"type": "base64",
"media_type": "image/jpeg",
"data": "/9j/4AAQSkZJRg...",
}
Or
{
"type": "url",
"url": "https://example.com/image.jpg",
}
"""
# Base64 encoded image
base64_regex = r"^data:(?P<media_type>image/.+);base64,(?P<data>.+)$"
base64_match = re.match(base64_regex, url)
if base64_match:
return {
"type": "base64",
"media_type": base64_match.group("media_type"),
"data": base64_match.group("data"),
}
# Url
url_regex = r"^https?://.*$"
url_match = re.match(url_regex, url)
if url_match:
return {
"type": "url",
"url": url,
}
msg = (
"Malformed url parameter."
" Must be either an image URL (https://example.com/image.jpg)"
" or base64 encoded string (data:image/png;base64,'/9j/4AAQSk'...)"
)
raise ValueError(
msg,
)
def _merge_messages(
messages: Sequence[BaseMessage],
) -> list[SystemMessage | AIMessage | HumanMessage]:
"""Merge runs of human/tool messages into single human messages with content blocks.""" # noqa: E501
merged: list = []
for curr in messages:
if isinstance(curr, ToolMessage):
if (
isinstance(curr.content, list)
and curr.content
and all(
isinstance(block, dict) and block.get("type") == "tool_result"
for block in curr.content
)
):
curr = HumanMessage(curr.content) # type: ignore[misc]
else:
tool_content = curr.content
cache_ctrl = None
# Extract cache_control from content blocks and hoist it
# to the tool_result level. Anthropic's API does not
# support cache_control on tool_result content sub-blocks.
if isinstance(tool_content, list):
cleaned = []
for block in tool_content:
if isinstance(block, dict) and "cache_control" in block:
cache_ctrl = block["cache_control"]
block = {
k: v for k, v in block.items() if k != "cache_control"
}
cleaned.append(block)
tool_content = cleaned
tool_result: dict = {
"type": "tool_result",
"content": tool_content,
"tool_use_id": curr.tool_call_id,
"is_error": curr.status == "error",
}
if cache_ctrl:
tool_result["cache_control"] = cache_ctrl
curr = HumanMessage( # type: ignore[misc]
[tool_result],
)
last = merged[-1] if merged else None
if any(
all(isinstance(m, c) for m in (curr, last))
for c in (SystemMessage, HumanMessage)
):
if isinstance(cast("BaseMessage", last).content, str):
new_content: list = [
{"type": "text", "text": cast("BaseMessage", last).content},
]
else:
new_content = copy.copy(cast("list", cast("BaseMessage", last).content))
if isinstance(curr.content, str):
new_content.append({"type": "text", "text": curr.content})
else:
new_content.extend(curr.content)
merged[-1] = curr.model_copy(update={"content": new_content})
else:
merged.append(curr)
return merged
def _format_data_content_block(block: dict) -> dict:
"""Format standard data content block to format expected by Anthropic."""
if block["type"] == "image":
if "url" in block:
if block["url"].startswith("data:"):
# Data URI
formatted_block = {
"type": "image",
"source": _format_image(block["url"]),
}
else:
formatted_block = {
"type": "image",
"source": {"type": "url", "url": block["url"]},
}
elif "base64" in block or block.get("source_type") == "base64":
formatted_block = {
"type": "image",
"source": {
"type": "base64",
"media_type": block["mime_type"],
"data": block.get("base64") or block.get("data", ""),
},
}
elif "file_id" in block:
formatted_block = {
"type": "image",
"source": {
"type": "file",
"file_id": block["file_id"],
},
}
elif block.get("source_type") == "id":
formatted_block = {
"type": "image",
"source": {
"type": "file",
"file_id": block["id"],
},
}
else:
msg = (
"Anthropic only supports 'url', 'base64', or 'id' keys for image "
"content blocks."
)
raise ValueError(
msg,
)
elif block["type"] == "file":
if "url" in block:
formatted_block = {
"type": "document",
"source": {
"type": "url",
"url": block["url"],
},
}
elif "base64" in block or block.get("source_type") == "base64":
formatted_block = {
"type": "document",
"source": {
"type": "base64",
"media_type": block.get("mime_type") or "application/pdf",
"data": block.get("base64") or block.get("data", ""),
},
}
elif block.get("source_type") == "text":
formatted_block = {
"type": "document",
"source": {
"type": "text",
"media_type": block.get("mime_type") or "text/plain",
"data": block["text"],
},
}
elif "file_id" in block:
formatted_block = {
"type": "document",
"source": {
"type": "file",
"file_id": block["file_id"],
},
}
elif block.get("source_type") == "id":
formatted_block = {
"type": "document",
"source": {
"type": "file",
"file_id": block["id"],
},
}
else:
msg = (
"Anthropic only supports 'url', 'base64', or 'id' keys for file "
"content blocks."
)
raise ValueError(msg)
elif block["type"] == "text-plain":
formatted_block = {
"type": "document",
"source": {
"type": "text",
"media_type": block.get("mime_type") or "text/plain",
"data": block["text"],
},
}
else:
msg = f"Block of type {block['type']} is not supported."
raise ValueError(msg)
if formatted_block:
for key in ["cache_control", "citations", "title", "context"]:
if key in block:
formatted_block[key] = block[key]
elif (metadata := block.get("extras")) and key in metadata:
formatted_block[key] = metadata[key]
elif (metadata := block.get("metadata")) and key in metadata:
# Backward compat
formatted_block[key] = metadata[key]
return formatted_block
def _format_messages(
messages: Sequence[BaseMessage],
) -> tuple[str | list[dict] | None, list[dict]]:
"""Format messages for Anthropic's API."""
system: str | list[dict] | None = None
formatted_messages: list[dict] = []
merged_messages = _merge_messages(messages)
for _i, message in enumerate(merged_messages):
if message.type == "system":
if system is not None:
msg = "Received multiple non-consecutive system messages."
raise ValueError(msg)
if isinstance(message.content, list):
system = [
(
block
if isinstance(block, dict)
else {"type": "text", "text": block}
)
for block in message.content
]
else:
system = message.content
continue
role = _message_type_lookups[message.type]
content: str | list
if not isinstance(message.content, str):
# parse as dict
if not isinstance(message.content, list):
msg = "Anthropic message content must be str or list of dicts"
raise ValueError(
msg,
)
# populate content
content = []
for block in message.content:
if isinstance(block, str):
content.append({"type": "text", "text": block})
elif isinstance(block, dict):
if "type" not in block:
msg = "Dict content block must have a type key"
raise ValueError(msg)
if block["type"] in ("reasoning", "function_call") and (
not isinstance(message, AIMessage)
or message.response_metadata.get("model_provider")
!= "anthropic"
):
continue
if block["type"] == "image_url":
# convert format
source = _format_image(block["image_url"]["url"])
content.append({"type": "image", "source": source})
elif is_data_content_block(block):
content.append(_format_data_content_block(block))
elif block["type"] == "tool_use":
# If a tool_call with the same id as a tool_use content block
# exists, the tool_call is preferred.
if (
isinstance(message, AIMessage)
and (block["id"] in [tc["id"] for tc in message.tool_calls])
and not block.get("caller")
):
overlapping = [
tc
for tc in message.tool_calls
if tc["id"] == block["id"]
]
content.extend(
_lc_tool_calls_to_anthropic_tool_use_blocks(
overlapping,
),
)
else:
if tool_input := block.get("input"):
args = tool_input
elif "partial_json" in block:
try:
args = json.loads(block["partial_json"] or "{}")
except json.JSONDecodeError:
args = {}
else:
args = {}
tool_use_block = _AnthropicToolUse(
type="tool_use",
name=block["name"],
input=args,
id=block["id"],
)
if caller := block.get("caller"):
tool_use_block["caller"] = caller
content.append(tool_use_block)
elif block["type"] in ("server_tool_use", "mcp_tool_use"):
formatted_block = {
k: v
for k, v in block.items()
if k
in (
"type",
"id",
"input",
"name",
"server_name", # for mcp_tool_use
"cache_control",
)
}
# Attempt to parse streamed output
if block.get("input") == {} and "partial_json" in block:
try:
input_ = json.loads(block["partial_json"])
if input_:
formatted_block["input"] = input_
except json.JSONDecodeError:
pass
content.append(formatted_block)
elif block["type"] == "text":
text = block.get("text", "")
