Anthropic Python API library
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The Anthropic Python library provides convenient access to the Anthropic REST API from any Python 3.7+
application. It includes type definitions for all request params and response fields,
and offers both synchronous and asynchronous clients powered by httpx.
Documentation
The REST API documentation can be found on docs.anthropic.com. The full API of this library can be found in api.md.
Installation
pip install anthropic
Usage
The full API of this library can be found in api.md.
import os
from anthropic import Anthropic
client = Anthropic(
api_key=os.environ.get("ANTHROPIC_API_KEY"),
)
message = client.messages.create(
max_tokens=1024,
messages=[
{
"role": "user",
"content": "Hello, Claude",
}
],
model="claude-3-opus-20240229",
)
print(message.content)
While you can provide an api_key
keyword argument,
we recommend using python-dotenv
to add ANTHROPIC_API_KEY="my-anthropic-api-key"
to your .env
file
so that your API Key is not stored in source control.
Async usage
Simply import AsyncAnthropic
instead of Anthropic
and use await
with each API call:
import os
import asyncio
from anthropic import AsyncAnthropic
client = AsyncAnthropic(
api_key=os.environ.get("ANTHROPIC_API_KEY"),
)
async def main() -> None:
message = await client.messages.create(
max_tokens=1024,
messages=[
{
"role": "user",
"content": "Hello, Claude",
}
],
model="claude-3-opus-20240229",
)
print(message.content)
asyncio.run(main())
Functionality between the synchronous and asynchronous clients is otherwise identical.
Streaming responses
We provide support for streaming responses using Server Side Events (SSE).
from anthropic import Anthropic
client = Anthropic()
stream = client.messages.create(
max_tokens=1024,
messages=[
{
"role": "user",
"content": "Hello, Claude",
}
],
model="claude-3-opus-20240229",
stream=True,
)
for event in stream:
print(event.type)
The async client uses the exact same interface.
from anthropic import AsyncAnthropic
client = AsyncAnthropic()
stream = await client.messages.create(
max_tokens=1024,
messages=[
{
"role": "user",
"content": "Hello, Claude",
}
],
model="claude-3-opus-20240229",
stream=True,
)
async for event in stream:
print(event.type)
Streaming Helpers
This library provides several conveniences for streaming messages, for example:
import asyncio
from anthropic import AsyncAnthropic
client = AsyncAnthropic()
async def main() -> None:
async with client.messages.stream(
max_tokens=1024,
messages=[
{
"role": "user",
"content": "Say hello there!",
}
],
model="claude-3-opus-20240229",
) as stream:
async for text in stream.text_stream:
print(text, end="", flush=True)
print()
message = await stream.get_final_message()
print(message.to_json())
asyncio.run(main())
Streaming with client.messages.stream(...)
exposes various helpers for your convenience including accumulation & SDK-specific events.
Alternatively, you can use client.messages.create(..., stream=True)
which only returns an async iterable of the events in the stream and thus uses less memory (it does not build up a final message object for you).
Token counting
You can see the exact usage for a given request through the usage
response property, e.g.
message = client.messages.create(...)
message.usage
Tool use
This SDK provides support for tool use, aka function calling. More details can be found in the documentation.
AWS Bedrock
This library also provides support for the Anthropic Bedrock API if you install this library with the bedrock
extra, e.g. pip install -U anthropic[bedrock]
.
You can then import and instantiate a separate AnthropicBedrock
class, the rest of the API is the same.
from anthropic import AnthropicBedrock
client = AnthropicBedrock()
message = client.messages.create(
max_tokens=1024,
messages=[
{
"role": "user",
"content": "Hello!",
}
],
model="anthropic.claude-3-sonnet-20240229-v1:0",
)
print(message)
For a more fully fledged example see examples/bedrock.py
.
Google Vertex
This library also provides support for the Anthropic Vertex API if you install this library with the vertex
extra, e.g. pip install -U anthropic[vertex]
.
