from __future__ import annotations as _annotations
import os
from dataclasses import dataclass
from typing import TypeAlias, overload
import httpx
from pydantic_ai import ModelProfile
from pydantic_ai.exceptions import UserError
from pydantic_ai.models import cached_async_http_client
from pydantic_ai.profiles.anthropic import anthropic_model_profile
from pydantic_ai.providers import Provider
from .._json_schema import JsonSchema, JsonSchemaTransformer
try:
from anthropic import AsyncAnthropic, AsyncAnthropicBedrock, AsyncAnthropicVertex
except ImportError as _import_error:
raise ImportError(
'Please install the `anthropic` package to use the Anthropic provider, '
'you can use the `anthropic` optional group — `pip install "pydantic-ai-slim[anthropic]"`'
) from _import_error
AsyncAnthropicClient: TypeAlias = AsyncAnthropic | AsyncAnthropicBedrock | AsyncAnthropicVertex
class AnthropicProvider(Provider[AsyncAnthropicClient]):
"""Provider for Anthropic API."""
@property
def name(self) -> str:
return 'anthropic'
@property
def base_url(self) -> str:
return str(self._client.base_url)
@property
def client(self) -> AsyncAnthropicClient:
return self._client
def model_profile(self, model_name: str) -> ModelProfile | None:
profile = anthropic_model_profile(model_name)
return ModelProfile(json_schema_transformer=AnthropicJsonSchemaTransformer).update(profile)
@overload
def __init__(self, *, anthropic_client: AsyncAnthropicClient | None = None) -> None: ...
@overload
def __init__(
self, *, api_key: str | None = None, base_url: str | None = None, http_client: httpx.AsyncClient | None = None
) -> None: ...
def __init__(
self,
*,
api_key: str | None = None,
base_url: str | None = None,
anthropic_client: AsyncAnthropicClient | None = None,
http_client: httpx.AsyncClient | None = None,
) -> None:
"""Create a new Anthropic provider.
Args:
api_key: The API key to use for authentication, if not provided, the `ANTHROPIC_API_KEY` environment variable
will be used if available.
base_url: The base URL to use for the Anthropic API.
anthropic_client: An existing [`AsyncAnthropic`](https://github.com/anthropics/anthropic-sdk-python)
client to use. If provided, the `api_key` and `http_client` arguments will be ignored.
http_client: An existing `httpx.AsyncClient` to use for making HTTP requests.
"""
if anthropic_client is not None:
assert http_client is None, 'Cannot provide both `anthropic_client` and `http_client`'
assert api_key is None, 'Cannot provide both `anthropic_client` and `api_key`'
self._client = anthropic_client
else:
api_key = api_key or os.getenv('ANTHROPIC_API_KEY')
if not api_key:
raise UserError(
'Set the `ANTHROPIC_API_KEY` environment variable or pass it via `AnthropicProvider(api_key=...)`'
'to use the Anthropic provider.'
)
if http_client is not None:
self._client = AsyncAnthropic(api_key=api_key, base_url=base_url, http_client=http_client)
else:
http_client = cached_async_http_client(provider='anthropic')
self._client = AsyncAnthropic(api_key=api_key, base_url=base_url, http_client=http_client)
@dataclass(init=False)
class AnthropicJsonSchemaTransformer(JsonSchemaTransformer):
"""Transforms schemas to the subset supported by Anthropic structured outputs.
Transformation is applied when:
- `NativeOutput` is used as the `output_type` of the Agent
- `strict=True` is set on the `Tool`
The behavior of this transformer differs from the OpenAI one in that it sets `Tool.strict=False` by default when not explicitly set to True.
Example:
```python
from pydantic_ai import Agent
agent = Agent('anthropic:claude-sonnet-4-5')
@agent.tool_plain # -> defaults to strict=False
def my_tool(x: str) -> dict[str, int]:
...
```
Anthropic's SDK `transform_schema()` automatically:
- Adds `additionalProperties: false` to all objects (required by API)
- Removes unsupported constraints (minLength, pattern, etc.)
- Moves removed constraints to description field
- Removes title and $schema fields
"""
def walk(self) -> JsonSchema:
schema = super().walk()
# The caller (pydantic_ai.models._customize_tool_def or _customize_output_object) coalesces
# - output_object.strict = self.is_strict_compatible
# - tool_def.strict = self.is_strict_compatible
# the reason we don't default to `strict=True` is that the transformation could be lossy
# so in order to change the behavior (default to True), we need to come up with logic that will check for lossiness
# https://github.com/pydantic/pydantic-ai/issues/3541
self.is_strict_compatible = self.strict is True # not compatible when strict is False/None
if self.strict is True:
from anthropic import transform_schema
return transform_schema(schema)
else:
return schema
def transform(self, schema: JsonSchema) -> JsonSchema:
schema.pop('title', None)
schema.pop('$schema', None)
return schema