# Only add non-empty strings for now as empty ones are not
# accepted.
# https://github.com/anthropics/anthropic-sdk-python/issues/461
if text.strip():
formatted_block = {
k: v
for k, v in block.items()
if k in ("type", "text", "cache_control", "citations")
}
# Clean up citations to remove null file_id fields
if formatted_block.get("citations"):
cleaned_citations = []
for citation in formatted_block["citations"]:
cleaned_citation = {
k: v
for k, v in citation.items()
if not (k == "file_id" and v is None)
}
cleaned_citations.append(cleaned_citation)
formatted_block["citations"] = cleaned_citations
content.append(formatted_block)
elif block["type"] == "thinking":
content.append(
{
k: v
for k, v in block.items()
if k
in ("type", "thinking", "cache_control", "signature")
},
)
elif block["type"] == "redacted_thinking":
content.append(
{
k: v
for k, v in block.items()
if k in ("type", "cache_control", "data")
},
)
elif (
block["type"] == "tool_result"
and isinstance(block.get("content"), list)
and any(
isinstance(item, dict)
and item.get("type") == "tool_reference"
for item in block["content"]
)
):
# Tool search results with tool_reference blocks
content.append(
{
k: v
for k, v in block.items()
if k
in (
"type",
"content",
"tool_use_id",
"cache_control",
)
},
)
elif block["type"] == "tool_result":
# Regular tool results that need content formatting
tool_content = _format_messages(
[HumanMessage(block["content"])],
)[1][0]["content"]
content.append({**block, "content": tool_content})
elif block["type"] in (
"code_execution_tool_result",
"bash_code_execution_tool_result",
"text_editor_code_execution_tool_result",
"mcp_tool_result",
"web_search_tool_result",
"web_fetch_tool_result",
):
content.append(
{
k: v
for k, v in block.items()
if k
in (
"type",
"content",
"tool_use_id",
"is_error", # for mcp_tool_result
"cache_control",
"retrieved_at", # for web_fetch_tool_result
)
},
)
else:
content.append(block)
else:
msg = (
f"Content blocks must be str or dict, instead was: "
f"{type(block)}"
)
raise ValueError(
msg,
)
else:
content = message.content
# Ensure all tool_calls have a tool_use content block
if isinstance(message, AIMessage) and message.tool_calls:
content = content or []
content = (
[{"type": "text", "text": message.content}]
if isinstance(content, str) and content
else content
)
tool_use_ids = [
cast("dict", block)["id"]
for block in content
if cast("dict", block)["type"] == "tool_use"
]
missing_tool_calls = [
tc for tc in message.tool_calls if tc["id"] not in tool_use_ids
]
cast("list", content).extend(
_lc_tool_calls_to_anthropic_tool_use_blocks(missing_tool_calls),
)
if role == "assistant" and _i == len(merged_messages) - 1:
if isinstance(content, str):
content = content.rstrip()
elif (
isinstance(content, list)
and content
and isinstance(content[-1], dict)
and content[-1].get("type") == "text"
):
content[-1]["text"] = content[-1]["text"].rstrip()
if not content and role == "assistant" and _i < len(merged_messages) - 1:
# anthropic.BadRequestError: Error code: 400: all messages must have
# non-empty content except for the optional final assistant message
continue
formatted_messages.append({"role": role, "content": content})
return system, formatted_messages
def _collect_code_execution_tool_ids(formatted_messages: list[dict]) -> set[str]:
"""Collect `tool_use` IDs that were called by `code_execution`.
These blocks cannot have `cache_control` applied per Anthropic API
requirements.
"""
code_execution_tool_ids: set[str] = set()
for message in formatted_messages:
if message.get("role") != "assistant":
continue
content = message.get("content", [])
if not isinstance(content, list):
continue
for block in content:
if not isinstance(block, dict):
continue
if block.get("type") != "tool_use":
continue
caller = block.get("caller")
if isinstance(caller, dict):
caller_type = caller.get("type", "")
if caller_type.startswith("code_execution"):
tool_id = block.get("id")
if tool_id:
code_execution_tool_ids.add(tool_id)
return code_execution_tool_ids
def _is_code_execution_related_block(
block: dict,
code_execution_tool_ids: set[str],
) -> bool:
"""Return whether a content block is related to `code_execution`.
Returns `True` for blocks that should NOT have `cache_control` applied.
"""
if not isinstance(block, dict):
return False
block_type = block.get("type")
if block_type == "tool_use":
caller = block.get("caller")
if isinstance(caller, dict):
caller_type = caller.get("type", "")
if caller_type.startswith("code_execution"):
return True
if block_type == "tool_result":
tool_use_id = block.get("tool_use_id")
if tool_use_id and tool_use_id in code_execution_tool_ids:
return True
return False
def _is_direct_anthropic_llm_type(llm_type: object) -> bool:
"""Return whether an `_llm_type` reaches Claude via the direct Anthropic API.
Only the direct API accepts the top-level `cache_control` request param.
Subclasses that route through other transports (Bedrock, future backends)
override `_llm_type` and must expand `cache_control` kwargs into
block-level breakpoints instead.
Non-string `_llm_type` values return `False` rather than raising, so a
misbehaving subclass falls through to the safer non-direct branch.
"""
return llm_type == "anthropic-chat"
def _apply_cache_control_to_last_eligible_block(
formatted_messages: list[dict],
cache_control: Any,
code_execution_tool_ids: set[str],
) -> bool:
"""Place `cache_control` on the last block eligible for a breakpoint.
Walks messages newest-to-oldest and, within each, blocks newest-to-oldest,
skipping `code_execution`-related blocks (Anthropic rejects breakpoints
there). String message content is promoted to a single text block so the
breakpoint can be attached.
Returns:
`True` if a breakpoint was applied, `False` if every candidate was
`code_execution`-related (caller should warn and drop the kwarg).
"""
for formatted_message in reversed(formatted_messages):
content = formatted_message.get("content")
if isinstance(content, list) and content:
for block in reversed(content):
if not isinstance(block, dict):
continue
if _is_code_execution_related_block(block, code_execution_tool_ids):
continue
block["cache_control"] = cache_control
return True
elif isinstance(content, str):
formatted_message["content"] = [
{
"type": "text",
"text": content,
"cache_control": cache_control,
}
]
return True
return False
class AnthropicContextOverflowError(anthropic.BadRequestError, ContextOverflowError):
"""BadRequestError raised when input exceeds Anthropic's context limit."""
def _handle_anthropic_bad_request(e: anthropic.BadRequestError) -> None:
"""Handle Anthropic BadRequestError."""
if "prompt is too long" in e.message:
raise AnthropicContextOverflowError(
message=e.message, response=e.response, body=e.body
) from e
if ("messages: at least one message is required") in e.message:
message = "Received only system message(s). "
warnings.warn(message, stacklevel=2)
raise e
raise
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`.
