[BUG] No feedback in VSCode extension when bedrock auth token is expired

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

I am using Claude code via the extension with Amazon bedrock.

My aws creds expire every day. When this has happened and I interact with Claude via the extension it just hangs saying "Manifesting..." etc and I am never told that my tokens have expired:

<img width="179" height="103" alt="Image" src="https://github.com/user-attachments/assets/395b25c8-1c39-45a8-9390-4380066d6bba" />

If I open up "Output > Claude VS Code" then I can see the error:

From claude: [ERROR] Error streaming, falling back to non-streaming mode: 403 The security token included in the request is invalid

When using Claude Code from the CLI I do see a message:

<img width="458" height="67" alt="Image" src="https://github.com/user-attachments/assets/c82642a7-5abf-4bca-a6ef-8c83e7c8531e" />

What Should Happen?

The VSCode extension should show the security token error when it doesn't have the relevant permissions to connect to bedrock rather than just spinning forever

Error Messages/Logs

Steps to Reproduce

Try to prompt Claude in the extension when configured for bedrock without a valid token in your ~/.aws/credentials

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.0.13 (Claude Code)

Platform

AWS Bedrock

Operating System

macOS

Terminal/Shell

VS Code integrated terminal

Additional Information

_No response_