anthropic

library0.84.0pypypi✓ verified 53d ago

Official Python SDK for the Anthropic API providing access to Claude models. Current version is 0.84.0 (Feb 2026). Releases approximately weekly. Two separate packages exist: anthropic (core SDK) and claude-agent-sdk-python (agent workflows).

llm-agents ai-ml

pip install anthropic

github ↗package ↗homepage ↗

Install & Compatibility

Where this runs

tested against v0.107.1 · pip install

no network on importno background threads

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

glibc

py 3.10

8/10 runs

py 3.11

8/10 runs

py 3.12

8/10 runs

py 3.13

8/10 runs

py 3.9

5/10 runs

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

Anthropic

✓ from anthropic import Anthropic

✗ import anthropic; anthropic.Client(api_key=...)

anthropic.Client is the old pre-0.3 API. Removed. Always use Anthropic() class.

AsyncAnthropic

✓ from anthropic import AsyncAnthropic

✗ import anthropic; anthropic.AsyncClient()

Use AsyncAnthropic for async contexts, not the legacy async client.

Minimal message call using the Anthropic SDK 0.84.x.

from anthropic import Anthropic client = Anthropic() # reads ANTHROPIC_API_KEY from env message = client.messages.create( model='claude-opus-4-6', max_tokens=1024, messages=[ {"role": "user", "content": "Hello, Claude"} ] ) print(message.content[0].text)

Debug

Known issues

breakinganthropic.Client() is removed. Use anthropic.Anthropic() instead.

fix

client = Anthropic(api_key=os.environ.get('ANTHROPIC_API_KEY'))

affects: < 0.3.0

gotchaSDK releases weekly. Pin your version in production or expect frequent behaviour changes.

fix

Pin with anthropic==0.84.0 in requirements.txt

affects: all

gotchamessage.content is a list, not a string. Access text via message.content[0].text.

fix

print(message.content[0].text) not print(message.content)

affects: all

gotchamax_tokens is required. No default value. Omitting raises a validation error.

fix

Always pass max_tokens=1024 or appropriate value

affects: all

deprecatedclaude-agent-sdk-python no longer requires Claude Code to be installed separately. It is bundled.

fix

Remove any separate Claude Code install steps from your setup.

affects: all

breakingThe package `claude-agent-sdk` is not a valid PyPI package and cannot be found. If you are trying to install the main Anthropic SDK, use `anthropic`. If you are looking for an agent-specific SDK, you might be looking for `claude-agent-sdk-python`.

fix

Replace `claude-agent-sdk` with `anthropic` or `claude-agent-sdk-python` in your requirements/install commands.

affects: all

breakingFailed to authenticate due to missing API key. Ensure `api_key` is passed during client initialization or set the `ANTHROPIC_API_KEY` environment variable.

fix

client = Anthropic(api_key=os.environ.get('ANTHROPIC_API_KEY'))

affects: all

Errors

Common errors & fixes

ModuleNotFoundError: No module named 'anthropic'

The 'anthropic' package is not installed in the Python environment.

fix

Install the package using 'pip install anthropic'.

ImportError: cannot import name 'Anthropic' from 'anthropic'

The import statement is incorrect; 'Anthropic' is not a valid import from the 'anthropic' package.

fix

Use 'from anthropic import AnthropicClient' instead.

AttributeError: module 'anthropic' has no attribute 'Anthropic'

The 'Anthropic' class does not exist in the 'anthropic' module.

fix

Instantiate the client with 'client = anthropic.AnthropicClient()'.

TypeError: __init__() missing 1 required positional argument: 'api_key'

The 'AnthropicClient' class requires an 'api_key' argument during initialization.

fix

Initialize with 'client = anthropic.AnthropicClient(api_key="your_api_key")'.

ValueError: Invalid API key provided

The provided API key is incorrect or malformed.

fix

Ensure the API key is correct and properly formatted.

Upgrade

Version history

0.107.1latest on PyPI

Audit

Dependencies

claude-agent-sdkoptionalRequired for multi-agent workflows with Claude. Separate from core anthropic package.

anthropic[bedrock]optionalRequired for AWS Bedrock access.

anthropic[vertex]optionalRequired for Google Vertex AI access.

Agent activity

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Resources

githubhttps://github.com/anthropics/anthropic-sdk-python ↗

packagehttps://pypi.org/project/anthropic/ ↗

homepagehttps://www.anthropic.com ↗