"""
anthropic_api_key: SecretStr = Field(
alias="api_key",
default_factory=secret_from_env("ANTHROPIC_API_KEY", default=""),
)
"""Automatically read from env var `ANTHROPIC_API_KEY` if not provided."""
anthropic_proxy: str | None = Field(
default_factory=from_env("ANTHROPIC_PROXY", default=None)
)
"""Proxy to use for the Anthropic clients, will be used for every API call.
If not provided, will attempt to read from the `ANTHROPIC_PROXY` environment
variable.
"""
default_headers: Mapping[str, str] | None = None
"""Headers to pass to the Anthropic clients, will be used for every API call."""
betas: list[str] | None = None
"""List of beta features to enable. If specified, invocations will be routed
through `client.beta.messages.create`.
Example: `#!python betas=["token-efficient-tools-2025-02-19"]`
"""
# Can also be passed in w/ model_kwargs, but having it as a param makes better devx
#
# Precedence order:
# 1. Call-time kwargs (e.g., llm.invoke(..., betas=[...]))
# 2. model_kwargs (e.g., ChatAnthropic(model_kwargs={"betas": [...]}))
# 3. Direct parameter (e.g., ChatAnthropic(betas=[...]))
model_kwargs: dict[str, Any] = Field(default_factory=dict)
streaming: bool = False
"""Whether to use streaming or not."""
stream_usage: bool = True
"""Whether to include usage metadata in streaming output.
If `True`, additional message chunks will be generated during the stream including
usage metadata.
"""
thinking: dict[str, Any] | None = Field(default=None)
"""Parameters for Claude reasoning.
Examples:
- `#!python {"type": "enabled", "budget_tokens": 10_000}` (pre-4.7 models)
- `#!python {"type": "adaptive"}` (Opus 4.6+)
- `#!python {"type": "adaptive", "display": "summarized"}` (Opus 4.7+)
!!! note "Claude Opus 4.7"
`budget_tokens` is removed on Opus 4.7 — use `{"type": "adaptive"}`
with `output_config.effort` to control reasoning effort. Set `display`
to `"summarized"` to receive summarized reasoning in the response
(default is `"omitted"`).
"""
output_config: dict[str, Any] | None = None
"""Configuration options for the model's output.
Supports the following keys:
- `effort`: Controls how many tokens Claude uses when responding.
One of `"max"`, `"xhigh"`, `"high"`, `"medium"`, or `"low"`.
- `format`: Structured output format configuration (typically set via
`with_structured_output`).
- `task_budget`: Advisory token budget for an agentic loop (beta).
E.g., `#!python {"type": "tokens", "total": 128_000}`.
Example:
.. code-block:: python
ChatAnthropic(
model="claude-opus-4-7",
output_config={
"effort": "xhigh",
"task_budget": {"type": "tokens", "total": 128_000},
},
)
See Anthropic docs on
[extended output](https://platform.claude.com/docs/en/api/go/beta/messages/create).
"""
effort: Literal["max", "xhigh", "high", "medium", "low"] | None = None
"""Convenience shorthand for `output_config.effort`.
When set, this value takes precedence over any `effort` key inside
`output_config`.
Example: `effort="medium"`
!!! note
Setting `effort` to `'high'` produces exactly the same behavior as omitting the
parameter altogether.
"""
mcp_servers: list[dict[str, Any]] | None = None
"""List of MCP servers to use for the request.
Example: `#!python mcp_servers=[{"type": "url", "url": "https://mcp.example.com/mcp",
"name": "example-mcp"}]`
"""
context_management: dict[str, Any] | None = None
"""Configuration for
[context management](https://platform.claude.com/docs/en/build-with-claude/context-editing).
"""
reuse_last_container: bool | None = None
"""Automatically reuse container from most recent response (code execution).
When using the built-in
[code execution tool](https://docs.langchain.com/oss/python/integrations/chat/anthropic#code-execution),
model responses will include container metadata. Set `reuse_last_container=True`
to automatically reuse the container from the most recent response for subsequent
invocations.
"""
inference_geo: str | None = None
"""Controls where model inference runs. See Anthropic's
[data residency](https://platform.claude.com/docs/en/build-with-claude/data-residency)
docs for more information.
"""
@property
def _llm_type(self) -> str:
"""Return type of chat model."""
return "anthropic-chat"
@property
def lc_secrets(self) -> dict[str, str]:
"""Return a mapping of secret keys to environment variables."""
return {
"anthropic_api_key": "ANTHROPIC_API_KEY",
"mcp_servers": "ANTHROPIC_MCP_SERVERS",
}
@classmethod
def is_lc_serializable(cls) -> bool:
"""Whether the class is serializable in langchain."""
return True
@classmethod
def get_lc_namespace(cls) -> list[str]:
"""Get the namespace of the LangChain object.
Returns:
`["langchain", "chat_models", "anthropic"]`
"""
return ["langchain", "chat_models", "anthropic"]
@property
def _identifying_params(self) -> dict[str, Any]:
"""Get the identifying parameters."""
return {
"model": self.model,
"max_tokens": self.max_tokens,
"temperature": self.temperature,
"top_k": self.top_k,
"top_p": self.top_p,
"model_kwargs": self.model_kwargs,
"streaming": self.streaming,
"max_retries": self.max_retries,
"default_request_timeout": self.default_request_timeout,
"thinking": self.thinking,
"output_config": self.output_config,
}
def _get_ls_params(
self,
stop: list[str] | None = None,
**kwargs: Any,
) -> LangSmithParams:
"""Get standard params for tracing."""
params = self._get_invocation_params(stop=stop, **kwargs)
ls_params = LangSmithParams(
ls_provider="anthropic",
ls_model_name=params.get("model", self.model),
ls_model_type="chat",
ls_temperature=params.get("temperature", self.temperature),
)
if ls_max_tokens := params.get("max_tokens", self.max_tokens):
ls_params["ls_max_tokens"] = ls_max_tokens
if ls_stop := stop or params.get("stop", None):
ls_params["ls_stop"] = ls_stop
return ls_params
@model_validator(mode="before")
@classmethod
def set_default_max_tokens(cls, values: dict[str, Any]) -> Any:
"""Set default `max_tokens` from model profile with fallback."""
if values.get("max_tokens") is None:
model = values.get("model") or values.get("model_name")
profile = _get_default_model_profile(model) if model else {}
values["max_tokens"] = profile.get(
"max_output_tokens", _FALLBACK_MAX_OUTPUT_TOKENS
)
return values
@model_validator(mode="before")
@classmethod
def build_extra(cls, values: dict) -> Any:
"""Build model kwargs."""