You can then import and instantiate a separate AnthropicVertex
/AsyncAnthropicVertex
class, which has the same API as the base Anthropic
/AsyncAnthropic
class.
from anthropic import AnthropicVertex
client = AnthropicVertex()
message = client.messages.create(
model="claude-3-sonnet@20240229",
max_tokens=100,
messages=[
{
"role": "user",
"content": "Hello!",
}
],
)
print(message)
For a more complete example see examples/vertex.py
.
Using types
Nested request parameters are TypedDicts. Responses are Pydantic models which also provide helper methods for things like:
- Serializing back into JSON,
model.to_json()
- Converting to a dictionary,
model.to_dict()
Typed requests and responses provide autocomplete and documentation within your editor. If you would like to see type errors in VS Code to help catch bugs earlier, set python.analysis.typeCheckingMode
to basic
.
Handling errors
When the library is unable to connect to the API (for example, due to network connection problems or a timeout), a subclass of anthropic.APIConnectionError
is raised.
When the API returns a non-success status code (that is, 4xx or 5xx
response), a subclass of anthropic.APIStatusError
is raised, containing status_code
and response
properties.
All errors inherit from anthropic.APIError
.
import anthropic
from anthropic import Anthropic
client = Anthropic()
try:
client.messages.create(
max_tokens=1024,
messages=[
{
"role": "user",
"content": "Hello, Claude",
}
],
model="claude-3-opus-20240229",
)
except anthropic.APIConnectionError as e:
print("The server could not be reached")
print(e.__cause__)
except anthropic.RateLimitError as e:
print("A 429 status code was received; we should back off a bit.")
except anthropic.APIStatusError as e:
print("Another non-200-range status code was received")
print(e.status_code)
print(e.response)
Error codes are as followed:
Status Code | Error Type |
---|
400 | BadRequestError |
401 | AuthenticationError |
403 | PermissionDeniedError |
404 | NotFoundError |
422 | UnprocessableEntityError |
429 | RateLimitError |
>=500 | InternalServerError |
N/A | APIConnectionError |
Retries
Certain errors are automatically retried 2 times by default, with a short exponential backoff.
Connection errors (for example, due to a network connectivity problem), 408 Request Timeout, 409 Conflict,
429 Rate Limit, and >=500 Internal errors are all retried by default.
You can use the max_retries
option to configure or disable retry settings:
from anthropic import Anthropic
client = Anthropic(
max_retries=0,
)
client.with_options(max_retries=5).messages.create(
max_tokens=1024,
messages=[
{
"role": "user",
"content": "Hello, Claude",
}
],
model="claude-3-opus-20240229",
)
Timeouts
By default requests time out after 10 minutes. You can configure this with a timeout
option,
which accepts a float or an httpx.Timeout
object:
from anthropic import Anthropic
client = Anthropic(
timeout=20.0,
)
client = Anthropic(
timeout=httpx.Timeout(60.0, read=5.0, write=10.0, connect=2.0),
)
client.with_options(timeout=5.0).messages.create(
max_tokens=1024,
messages=[
{
"role": "user",
"content": "Hello, Claude",
}
],
model="claude-3-opus-20240229",
)
On timeout, an APITimeoutError
is thrown.
Note that requests that time out are retried twice by default.
We automatically send the anthropic-version
header set to 2023-06-01
.
If you need to, you can override it by setting default headers per-request or on the client object.
Be aware that doing so may result in incorrect types and other unexpected or undefined behavior in the SDK.
from anthropic import Anthropic
client = Anthropic(
default_headers={"anthropic-version": "My-Custom-Value"},
)
Advanced
Logging
We use the standard library logging
module.
You can enable logging by setting the environment variable ANTHROPIC_LOG
to debug
.
