feat(bedrock): add support for stream and tool_runner helpers

[Ashutosh0x]

Summary

This PR adds tool_runner and stream method aliases to both Messages and AsyncMessages classes in the Bedrock beta module.

Motivation

Fixes #1106
Fixes #1120

The tool_runner API (client.beta.messages.tool_runner()) was not available on the AnthropicBedrock or AsyncAnthropicBedrock clients. This creates feature parity for enterprise AWS Bedrock users.

Changes

Added method aliases to src/anthropic/lib/bedrock/_beta_messages.py:

• tool_runner - Automatic tool execution loop
• stream - Streaming message helpers

Note: parse was intentionally excluded as Bedrock doesn't currently support the structured output beta header.

Checklist

• Changes follow existing code patterns
• No breaking changes
• Commit follows conventional format

[karpetrosyan]

I believe Bedrock doesn’t support structured outputs at the moment.
I tried locally and got an error saying the structured output beta header isn’t supported.

[cppntn]

What's the ETA on this? At least the stream part

[Ashutosh0x]

@karpetrosyan good catch! you're right, I'll remove parse and keep only stream + ool_runner which don't need that header. updating the PR now

[Ashutosh0x]

@cppntn working on it now! removing the unsupported parse method and keeping stream + ool_runner. should be ready for review shortly

[Ashutosh0x]

updated! removed parse method, now only stream and ool_runner are included. ready for review

[karpetrosyan]

@karpetrosyan good catch! you're right, I'll remove parse and keep only stream + ool_runner which don't need that header. updating the PR now

Sorry, I mean both tool_runner and stream use parse internally, and without it they won’t work.
Third-party clients don’t really support structured outputs at the moment, so I made this tiny change so they can actually use the parse method.

[karpetrosyan]

I was also thinking about raising a runtime error when output_format or output_config is provided to any methods, but I think we can skip that for better future compatibility, when third parties support structured outputs

[karpetrosyan]

Suggested change

	stream = FirstPartyMessagesAPI.stream
	stream = FirstPartyMessagesAPI.stream
	if TYPE_CHECKING:
	...
	else:
	# parse is used by stream and tool_runner internally
	parse = FirstPartyMessagesAPI.parse

[Ashutosh0x]

Thanks for the suggestion! Done - added the parse method internally while keeping it hidden from type checkers.

[karpetrosyan]

Suggested change

	stream = FirstPartyAsyncMessagesAPI.stream
	stream = FirstPartyAsyncMessagesAPI.stream
	if TYPE_CHECKING:
	...
	else:
	# parse is used by stream and tool_runner internally
	parse = FirstPartyMessagesAPI.parse

[Ashutosh0x]

Applied the same fix here for AsyncMessages - parse is now available internally.

[karpetrosyan]

LGTM!
nit: let’s also fix the PR title, since we’re not adding the parse method to beta messages (at least not publicly). I’d suggest:

'feat(bedrock): add support for stream and tool_runner helpers'

[Ashutosh0x]

Updated the PR title as suggested and verified the fix locally. Both sync and async clients now have the parse method available internally, which resolves the dependency for tool_runner and stream. Ready for review!

[cppntn]

@karpetrosyan @Ashutosh0x what's the ETA on this mastodontic PR?