all_required_field_names = get_pydantic_field_names(cls)
return _build_model_kwargs(values, all_required_field_names)
def _resolve_model_profile(self) -> ModelProfile | None:
profile = _get_default_model_profile(self.model) or None
if profile is not None and self.betas and "context-1m-2025-08-07" in self.betas:
profile["max_input_tokens"] = 1_000_000
return profile
@cached_property
def _client_params(self) -> dict[str, Any]:
# Merge User-Agent with user-provided headers (user headers take precedence)
default_headers = {"User-Agent": _USER_AGENT}
if self.default_headers:
default_headers.update(self.default_headers)
client_params: dict[str, Any] = {
"api_key": self.anthropic_api_key.get_secret_value(),
"base_url": self.anthropic_api_url,
"max_retries": self.max_retries,
"default_headers": default_headers,
}
# value <= 0 indicates the param should be ignored. None is a meaningful value
# for Anthropic client and treated differently than not specifying the param at
# all.
if self.default_request_timeout is None or self.default_request_timeout > 0:
client_params["timeout"] = self.default_request_timeout
return client_params
@cached_property
def _client(self) -> anthropic.Client:
client_params = self._client_params
http_client_params = {"base_url": client_params["base_url"]}
if "timeout" in client_params:
http_client_params["timeout"] = client_params["timeout"]
if self.anthropic_proxy:
http_client_params["anthropic_proxy"] = self.anthropic_proxy
http_client = _get_default_httpx_client(**http_client_params)
params = {
**client_params,
"http_client": http_client,
}
return anthropic.Client(**params)
@cached_property
def _async_client(self) -> anthropic.AsyncClient:
client_params = self._client_params
http_client_params = {"base_url": client_params["base_url"]}
if "timeout" in client_params:
http_client_params["timeout"] = client_params["timeout"]
if self.anthropic_proxy:
http_client_params["anthropic_proxy"] = self.anthropic_proxy
http_client = _get_default_async_httpx_client(**http_client_params)
params = {
**client_params,
"http_client": http_client,
}
return anthropic.AsyncClient(**params)
def _get_request_payload(
self,
input_: LanguageModelInput,
*,
stop: list[str] | None = None,
**kwargs: dict,
) -> dict:
"""Get the request payload for the Anthropic API."""
messages = self._convert_input(input_).to_messages()
for idx, message in enumerate(messages):
# Translate v1 content
if (
isinstance(message, AIMessage)
and message.response_metadata.get("output_version") == "v1"
):
tcs: list[types.ToolCall] = [
{
"type": "tool_call",
"name": tool_call["name"],
"args": tool_call["args"],
"id": tool_call.get("id"),
}
for tool_call in message.tool_calls
]
messages[idx] = message.model_copy(
update={
"content": _convert_from_v1_to_anthropic(
cast(list[types.ContentBlock], message.content),
tcs,
message.response_metadata.get("model_provider"),
)
}
)
system, formatted_messages = _format_messages(messages)
# Only the direct Anthropic API accepts top-level `cache_control`.
# Subclasses that route through other transports (e.g. Bedrock) expand
# `cache_control` kwargs into block-level breakpoints, the only form
# those transports accept.
if not _is_direct_anthropic_llm_type(getattr(self, "_llm_type", None)):
cache_control = kwargs.pop("cache_control", None)
# Empty `formatted_messages` has nothing to attach a breakpoint to;
# skip silently. The warning below is reserved for the surprising
# case where messages exist but every candidate block is ineligible.
if cache_control and formatted_messages:
code_execution_tool_ids = _collect_code_execution_tool_ids(
formatted_messages
)
applied = _apply_cache_control_to_last_eligible_block(
formatted_messages, cache_control, code_execution_tool_ids
)
if not applied:
warnings.warn(
"`cache_control` kwarg was dropped: no eligible "
"content block found (all candidates are "
"`code_execution`-related, which Anthropic forbids "
"breakpoints on).",
UserWarning,
stacklevel=2,
)
payload = {
"model": self.model,
"max_tokens": self.max_tokens,
"messages": formatted_messages,
"temperature": self.temperature,
"top_k": self.top_k,
"top_p": self.top_p,
"stop_sequences": stop or self.stop_sequences,
"betas": self.betas,
"context_management": self.context_management,
"mcp_servers": self.mcp_servers,
"system": system,
**self.model_kwargs,
**kwargs,
}
if self.thinking is not None:
payload["thinking"] = self.thinking
if self.inference_geo is not None:
payload["inference_geo"] = self.inference_geo
# Handle output_config and effort parameter
# Priority: self.effort > kwargs output_config > self.output_config
output_config: dict[str, Any] = {}
if self.output_config:
output_config.update(self.output_config)
payload_oc = payload.get("output_config")
if isinstance(payload_oc, dict):
output_config.update(payload_oc)
if self.effort:
output_config["effort"] = self.effort
if output_config:
payload["output_config"] = output_config
if "response_format" in payload:
# response_format present when using agents.create_agent's ProviderStrategy
# ---
# ProviderStrategy converts to OpenAI-style format, which passes kwargs to
# ChatAnthropic, ending up in our payload
response_format = payload.pop("response_format")
if (
isinstance(response_format, dict)
and response_format.get("type") == "json_schema"
and "schema" in response_format.get("json_schema", {})
):
response_format = cast(dict, response_format["json_schema"]["schema"])
# Convert OpenAI-style response_format to Anthropic's output_config.format
output_config = payload.setdefault("output_config", {})
output_config["format"] = _convert_to_anthropic_output_config_format(
response_format
)
# Handle deprecated output_format parameter for backward compatibility
if "output_format" in payload:
warnings.warn(
"The 'output_format' parameter is deprecated and will be removed in a "
"future version. Use 'output_config={\"format\": ...}' instead.",
DeprecationWarning,
stacklevel=2,
)
output_config = payload.setdefault("output_config", {})
output_config["format"] = payload.pop("output_format")
if self.reuse_last_container:
# Check for most recent AIMessage with container set in response_metadata
# and set as a top-level param on the request
for message in reversed(messages):
if (
isinstance(message, AIMessage)
and (container := message.response_metadata.get("container"))
and isinstance(container, dict)
and (container_id := container.get("id"))
):
payload["container"] = container_id
break
# Note: Beta headers are no longer required for structured outputs
# (output_config.format or strict tool use) as they are now generally available
if "tools" in payload and isinstance(payload["tools"], list):
# Auto-append required betas for specific tool types and input_examples
has_input_examples = False
for tool in payload["tools"]:
if isinstance(tool, dict):
tool_type = tool.get("type")
if tool_type and tool_type in _TOOL_TYPE_TO_BETA:
required_beta = _TOOL_TYPE_TO_BETA[tool_type]
if payload["betas"]:
if required_beta not in payload["betas"]:
payload["betas"] = [
*payload["betas"],
required_beta,
]
else:
payload["betas"] = [required_beta]
# Check for input_examples
if tool.get("input_examples"):
has_input_examples = True
# Auto-append header for input_examples
if has_input_examples:
required_beta = "advanced-tool-use-2025-11-20"
if payload["betas"]:
if required_beta not in payload["betas"]:
payload["betas"] = [*payload["betas"], required_beta]
else:
payload["betas"] = [required_beta]
# Auto-append required beta for mcp_servers
if payload.get("mcp_servers"):
required_beta = "mcp-client-2025-11-20"
if payload["betas"]:
# Append to existing betas if not already present
if required_beta not in payload["betas"]:
payload["betas"] = [*payload["betas"], required_beta]
else:
payload["betas"] = [required_beta]
# Auto-append required beta for task_budget
resolved_oc = payload.get("output_config")
if isinstance(resolved_oc, dict) and resolved_oc.get("task_budget"):
required_beta = "task-budgets-2026-03-13"
if payload.get("betas"):
if required_beta not in payload["betas"]:
payload["betas"] = [*payload["betas"], required_beta]
else:
payload["betas"] = [required_beta]
return {k: v for k, v in payload.items() if v is not None}
def _create(self, payload: dict) -> Any:
if "betas" in payload:
return self._client.beta.messages.create(**payload)
return self._client.messages.create(**payload)
async def _acreate(self, payload: dict) -> Any:
if "betas" in payload:
return await self._async_client.beta.messages.create(**payload)
return await self._async_client.messages.create(**payload)