$ export ANTHROPIC_LOG=debug
How to tell whether None
means null
or missing
In an API response, a field may be explicitly null
, or missing entirely; in either case, its value is None
in this library. You can differentiate the two cases with .model_fields_set
:
if response.my_field is None:
if 'my_field' not in response.model_fields_set:
print('Got json like {}, without a "my_field" key present at all.')
else:
print('Got json like {"my_field": null}.')
The "raw" Response object can be accessed by prefixing .with_raw_response.
to any HTTP method call, e.g.,
from anthropic import Anthropic
client = Anthropic()
response = client.messages.with_raw_response.create(
max_tokens=1024,
messages=[{
"role": "user",
"content": "Hello, Claude",
}],
model="claude-3-opus-20240229",
)
print(response.headers.get('X-My-Header'))
message = response.parse()
print(message.content)
These methods return an LegacyAPIResponse
object. This is a legacy class as we're changing it slightly in the next major version.
For the sync client this will mostly be the same with the exception
of content
& text
will be methods instead of properties. In the
async client, all methods will be async.
A migration script will be provided & the migration in general should
be smooth.
.with_streaming_response
The above interface eagerly reads the full response body when you make the request, which may not always be what you want.
To stream the response body, use .with_streaming_response
instead, which requires a context manager and only reads the response body once you call .read()
, .text()
, .json()
, .iter_bytes()
, .iter_text()
, .iter_lines()
or .parse()
. In the async client, these are async methods.
As such, .with_streaming_response
methods return a different APIResponse
object, and the async client returns an AsyncAPIResponse
object.
with client.messages.with_streaming_response.create(
max_tokens=1024,
messages=[
{
"role": "user",
"content": "Hello, Claude",
}
],
model="claude-3-opus-20240229",
) as response:
print(response.headers.get("X-My-Header"))
for line in response.iter_lines():
print(line)
The context manager is required so that the response will reliably be closed.
Making custom/undocumented requests
This library is typed for convenient access to the documented API.
If you need to access undocumented endpoints, params, or response properties, the library can still be used.
Undocumented endpoints
To make requests to undocumented endpoints, you can make requests using client.get
, client.post
, and other
http verbs. Options on the client will be respected (such as retries) when making this
request.
import httpx
response = client.post(
"/foo",
cast_to=httpx.Response,
body={"my_param": True},
)
print(response.headers.get("x-foo"))
Undocumented request params
If you want to explicitly send an extra param, you can do so with the extra_query
, extra_body
, and extra_headers
request
options.
Undocumented response properties
To access undocumented response properties, you can access the extra fields like response.unknown_prop
. You
can also get all the extra fields on the Pydantic model as a dict with
response.model_extra
.
Configuring the HTTP client
You can directly override the httpx client to customize it for your use case, including:
- Support for proxies
- Custom transports
- Additional advanced functionality
from anthropic import Anthropic, DefaultHttpxClient
client = Anthropic(
base_url="http://my.test.server.example.com:8083",
http_client=DefaultHttpxClient(
proxies="http://my.test.proxy.example.com",
transport=httpx.HTTPTransport(local_address="0.0.0.0"),
),
)
You can also customize the client on a per-request basis by using with_options()
:
client.with_options(http_client=DefaultHttpxClient(...))
Managing HTTP resources
By default the library closes underlying HTTP connections whenever the client is garbage collected. You can manually close the client using the .close()
method if desired, or with a context manager that closes when exiting.
Versioning
This package generally follows SemVer conventions, though certain backwards-incompatible changes may be released as minor versions:
- Changes that only affect static types, without breaking runtime behavior.
- Changes to library internals which are technically public but not intended or documented for external use. (Please open a GitHub issue to let us know if you are relying on such internals).
- Changes that we do not expect to impact the vast majority of users in practice.
We take backwards-compatibility seriously and work hard to ensure you can rely on a smooth upgrade experience.
We are keen for your feedback; please open an issue with questions, bugs, or suggestions.
Requirements
Python 3.7 or higher.