[BUG] VS code Claude Code extension fails - Bedrock API Compatibility Issue - `eager_input_streaming` Parameter

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?

Environment

• Extension Version: 2.1.72 (win32-x64)
• VS Code Version: [Your VS Code version]
• OS: Windows 11
• API Provider: AWS Bedrock
• Model: us.anthropic.claude-sonnet-4-5-20250929-v1:0
• Region: us-east-1

Configuration

{
    "claudeCode.selectedModel": "us.anthropic.claude-sonnet-4-5-20250929-v1:0",
    "claudeCode.environmentVariables": [
        {"name": "AWS_PROFILE", "value": "ctsandbox"},
        {"name": "AWS_REGION", "value": "us-east-1"},
        {"name": "CLAUDE_CODE_USE_BEDROCK", "value": "1"}
    ]
}

Problem Description

When using Claude Code extension with AWS Bedrock as the API provider, all requests fail with a 400 error indicating that the eager_input_streaming parameter is not permitted by the Bedrock API.

Error Message

API Error: 400 tools.0.custom.eager_input_streaming: Extra inputs are not permitted

Steps to Reproduce

1. Configure Claude Code extension to use AWS Bedrock API (set CLAUDE_CODE_USE_BEDROCK=1)
2. Set up AWS credentials with a valid profile
3. Attempt to start any conversation or send any prompt through the VS Code extension
4. Request fails immediately with the error above

Expected Behavior

The extension should successfully communicate with AWS Bedrock API, similar to how the CLI version (claude command in terminal) works.

Actual Behavior

All API requests fail with 400 error because the extension is sending tools.0.custom.eager_input_streaming parameter which is not supported by AWS Bedrock's implementation of Claude API.

Root Cause Analysis

The eager_input_streaming parameter appears to be specific to Anthropic's native API and is not implemented in AWS Bedrock's API interface. The extension's binary (claude.exe) is hardcoding this parameter in tool configurations, causing incompatibility with Bedrock.

Workaround

The CLI version of Claude Code works correctly with Bedrock:

export AWS_PROFILE=ctsandbox
export AWS_REGION=us-east-1
export CLAUDE_CODE_USE_BEDROCK=1
claude -p "your prompt here"

This confirms the issue is isolated to the VS Code extension implementation.

Request

Please add conditional logic to exclude eager_input_streaming parameter when using AWS Bedrock as the API provider, or make this parameter optional/configurable.

Additional Context

• The CLI version (claude command) works perfectly with Bedrock, confirming the credentials and setup are correct
• The issue affects all operations through the VS Code extension when using Bedrock
• Located the issue in: resources/native-binary/claude.exe (binary file)

Suggested Fix

When CLAUDE_CODE_USE_BEDROCK environment variable is set, the extension should:

1. Detect Bedrock as the API provider
2. Strip out Bedrock-incompatible parameters like eager_input_streaming
3. Or provide a configuration option to disable this parameter

Thank you for looking into this issue!

<img width="1388" height="934" alt="Image" src="https://github.com/user-attachments/assets/435f33a2-9f5b-4bfc-88f9-eb8d6eec08e6" />

What Should Happen?

The extension should successfully communicate with AWS Bedrock API, similar to how the CLI version (claude command in terminal) works.

Error Messages/Logs

API Error: 400 tools.0.custom.eager_input_streaming: Extra inputs are not permitted

Steps to Reproduce

Configure Claude Code extension to use AWS Bedrock API (set CLAUDE_CODE_USE_BEDROCK=1)
Set up AWS credentials with a valid profile
Attempt to start any conversation or send any prompt through the VS Code extension
Request fails immediately with the error above

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.72 (win32-x64)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_