Rename .stream()/.stream_async()'s content parameter to stream

[cpsievert]

Breaking change to align the API for streaming content objects with tidyverse/ellmer#494.

Before this change, to access tool request/result objects in a stream, it was:

chat.stream(content="all")

Now it's

chat.stream(stream="content")

UPDATE: Now that I think through this naming change a bit more, I'm not convinced it's an improvement. With stream="content", it could make one wonder what chat.stream() is doing -- is it streaming something other than content? From that perspective, I like content="all" better -- it better implies that you're gaining access to additional content, which is the main point of the parameter existing.

cc @gadenbuie

[Copilot]

Pull Request Overview

This PR updates the .stream() and .stream_async() methods to rename their content parameter to stream, align internal flags, and update related tests and documentation.

• Rename content → stream in signatures, docstrings, and internal calls
• Map new stream values to internal yield_content flags
• Update tests and changelog for the breaking change

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
tests/conftest.py	Updated test call from content="all" to stream="content"
chatlas/_chat.py	Renamed content params to stream in .stream() methods, added yield_content mapping, and refreshed docblocks
CHANGELOG.md	Added breaking change entry for renaming content → stream

Comments suppressed due to low confidence (1)

CHANGELOG.md:25

• The changelog entry has empty parentheses at the end; please include the relevant PR or issue number (e.g., (#494)).

* The `.stream()`/`.stream_async()` method's `content` parameter was renamed to `stream`. Set `stream` to "content" to gain access to tool request/result content objects. ()

[gadenbuie]

With stream="content", it could make one wonder what chat.stream() is doing -- is it streaming something other than content? From that perspective, I like content="all" better -- it better implies that you're gaining access to additional content, which is the main point of the parameter existing.

The distinction is more about the return type. stream="text" streams text and everything yielded by the generator is a string. When stream="content", everything yielded by the generator is a Content instance. The fact that stream="content" includes tool requests and results is a consequence of those items not having a text representation. (In theory, we could decide to yield a standard text representation for stream="text".)

Anyway, I agree the naming is confusing – lots of things could be content – but the contract of always yielding Content makes it worth using this term here.