[BUG] Incorrect Model Invocation: Requests Sent to Claude 3.5 Haiku Instead of Configured Claude Sonnet 4, Causing Slow Performance with Bash Tool Execution

Environment

• Platform (select one):
• [ ] Anthropic API
• [X] AWS Bedrock
• [ ] Google Vertex AI
• [ ] Other:
• Claude CLI version: 1.0.61 (Claude Code)
• Operating System: macOS 15.5

Bug Description

Despite configuring ANTHROPIC_MODEL='us.anthropic.claude-sonnet-4-20250514-v1:0', logs indicate requests are being sent to the Claude 3.5 Haiku model (us.anthropic.claude-3-5-haiku-20241022-v1:0). This issue is particularly noticeable when agents execute the Bash tool, resulting in slow performance.

This is especially evident when Agents are trying to run Bash tool and it takes a long time to execute this.

Steps to Reproduce

1. Configure AWS Bedrock credentials with the Sonnet model (us.anthropic.claude-sonnet-4-20250514-v1:0).
2. Run the Claude CLI with ANTHROPIC_LOGS=debug.
3. Observe the logs when agents execute the Bash tool.

Expected Behavior

The Bash tool should execute promptly using the configured Sonnet model.

Actual Behavior

The Bash tool executes slowly, and logs show requests being sent to the Haiku model instead of the Sonnet model.

Additional Context

One example of the request

[log_d9cf71] sending request {
method: 'post',
url: 'https://bedrock-runtime.us-east-1.amazonaws.com/model/us.anthropic.claude-3-5-haiku-20241022-v1:0/invoke-with-response-stream',