Python Streaming

Use streaming when you want text as it arrives instead of waiting for the final message.

Simple text streaming

from anthropic import Anthropic

client = Anthropic()

with client.messages.stream(
    model="claude-sonnet-4-5",
    max_tokens=1024,
    messages=[{"role": "user", "content": "Write a short release note."}],
) as stream:
    for text in stream.text_stream:
        print(text, end="", flush=True)

Get the final message

If you want streaming transport but still need the final structured Message, use the stream helper and then call the SDK method that returns the completed response object for the stream.

When streaming is worth it

chat or terminal UIs
long generations
progress feedback for users
tool use flows where early visibility matters

Practical guidance

Treat streamed events as incremental UI updates.
Keep the final assembled message as the authoritative result.
Long non-streaming requests are more exposed to idle network timeouts than streaming or batches.
If you do not need live tokens, normal messages.create(...) is simpler.

Official references

Streaming guide: https://platform.claude.com/docs/en/build-with-claude/streaming
Python SDK: https://platform.claude.com/docs/en/api/sdks/python

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