def _stream(
self,
messages: list[BaseMessage],
stop: list[str] | None = None,
run_manager: CallbackManagerForLLMRun | None = None,
*,
stream_usage: bool | None = None,
**kwargs: Any,
) -> Iterator[ChatGenerationChunk]:
if stream_usage is None:
stream_usage = self.stream_usage
kwargs["stream"] = True
payload = self._get_request_payload(messages, stop=stop, **kwargs)
try:
stream = self._create(payload)
coerce_content_to_string = (
not _tools_in_params(payload)
and not _documents_in_params(payload)
and not _thinking_in_params(payload)
and not _compact_in_params(payload)
)
block_start_event = None
for event in stream:
msg, block_start_event = self._make_message_chunk_from_anthropic_event(
event,
stream_usage=stream_usage,
coerce_content_to_string=coerce_content_to_string,
block_start_event=block_start_event,
)
if msg is not None:
chunk = ChatGenerationChunk(message=msg)
if run_manager and isinstance(msg.content, str):
run_manager.on_llm_new_token(msg.content, chunk=chunk)
yield chunk
except anthropic.BadRequestError as e:
_handle_anthropic_bad_request(e)
async def _astream(
self,
messages: list[BaseMessage],
stop: list[str] | None = None,
run_manager: AsyncCallbackManagerForLLMRun | None = None,
*,
stream_usage: bool | None = None,
**kwargs: Any,
) -> AsyncIterator[ChatGenerationChunk]:
if stream_usage is None:
stream_usage = self.stream_usage
kwargs["stream"] = True
payload = self._get_request_payload(messages, stop=stop, **kwargs)
try:
stream = await self._acreate(payload)
coerce_content_to_string = (
not _tools_in_params(payload)
and not _documents_in_params(payload)
and not _thinking_in_params(payload)
and not _compact_in_params(payload)
)
block_start_event = None
async for event in stream:
msg, block_start_event = self._make_message_chunk_from_anthropic_event(
event,
stream_usage=stream_usage,
coerce_content_to_string=coerce_content_to_string,
block_start_event=block_start_event,
)
if msg is not None:
chunk = ChatGenerationChunk(message=msg)
if run_manager and isinstance(msg.content, str):
await run_manager.on_llm_new_token(msg.content, chunk=chunk)
yield chunk
except anthropic.BadRequestError as e:
_handle_anthropic_bad_request(e)
def _make_message_chunk_from_anthropic_event(
self,
event: anthropic.types.RawMessageStreamEvent,
*,
stream_usage: bool = True,
coerce_content_to_string: bool,
block_start_event: anthropic.types.RawMessageStreamEvent | None = None,
) -> tuple[AIMessageChunk | None, anthropic.types.RawMessageStreamEvent | None]:
"""Convert Anthropic streaming event to `AIMessageChunk`.
Args:
event: Raw streaming event from Anthropic SDK
stream_usage: Whether to include usage metadata in the output chunks.
coerce_content_to_string: Whether to convert structured content to plain
text strings.
When `True`, only text content is preserved; when `False`, structured
content like tool calls and citations are maintained.
block_start_event: Previous content block start event, used for tracking
tool use blocks and maintaining context across related events.
Returns:
Tuple with
- `AIMessageChunk`: Converted message chunk with appropriate content and
metadata, or `None` if the event doesn't produce a chunk
- `RawMessageStreamEvent`: Updated `block_start_event` for tracking
content blocks across sequential events, or `None` if not applicable
Note:
Not all Anthropic events result in message chunks. Events like internal
state changes return `None` for the message chunk while potentially
updating the `block_start_event` for context tracking.
"""
message_chunk: AIMessageChunk | None = None
# Reference: Anthropic SDK streaming implementation
# https://github.com/anthropics/anthropic-sdk-python/blob/main/src/anthropic/lib/streaming/_messages.py # noqa: E501
if event.type == "message_start" and stream_usage:
# Capture model name, but don't include usage_metadata yet
# as it will be properly reported in message_delta with complete info
if hasattr(event.message, "model"):
response_metadata: dict[str, Any] = {"model_name": event.message.model}
else:
response_metadata = {}
message_chunk = AIMessageChunk(
content="" if coerce_content_to_string else [],
response_metadata=response_metadata,
)
elif (
event.type == "content_block_start"
and event.content_block is not None
and (
"tool_result" in event.content_block.type
or "tool_use" in event.content_block.type
or "document" in event.content_block.type
or "redacted_thinking" in event.content_block.type
)
):
if coerce_content_to_string:
warnings.warn("Received unexpected tool content block.", stacklevel=2)
content_block = event.content_block.model_dump()
if "caller" in content_block and content_block["caller"] is None:
content_block.pop("caller")
content_block["index"] = event.index
if event.content_block.type == "tool_use":
if (
parsed_args := getattr(event.content_block, "input", None)
) and isinstance(parsed_args, dict):
# In some cases parsed args are represented in start event, with no
# following input_json_delta events
args = json.dumps(parsed_args)
else:
args = ""
tool_call_chunk = create_tool_call_chunk(
index=event.index,
id=event.content_block.id,
name=event.content_block.name,
args=args,
)
tool_call_chunks = [tool_call_chunk]
else:
tool_call_chunks = []
message_chunk = AIMessageChunk(
content=[content_block],
tool_call_chunks=tool_call_chunks,
)
block_start_event = event
# Process incremental content updates
elif event.type == "content_block_delta":
# Text and citation deltas (incremental text content)
if event.delta.type in ("text_delta", "citations_delta"):
if coerce_content_to_string and hasattr(event.delta, "text"):
text = getattr(event.delta, "text", "")
message_chunk = AIMessageChunk(content=text)
else:
content_block = event.delta.model_dump()
content_block["index"] = event.index
# All citation deltas are part of a text block
content_block["type"] = "text"
if "citation" in content_block:
# Assign citations to a list if present
content_block["citations"] = [content_block.pop("citation")]
message_chunk = AIMessageChunk(content=[content_block])
# Reasoning
elif event.delta.type in {"thinking_delta", "signature_delta"}:
content_block = event.delta.model_dump()
content_block["index"] = event.index
content_block["type"] = "thinking"
message_chunk = AIMessageChunk(content=[content_block])
# Tool input JSON (streaming tool arguments)
elif event.delta.type == "input_json_delta":
content_block = event.delta.model_dump()
content_block["index"] = event.index
start_event_block = (
getattr(block_start_event, "content_block", None)
if block_start_event
else None
)
if (
start_event_block is not None
and getattr(start_event_block, "type", None) == "tool_use"
):
tool_call_chunk = create_tool_call_chunk(
index=event.index,
id=None,
name=None,
args=event.delta.partial_json,
)
tool_call_chunks = [tool_call_chunk]
else:
tool_call_chunks = []
message_chunk = AIMessageChunk(
content=[content_block],
tool_call_chunks=tool_call_chunks,
)
# Compaction block
elif event.delta.type == "compaction_delta":
content_block = event.delta.model_dump()
content_block["index"] = event.index
content_block["type"] = "compaction"
if (
"encrypted_content" in content_block
and content_block["encrypted_content"] is None
):
content_block.pop("encrypted_content")
message_chunk = AIMessageChunk(content=[content_block])
# Process final usage metadata and completion info
elif event.type == "message_delta" and stream_usage:
usage_metadata = _create_usage_metadata(event.usage)
response_metadata = {
"stop_reason": event.delta.stop_reason,
"stop_sequence": event.delta.stop_sequence,
}
if context_management := getattr(event, "context_management", None):
response_metadata["context_management"] = (
context_management.model_dump()
)
message_delta = getattr(event, "delta", None)
if message_delta and (
container := getattr(message_delta, "container", None)
):
response_metadata["container"] = container.model_dump(mode="json")
message_chunk = AIMessageChunk(
content="" if coerce_content_to_string else [],
usage_metadata=usage_metadata,
response_metadata=response_metadata,
)
if message_chunk.response_metadata.get("stop_reason"):
# Mark final Anthropic stream chunk
message_chunk.chunk_position = "last"
# Unhandled event types (e.g., `content_block_stop`, `ping` events)
# https://platform.claude.com/docs/en/build-with-claude/streaming#other-events
else:
pass
if message_chunk:
message_chunk.response_metadata["model_provider"] = "anthropic"
return message_chunk, block_start_event
def _format_output(self, data: Any, **kwargs: Any) -> ChatResult:
"""Format the output from the Anthropic API to LC."""
