Claude Code 2.1.229: Keep Vertex and Bedrock Gateway Streams Alive

Claude Code version 2.1.229 introduces a fix to keep Vertex and Bedrock gateway streams alive during long thinking pauses. This change uses Server-Sent Event (SSE) keepalive pings to prevent idle-timeout disconnects on upstreams of Google Vertex AI and Amazon Bedrock. To verify that the fix works, platform and developer-experience teams routing Claude Code through Vertex AI or Bedrock, should follow these steps:

1. Confirm you have the correct version (2.1.229 or later) and routing. Run claude --version to verify. Check the configuration for the proper CLAUDE_CODE_USE_*(VERTEX|BEDROCK) base URL, region, and other settings. Use a non-destructive task to pin a known-failing canary. Record the previous failure threshold from logs. Correlate one session across all hops by capturing X-Claude-Code-Session-Id in gateway access logs and provider request ID.

Record timestamps of request accepted, content/thinking activity, quiet interval, keepalive activity at each hop, content resumption, and terminal success. Separate the idle timeout (API_TIMEOUT_MS) from the keepalive ping interval. Do not change both at once. Classify the result based on whether the content resumes and completes with one request ID after the quiet interval.