Claude Code with Bedrock broken again (github.com)

Claude Code version 2.1.129 has introduced a regression that causes all requests to AWS Bedrock to fail due to unsupported beta flags included in the request body. The specific error message reports a 400 status code, indicating an invalid beta flag, which arises from the inclusion of the "anthropic_beta" array containing flags that Bedrock does not recognize. This issue is significant as it disrupts the functionality of Claude Code, a tool widely used in the AI/ML community for integrating AI models with cloud services. The problematic flags—such as "interleaved-thinking-2025-05-14" and "tool-search-tool-2025-10-19"—were not present in the previous stable version, 2.1.119, which successfully operated with Bedrock. This regression highlights the importance of consistent version control and thorough testing when implementing new features in software development, particularly in AI applications that rely heavily on cloud services. Users experiencing this issue can temporarily resolve it by downgrading to 2.1.119, where these flags are absent, underscoring the potential operational disruptions caused by seemingly minor changes in code updates.