data_dict = data.model_dump()
content = data_dict["content"]
# Remove citations if they are None - introduced in anthropic sdk 0.45
for block in content:
if isinstance(block, dict):
if "citations" in block and block["citations"] is None:
block.pop("citations")
if "caller" in block and block["caller"] is None:
block.pop("caller")
if "encrypted_content" in block and block["encrypted_content"] is None:
block.pop("encrypted_content")
if (
block.get("type") == "thinking"
and "text" in block
and block["text"] is None
):
block.pop("text")
llm_output = {
k: v for k, v in data_dict.items() if k not in ("content", "role", "type")
}
if (
(container := llm_output.get("container"))
and isinstance(container, dict)
and (expires_at := container.get("expires_at"))
and isinstance(expires_at, datetime.datetime)
):
# TODO: dump all `data` with `mode="json"`
llm_output["container"]["expires_at"] = expires_at.isoformat()
response_metadata = {"model_provider": "anthropic"}
if "model" in llm_output and "model_name" not in llm_output:
llm_output["model_name"] = llm_output["model"]
if (
len(content) == 1
and content[0]["type"] == "text"
and not content[0].get("citations")
):
msg = AIMessage(
content=content[0]["text"], response_metadata=response_metadata
)
elif any(block["type"] == "tool_use" for block in content):
tool_calls = extract_tool_calls(content)
msg = AIMessage(
content=content,
tool_calls=tool_calls,
response_metadata=response_metadata,
)
else:
msg = AIMessage(content=content, response_metadata=response_metadata)
msg.usage_metadata = _create_usage_metadata(data.usage)
return ChatResult(
generations=[ChatGeneration(message=msg)],
llm_output=llm_output,
)
def _generate(
self,
messages: list[BaseMessage],
stop: list[str] | None = None,
run_manager: CallbackManagerForLLMRun | None = None,
**kwargs: Any,
) -> ChatResult:
payload = self._get_request_payload(messages, stop=stop, **kwargs)
try:
data = self._create(payload)
except anthropic.BadRequestError as e:
_handle_anthropic_bad_request(e)
return self._format_output(data, **kwargs)
async def _agenerate(
self,
messages: list[BaseMessage],
stop: list[str] | None = None,
run_manager: AsyncCallbackManagerForLLMRun | None = None,
**kwargs: Any,
) -> ChatResult:
payload = self._get_request_payload(messages, stop=stop, **kwargs)
try:
data = await self._acreate(payload)
except anthropic.BadRequestError as e:
_handle_anthropic_bad_request(e)
return self._format_output(data, **kwargs)
def _get_llm_for_structured_output_when_thinking_is_enabled(
self,
schema: dict | type,
formatted_tool: AnthropicTool,
) -> Runnable[LanguageModelInput, BaseMessage]:
thinking_admonition = (
"You are attempting to use structured output via forced tool calling, "
"which is not guaranteed when `thinking` is enabled. This method will "
"raise an OutputParserException if tool calls are not generated. Consider "
"disabling `thinking` or adjust your prompt to ensure the tool is called."
)
warnings.warn(thinking_admonition, stacklevel=2)
llm = self.bind_tools(
[schema],
# We don't specify tool_choice here since the API will reject attempts to
# force tool calls when thinking=true
ls_structured_output_format={
"kwargs": {"method": "function_calling"},
"schema": formatted_tool,
},
)
def _raise_if_no_tool_calls(message: AIMessage) -> AIMessage:
if not message.tool_calls:
raise OutputParserException(thinking_admonition)
return message
return llm | _raise_if_no_tool_calls
def bind_tools(
self,
tools: Sequence[Mapping[str, Any] | type | Callable | BaseTool],
*,
tool_choice: dict[str, str] | str | None = None,
parallel_tool_calls: bool | None = None,
strict: bool | None = None,
**kwargs: Any,
) -> Runnable[LanguageModelInput, AIMessage]:
r"""Bind tool-like objects to `ChatAnthropic`.
Args:
tools: A list of tool definitions to bind to this chat model.
Supports Anthropic format tool schemas and any tool definition handled
by [`convert_to_openai_tool`][langchain_core.utils.function_calling.convert_to_openai_tool].
tool_choice: Which tool to require the model to call. Options are:
- Name of the tool as a string or as dict `{"type": "tool", "name": "<<tool_name>>"}`: calls corresponding tool
- `'auto'`, `{"type: "auto"}`, or `None`: automatically selects a tool (including no tool)
- `'any'` or `{"type: "any"}`: force at least one tool to be called
parallel_tool_calls: Set to `False` to disable parallel tool use.
Defaults to `None` (no specification, which allows parallel tool use).
!!! version-added "Added in `langchain-anthropic` 0.3.2"
strict: If `True`, Claude's schema adherence is applied to tool calls.
See the [docs](https://docs.langchain.com/oss/python/integrations/chat/anthropic#strict-tool-use) for more info.
kwargs: Any additional parameters are passed directly to `bind`.
Example:
```python
from langchain_anthropic import ChatAnthropic
from pydantic import BaseModel, Field
class GetWeather(BaseModel):
'''Get the current weather in a given location'''
location: str = Field(..., description="The city and state, e.g. San Francisco, CA")
class GetPrice(BaseModel):
'''Get the price of a specific product.'''
product: str = Field(..., description="The product to look up.")
model = ChatAnthropic(model="claude-sonnet-4-5-20250929", temperature=0)
model_with_tools = model.bind_tools([GetWeather, GetPrice])
model_with_tools.invoke(
"What is the weather like in San Francisco",
)
# -> AIMessage(
# content=[
# {'text': '<thinking>\nBased on the user\'s question, the relevant function to call is GetWeather, which requires the "location" parameter.\n\nThe user has directly specified the location as "San Francisco". Since San Francisco is a well known city, I can reasonably infer they mean San Francisco, CA without needing the state specified.\n\nAll the required parameters are provided, so I can proceed with the API call.\n</thinking>', 'type': 'text'},
# {'text': None, 'type': 'tool_use', 'id': 'toolu_01SCgExKzQ7eqSkMHfygvYuu', 'name': 'GetWeather', 'input': {'location': 'San Francisco, CA'}}
# ],
# response_metadata={'id': 'msg_01GM3zQtoFv8jGQMW7abLnhi', 'model': 'claude-sonnet-4-5-20250929', 'stop_reason': 'tool_use', 'stop_sequence': None, 'usage': {'input_tokens': 487, 'output_tokens': 145}},
# id='run-87b1331e-9251-4a68-acef-f0a018b639cc-0'
# )
```
""" # noqa: E501
# Allows built-in tools either by their:
# - Raw `dict` format
# - Extracting extras["provider_tool_definition"] if provided on a BaseTool
formatted_tools = [
tool
if _is_builtin_tool(tool)
else convert_to_anthropic_tool(tool, strict=strict)
for tool in tools
]
if not tool_choice:
pass
elif isinstance(tool_choice, dict):
kwargs["tool_choice"] = tool_choice
elif isinstance(tool_choice, str) and tool_choice in ("any", "auto"):
kwargs["tool_choice"] = {"type": tool_choice}
elif isinstance(tool_choice, str):
kwargs["tool_choice"] = {"type": "tool", "name": tool_choice}
else:
msg = (
f"Unrecognized 'tool_choice' type {tool_choice=}. Expected dict, "
f"str, or None."
