Bedrock streaming: no idle timeout on hung connections

Problem

When using Claude Code with Bedrock (CLAUDE_CODE_USE_BEDROCK=1), streaming responses occasionally hang indefinitely. The TCP connection establishes successfully, but no further bytes arrive. Claude Code waits forever with no visible output — the user sees a frozen session with no spinner, no thinking indicator, nothing.

Evidence

• CloudWatch shows zero throttles, zero client errors, zero server errors during the hang
• Normal invocation latency for this model (Opus 4.6, cross-region us. profile) is 4–14s average, 26s max
• The hung requests exceed 100+ seconds with no data
• Ctrl+C (user interrupt) recovers the session — confirming the client is alive, just waiting on a dead socket
• This occurs across both Opus 4.8 and Opus 4.6, so it's not model-specific
• Happens with cross-region inference enabled (us.anthropic.claude-opus-4-6-v1)

Expected behavior

Claude Code should detect "no bytes received in N seconds" on an active streaming connection and either:

1. Abort the request and retry (transparent to user), or
2. Surface a "connection stalled, retrying..." message

A 30–60s idle timeout on the streaming read would catch this without interfering with legitimate long first-token latency.

Environment

• Claude Code 2.1.159
• macOS (Darwin 25.1.0)
• CLAUDE_CODE_USE_BEDROCK=1
• AWS_REGION=us-east-1
• Model: us.anthropic.claude-opus-4-6-v1[1m]
• Cross-region inference active (us-east-1, us-east-2, us-west-2)

Reproduction

Not reliably reproducible on demand. Occurs intermittently (~1-3 times per heavy-use day with 3-4 concurrent sessions). More likely during extended sessions with large context windows.