Feature Request: Add tool_runner support for AnthropicBedrock client

[lingjiekong]

Summary

The tool_runner API (client.beta.messages.tool_runner()) is not available on the AnthropicBedrock and AsyncAnthropicBedrock clients, despite the documentation stating "the rest of the API is the same" for Bedrock.

Current Behavior

from anthropic import AsyncAnthropic, AsyncAnthropicBedrock

# Direct Anthropic API - works ✅
client = AsyncAnthropic(api_key='...')
print(type(client.beta.messages))  
# <class 'anthropic.resources.beta.messages.messages.AsyncMessages'>
print(hasattr(client.beta.messages, 'tool_runner'))  # True ✅

# Bedrock API - missing tool_runner ❌
bedrock_client = AsyncAnthropicBedrock(aws_region='us-west-2')
print(type(bedrock_client.beta.messages))  
# <class 'anthropic.lib.bedrock._beta_messages.AsyncMessages'>
print(hasattr(bedrock_client.beta.messages, 'tool_runner'))  # False ❌

Attempting to use tool_runner on Bedrock results in:

AttributeError: 'AsyncMessages' object has no attribute 'tool_runner'

Expected Behavior

The tool_runner API should be available on AnthropicBedrock and AsyncAnthropicBedrock clients, enabling:

• Automatic tool execution loop
• Client-side compaction control (compaction_control parameter)
• Consistent API surface across direct and Bedrock clients

Available Methods Comparison

Method	AsyncAnthropic	AsyncAnthropicBedrock
create	✅	✅
with_raw_response	✅	✅
with_streaming_response	✅	✅
tool_runner	✅	❌ Missing

Use Case

We're building agentic applications that need:

1. Automatic tool execution loops (what tool_runner provides)
2. Client-side compaction control for long-running agent sessions
3. AWS Bedrock for enterprise deployment (compliance, VPC, etc.)

Currently, we must choose between Bedrock (enterprise requirements) OR tool_runner features - we cannot have both.

Environment

• Python SDK version: 0.75.0
• Python version: 3.11

Workaround

Currently using direct Anthropic API (AsyncAnthropic) instead of Bedrock, but this doesn't meet enterprise deployment requirements.

Related

This is similar to other Bedrock feature gaps:

• Count Tokens for Bedrock #353 - count_tokens not available on Bedrock
• PDF Support for AnthropicBedrock #921 - PDF/document support differences on Bedrock

[lingjiekong]

I've created a PR to address this issue: #1107

The PR adds tool_runner support for the Bedrock client by:

1. Exposing tool_runner - Adding delegation to both Messages and AsyncMessages classes
2. Message sanitization - Stripping Bedrock-unsupported fields (parsed_output, caller) that the tool_runner SDK adds internally
3. Wrapping API methods - create, parse, and stream methods are wrapped to apply sanitization transparently

This has been tested with:

• Compaction control (token_threshold: 20000)
• Automatic tool execution loops
• Both sync and async clients

Would love to get feedback from the maintainers on this approach!