)
raise ValueError(
msg,
)
# Anthropic API rejects forced tool use when thinking is enabled:
# "Thinking may not be enabled when tool_choice forces tool use."
# Drop forced tool_choice and warn, matching the behavior in
# _get_llm_for_structured_output_when_thinking_is_enabled.
if (
self.thinking is not None
and self.thinking.get("type") in ("enabled", "adaptive")
and "tool_choice" in kwargs
and kwargs["tool_choice"].get("type") in ("any", "tool")
):
warnings.warn(
"tool_choice is forced but thinking is enabled. The Anthropic "
"API does not support forced tool use with thinking. "
"Dropping tool_choice to avoid an API error. Tool calls are "
"not guaranteed. Consider disabling thinking or adjusting "
"your prompt to ensure the tool is called.",
stacklevel=2,
)
del kwargs["tool_choice"]
if parallel_tool_calls is not None:
disable_parallel_tool_use = not parallel_tool_calls
if "tool_choice" in kwargs:
kwargs["tool_choice"]["disable_parallel_tool_use"] = (
disable_parallel_tool_use
)
else:
kwargs["tool_choice"] = {
"type": "auto",
"disable_parallel_tool_use": disable_parallel_tool_use,
}
return self.bind(tools=formatted_tools, **kwargs)
def with_structured_output(
self,
schema: dict | type,
*,
include_raw: bool = False,
method: Literal["function_calling", "json_schema"] = "function_calling",
**kwargs: Any,
) -> Runnable[LanguageModelInput, dict | BaseModel]:
"""Model wrapper that returns outputs formatted to match the given schema.
See the [LangChain docs](https://docs.langchain.com/oss/python/integrations/chat/anthropic#structured-output)
for more details and examples.
Args:
schema: The output schema. Can be passed in as:
- An Anthropic tool schema,
- An OpenAI function/tool schema,
- A JSON Schema,
- A `TypedDict` class,
- Or a Pydantic class.
If `schema` is a Pydantic class then the model output will be a
Pydantic instance of that class, and the model-generated fields will be
validated by the Pydantic class. Otherwise the model output will be a
dict and will not be validated.
See `langchain_core.utils.function_calling.convert_to_openai_tool` for
more on how to properly specify types and descriptions of schema fields
when specifying a Pydantic or `TypedDict` class.
include_raw:
If `False` then only the parsed structured output is returned.
If an error occurs during model output parsing it will be raised.
If `True` then both the raw model response (a `BaseMessage`) and the
parsed model response will be returned.
If an error occurs during output parsing it will be caught and returned
as well.
The final output is always a `dict` with keys `'raw'`, `'parsed'`, and
`'parsing_error'`.
method: The structured output method to use. Options are:
- `'function_calling'` (default): Use forced tool calling to get
structured output.
- `'json_schema'`: Use Claude's dedicated
[structured output](https://platform.claude.com/docs/en/build-with-claude/structured-outputs)
feature.
kwargs: Additional keyword arguments are ignored.
Returns:
A `Runnable` that takes same inputs as a
`langchain_core.language_models.chat.BaseChatModel`.
If `include_raw` is `False` and `schema` is a Pydantic class, `Runnable`
outputs an instance of `schema` (i.e., a Pydantic object). Otherwise, if
`include_raw` is `False` then `Runnable` outputs a `dict`.
If `include_raw` is `True`, then `Runnable` outputs a `dict` with keys:
- `'raw'`: `BaseMessage`
- `'parsed'`: `None` if there was a parsing error, otherwise the type
depends on the `schema` as described above.
- `'parsing_error'`: `BaseException | None`
Example:
```python hl_lines="13"
from langchain_anthropic import ChatAnthropic
from pydantic import BaseModel, Field
model = ChatAnthropic(model="claude-sonnet-4-5")
class Movie(BaseModel):
\"\"\"A movie with details.\"\"\"
title: str = Field(..., description="The title of the movie")
year: int = Field(..., description="The year the movie was released")
director: str = Field(..., description="The director of the movie")
rating: float = Field(..., description="The movie's rating out of 10")
model_with_structure = model.with_structured_output(Movie, method="json_schema")
response = model_with_structure.invoke("Provide details about the movie Inception")
print(response)
# -> Movie(title="Inception", year=2010, director="Christopher Nolan", rating=8.8)
```
""" # noqa: E501
if method == "json_mode":
warning_message = (
"Unrecognized structured output method 'json_mode'. Defaulting to "
"'json_schema' method."
)
warnings.warn(warning_message, stacklevel=2)
method = "json_schema"
if method == "function_calling":
formatted_tool = cast(AnthropicTool, convert_to_anthropic_tool(schema))
# The result of convert_to_anthropic_tool for 'method=function_calling' will
# always be an AnthropicTool
tool_name = formatted_tool["name"]
if self.thinking is not None and self.thinking.get("type") in (
"enabled",
"adaptive",
):
llm = self._get_llm_for_structured_output_when_thinking_is_enabled(
schema,
formatted_tool,
)
else:
llm = self.bind_tools(
[schema],
tool_choice=tool_name, # Force tool call
ls_structured_output_format={
"kwargs": {"method": "function_calling"},
"schema": formatted_tool,
},
)
if isinstance(schema, type) and is_basemodel_subclass(schema):
output_parser: OutputParserLike = PydanticToolsParser(
tools=[schema],
first_tool_only=True,
)
else:
output_parser = JsonOutputKeyToolsParser(
key_name=tool_name,
first_tool_only=True,
)
elif method == "json_schema":
llm = self.bind(
output_config={
"format": _convert_to_anthropic_output_config_format(schema)
},
ls_structured_output_format={
"kwargs": {"method": "json_schema"},
"schema": convert_to_openai_tool(schema),
},
)
if isinstance(schema, type) and is_basemodel_subclass(schema):
output_parser = PydanticOutputParser(pydantic_object=schema)
else:
output_parser = JsonOutputParser()
else:
error_message = (
f"Unrecognized structured output method '{method}'. "
f"Expected 'function_calling' or 'json_schema'."
)
raise ValueError(error_message)
if include_raw:
parser_assign = RunnablePassthrough.assign(
parsed=itemgetter("raw") | output_parser,
parsing_error=lambda _: None,
)
parser_none = RunnablePassthrough.assign(parsed=lambda _: None)
parser_with_fallback = parser_assign.with_fallbacks(
[parser_none],
exception_key="parsing_error",
)
return RunnableMap(raw=llm) | parser_with_fallback
return llm | output_parser
def get_num_tokens_from_messages(
self,
messages: list[BaseMessage],
tools: Sequence[dict[str, Any] | type | Callable | BaseTool] | None = None,
**kwargs: Any,
) -> int:
"""Count tokens in a sequence of input messages.
This uses Anthropic's official [token counting API](https://platform.claude.com/docs/en/build-with-claude/token-counting).
Args:
messages: The message inputs to tokenize.
tools: If provided, sequence of `dict`, `BaseModel`, function, or `BaseTool`
objects to be converted to tool schemas.
kwargs: Additional keyword arguments are passed to the Anthropic
`messages.count_tokens` method.
