Model dropdown hardcodes us. region prefix and ignores Bedrock region configuration

[Poojan-AI]

Description:

When using Claude Code with AWS Bedrock in non-US regions (e.g., `ap-south-1`), the model switcher dropdown has several issues that make it unusable:

Issues:

1. Hardcoded region prefix: When selecting a model from the dropdown (e.g., "Opus 4.5"), the extension writes `us.anthropic.claude-opus-4-5-20251101-v1:0` to `claudeCode.selectedModel`, regardless of the configured AWS region. This causes API errors when using non-US regions that require `global.` prefix.

2. Incorrect UI display: The dropdown shows "Default (currently Sonnet 4.5)" even when `global.anthropic.claude-opus-4-5-20251101-v1:0` is configured in settings.

3. Ignores environment variables: The `ANTHROPIC_MODEL` environment variable is set to Opus, but "Default (recommended)" still uses Sonnet.

Environment:

```json
{
"claudeCode.selectedModel": "global.anthropic.claude-opus-4-5-20251101-v1:0",
"claudeCode.environmentVariables": [
{
"name": "CLAUDE_CODE_USE_BEDROCK",
"value": "1"
},
{
"name": "AWS_REGION",
"value": "ap-south-1"
},
{
"name": "ANTHROPIC_MODEL",
"value": "arn:aws:bedrock:ap-south-1:588625695333:inference-profile/global.anthropic.claude-opus-4-5-20251101-v1:0"
}
]
}
```

Steps to Reproduce:

1. Configure Claude Code to use AWS Bedrock in `ap-south-1` region
2. Set `claudeCode.selectedModel` to `global.anthropic.claude-opus-4-5-20251101-v1:0`
3. Click on the model dropdown and select "Opus 4.5"
4. Settings are changed to `us.anthropic.claude-opus-4-5-20251101-v1:0`
5. API error occurs: "400 The provided model identifier is invalid"

Expected Behavior:

• Extension should detect the configured AWS region and use the appropriate inference profile prefix (`global.` for cross-region profiles, `us.` for US regions)
• Or, provide a setting to configure the region prefix
• Or, read from environment variables to determine the correct model identifier
• UI should accurately display which model is currently selected

Workaround:

Manually edit `settings.json` and avoid using the dropdown entirely. This is tedious and defeats the purpose of having a UI.

Impact:

This makes Claude Code unusable for Bedrock users in non-US regions who need to switch models frequently.

[github-actions]

Found 3 possible duplicate issues:

1. [FEATURE] Regional Model Selection in Claude Code #19624
2. [FEATURE] Environment Variables/mapping for specific model version overrides #18674
3. Explore subagents ignore ANTHROPIC_SMALL_FAST_MODEL and use hardcoded Haiku model with wrong region/format #19578

This issue will be automatically closed as a duplicate in 3 days.

• If your issue is a duplicate, please close it and 👍 the existing issue instead
• To prevent auto-closure, add a comment or 👎 this comment

🤖 Generated with Claude Code

[neefrehman]

Additional reproduction case: EU region (eu-west-2)

Experiencing the same issue with EU region configuration. When selecting "Opus" from the VSCode extension model switcher, it attempts to use us.anthropic.claude-opus-4-5-20251101-v1:0 instead of respecting the configured ANTHROPIC_DEFAULT_OPUS_MODEL environment variable.

Configuration in ~/.claude/settings.json:

{
  "env": {
    "CLAUDE_CODE_USE_BEDROCK": "1",
    "AWS_REGION": "eu-west-2",
    "ANTHROPIC_DEFAULT_OPUS_MODEL": "eu.anthropic.claude-opus-4-5-20251101-v1:0",
    "ANTHROPIC_DEFAULT_SONNET_MODEL": "eu.anthropic.claude-sonnet-4-5-20250929-v1:0",
    "ANTHROPIC_DEFAULT_HAIKU_MODEL": "eu.anthropic.claude-haiku-4-5-20251001-v1:0"
  },
  "model": "eu.anthropic.claude-opus-4-5-20251101-v1:0"
}

Error received:

API Error (us.anthropic.claude-opus-4-5-20251101-v1:0): 400 The provided model identifier is invalid.

Expected: Model switcher should use eu.anthropic.claude-opus-4-5-20251101-v1:0 as specified in ANTHROPIC_DEFAULT_OPUS_MODEL.

This confirms the issue affects both APAC regions (as originally reported) and EU regions. The VSCode extension's model switcher appears to completely ignore the region-specific environment variables.

[github-actions]

Closing for now — inactive for too long. Please open a new issue if this is still relevant.

[github-actions]

This issue has been automatically locked since it was closed and has not had any activity for 7 days. If you're experiencing a similar issue, please file a new issue and reference this one if it's relevant.