[BUG] Bedrock add-in sends us.anthropic.* inference profile from ap-southeast-2, causing 400

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?

When the Claude for Office add-in is configured with aws_region=ap-southeast-2, it invokes Bedrock using a US cross-region inference profile (us.anthropic.claude-opus-4-7). AWS Bedrock rejects this with 400 The provided model identifier is invalid because us.* profiles cannot
be invoked from APAC endpoints.

The add-in should use ap.anthropic.claude-opus-4-7 when the configured region is in the APAC partition.

Steps to reproduce:

1. Deploy manifest with aws_region=ap-southeast-2, entra_sso=1
2. Open the add-in in Excel for web (Chrome on macOS)
3. Hit Connect

Expected: Request goes to bedrock-runtime.ap-southeast-2.amazonaws.com/model/ap.anthropic.claude-opus-4-7/invoke

Actual: Request goes to bedrock-runtime.ap-southeast-2.amazonaws.com/model/us.anthropic.claude-opus-4-7/invoke → 400 The provided model identifier is invalid

Environment:

• Build: b2934996a310d14d9341cbeb6b21eca12f40aba7
• Host: Excel$Web (Chrome on macOS)
• Manifest version: unified-1.0.0.12
• aws_region: ap-southeast-2

What Should Happen?

Claude for Excel should function correctly using a custom manifest to access AWS Bedrock in ap-southeast-2.

Expected: Request goes to bedrock-runtime.ap-southeast-2.amazonaws.com/model/ap.anthropic.claude-opus-4-7/invoke

Error Messages/Logs

Claude for Office connection failed (Bedrock)
Build: b2934996a310d14d9341cbeb6b21eca12f40aba7

400 The provided model identifier is invalid.

Request:
  aws_role_arn: arn:aws:iam::217425570363:role/ClaudeBedrockAccess
  aws_region: ap-southeast-2

Manifest params:
  m: unified-1.0.0.12
  aws_role_arn: arn:aws:iam::217425570363:role/ClaudeBedrockAccess
  aws_region: ap-southeast-2
  entra_sso: 1
  auto_connect: 0
  et: 

Bootstrap response:
  (not called)

Raw error:
400 The provided model identifier is invalid.

Steps to Reproduce

Steps to reproduce:

1. Deploy manifest with aws_region=ap-southeast-2, entra_sso=1
2. Open the add-in in Excel for web (Chrome on macOS)
3. Hit Connect

Claude Model

Other

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Excel$Web Build: b2934996a310d14d9341cbeb6b21eca12f40aba7

Platform

Other

Operating System

macOS

Terminal/Shell

Other

Additional Information

_No response_