???+ example "Basic usage"
```python
from langchain_anthropic import ChatAnthropic
from langchain_core.messages import HumanMessage, SystemMessage
model = ChatAnthropic(model="claude-sonnet-4-5-20250929")
messages = [
SystemMessage(content="You are a scientist"),
HumanMessage(content="Hello, Claude"),
]
model.get_num_tokens_from_messages(messages)
```
```txt
14
```
??? example "Pass tool schemas"
```python
from langchain_anthropic import ChatAnthropic
from langchain_core.messages import HumanMessage
from langchain_core.tools import tool
model = ChatAnthropic(model="claude-sonnet-4-5-20250929")
@tool(parse_docstring=True)
def get_weather(location: str) -> str:
\"\"\"Get the current weather in a given location
Args:
location: The city and state, e.g. San Francisco, CA
\"\"\"
return "Sunny"
messages = [
HumanMessage(content="What's the weather like in San Francisco?"),
]
model.get_num_tokens_from_messages(messages, tools=[get_weather])
```
```txt
403
```
""" # noqa: D214
formatted_system, formatted_messages = _format_messages(messages)
if isinstance(formatted_system, str):
kwargs["system"] = formatted_system
if tools:
kwargs["tools"] = [convert_to_anthropic_tool(tool) for tool in tools]
if self.context_management is not None:
kwargs["context_management"] = self.context_management
if self.betas is not None:
beta_response = self._client.beta.messages.count_tokens(
betas=self.betas,
model=self.model,
messages=formatted_messages, # type: ignore[arg-type]
**kwargs,
)
return beta_response.input_tokens
response = self._client.messages.count_tokens(
model=self.model,
messages=formatted_messages, # type: ignore[arg-type]
**kwargs,
)
return response.input_tokens
def convert_to_anthropic_tool(
tool: Mapping[str, Any] | type | Callable | BaseTool,
*,
strict: bool | None = None,
) -> AnthropicTool:
"""Convert a tool-like object to an Anthropic tool definition.
Args:
tool: A tool-like object to convert. Can be an Anthropic tool dict,
a Pydantic model, a function, or a `BaseTool`.
strict: If `True`, enables strict schema adherence for the tool.
!!! note
Requires Claude Sonnet 4.5 or Opus 4.1.
Returns:
`AnthropicTool` for custom/user-defined tools
"""
if (
isinstance(tool, BaseTool)
and hasattr(tool, "extras")
and isinstance(tool.extras, dict)
and "provider_tool_definition" in tool.extras
):
# Pass through built-in tool definitions
return tool.extras["provider_tool_definition"] # type: ignore[return-value]
if isinstance(tool, dict) and all(
k in tool for k in ("name", "description", "input_schema")
):
# Anthropic tool format
anthropic_formatted = AnthropicTool(tool) # type: ignore[misc]
else:
oai_formatted = convert_to_openai_tool(tool, strict=strict)["function"]
anthropic_formatted = AnthropicTool(
name=oai_formatted["name"],
input_schema=oai_formatted["parameters"],
)
if "description" in oai_formatted:
anthropic_formatted["description"] = oai_formatted["description"]
if "strict" in oai_formatted and isinstance(strict, bool):
anthropic_formatted["strict"] = oai_formatted["strict"]
# Select params from tool.extras
if (
isinstance(tool, BaseTool)
and hasattr(tool, "extras")
and isinstance(tool.extras, dict)
):
for key, value in tool.extras.items():
if key in _ANTHROPIC_EXTRA_FIELDS:
# all are populated top-level
anthropic_formatted[key] = value # type: ignore[literal-required]
return anthropic_formatted
def _tools_in_params(params: dict) -> bool:
return (
"tools" in params
or ("extra_body" in params and params["extra_body"].get("tools"))
or "mcp_servers" in params
)
def _thinking_in_params(params: dict) -> bool:
return params.get("thinking", {}).get("type") in ("enabled", "adaptive")
def _documents_in_params(params: dict) -> bool:
for message in params.get("messages", []):
if isinstance(message.get("content"), list):
for block in message["content"]:
if (
isinstance(block, dict)
and block.get("type") == "document"
and block.get("citations", {}).get("enabled")
):
return True
return False
def _compact_in_params(params: dict) -> bool:
edits = params.get("context_management", {}).get("edits") or []
return any("compact" in (edit.get("type") or "") for edit in edits)
class _AnthropicToolUse(TypedDict):
type: Literal["tool_use"]
name: str
input: dict
id: str
caller: NotRequired[dict[str, Any]]
def _lc_tool_calls_to_anthropic_tool_use_blocks(
tool_calls: list[ToolCall],
) -> list[_AnthropicToolUse]:
return [
_AnthropicToolUse(
type="tool_use",
name=tool_call["name"],
input=tool_call["args"],
id=cast("str", tool_call["id"]),
)
for tool_call in tool_calls
]
def _convert_to_anthropic_output_config_format(schema: dict | type) -> dict[str, Any]:
"""Convert JSON schema, Pydantic model, or `TypedDict` into `output_config.format`.
See Claude docs on [structured outputs](https://platform.claude.com/docs/en/build-with-claude/structured-outputs).
Args:
schema: A JSON schema dict, Pydantic model class, or TypedDict.
Returns:
A dict with `type` and `schema` keys suitable for `output_config.format`.
"""
from anthropic import transform_schema
is_pydantic_class = isinstance(schema, type) and is_basemodel_subclass(schema)
if is_pydantic_class or isinstance(schema, dict):
json_schema = transform_schema(schema)
else:
# TypedDict
json_schema = transform_schema(convert_to_json_schema(schema))
return {"type": "json_schema", "schema": json_schema}
def _create_usage_metadata(anthropic_usage: BaseModel) -> UsageMetadata:
"""Create LangChain `UsageMetadata` from Anthropic `Usage` data.
Note:
Anthropic's `input_tokens` excludes cached tokens, so we manually add
`cache_read` and `cache_creation` tokens to get the true total.
"""
input_token_details: dict = {
"cache_read": getattr(anthropic_usage, "cache_read_input_tokens", None),
"cache_creation": getattr(anthropic_usage, "cache_creation_input_tokens", None),
}
# Add cache TTL information if provided (5-minute and 1-hour ephemeral cache)
cache_creation = getattr(anthropic_usage, "cache_creation", None)
# Currently just copying over the 5m and 1h keys, but if more are added in the
# future we'll need to expand this tuple
cache_creation_keys = ("ephemeral_5m_input_tokens", "ephemeral_1h_input_tokens")
specific_cache_creation_tokens = 0
if cache_creation:
if isinstance(cache_creation, BaseModel):
cache_creation = cache_creation.model_dump()
for k in cache_creation_keys:
specific_cache_creation_tokens += cache_creation.get(k, 0)
input_token_details[k] = cache_creation.get(k)
if not isinstance(specific_cache_creation_tokens, int):
specific_cache_creation_tokens = 0
if specific_cache_creation_tokens > 0:
# Remove generic key to avoid double counting cache creation tokens
input_token_details["cache_creation"] = 0
# Calculate total input tokens: Anthropic's `input_tokens` excludes cached tokens,
# so we need to add them back to get the true total input token count
input_tokens = (
(getattr(anthropic_usage, "input_tokens", 0) or 0) # Base input tokens
+ (input_token_details["cache_read"] or 0) # Tokens read from cache
+ (
specific_cache_creation_tokens or input_token_details["cache_creation"] or 0
) # Tokens used to create cache
)
output_tokens = getattr(anthropic_usage, "output_tokens", 0) or 0
return UsageMetadata(
input_tokens=input_tokens,
output_tokens=output_tokens,
total_tokens=input_tokens + output_tokens,
input_token_details=InputTokenDetails(
**{k: v for k, v in input_token_details.items() if v is not None},
),
)