Bedrock: ANTHROPIC_MODEL ignored, cross-region inference profile used instead causing 403 errors

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 using AWS Bedrock with ANTHROPIC_MODEL set to a foundation model ID (e.g., anthropic.claude-opus-4-5-20251101-v1:0), Claude Code ignores this setting and internally converts it to a cross-region inference profile (us.anthropic.*).

This causes 403 errors when AWS Service Control Policies (SCPs) restrict access to specific regions (e.g., only us-west-2), because the inference profile load-balances requests across multiple regions including us-east-1 and us-east-2.

Key observations:

1. The UI shows arn:aws:bedrock:us-west-2::in… (inference profile) even when foundation model is specified
2. Error messages show requests being routed to us-east-2 despite AWS_REGION=us-west-2
3. Setting ANTHROPIC_BEDROCK_BASE_URL='https://bedrock-runtime.us-west-2.amazonaws.com' does not fix the issue
4. Using full ARN format also doesn't work: arn:aws:bedrock:us-west-2::inference-profile/us.anthropic.claude-opus-4-5-20251101-v1:0

What Should Happen?

When ANTHROPIC_MODEL is set to a foundation model ID (without us. or global. prefix), Claude Code should:

1. Use the foundation model directly, NOT convert it to an inference profile
2. Make API calls only to the region specified in AWS_REGION
3. Respect the user's explicit model configuration

This would allow users with region-restricted SCPs to use Claude Code with Bedrock by specifying the foundation model and staying within their allowed region.

Error Messages/Logs

403 {"Message":"User: arn:aws:iam::REDACTED:user/some-test-user is not authorized to perform: bedrock:InvokeModelWithResponseStream on resource: arn:aws:bedrock:us-east-2::foundation-model/anthropic.claude-opus-4-5-20251101-v1:0 with an explicit deny in a service control policy: arn:aws:organizations::REDACTED:policy/o-REDACTED/service_control_policy/p-REDACTED"}

Steps to Reproduce

1. Set up AWS credentials with an SCP that only allows access to us-west-2 region for Bedrock

1. Run Claude Code with the following environment variables:

AWS_REGION=us-west-2 \
AWS_ACCESS_KEY_ID="<your-key>" \
AWS_SECRET_ACCESS_KEY="<your-secret>" \
CLAUDE_CODE_USE_BEDROCK=1 \
ANTHROPIC_MODEL='anthropic.claude-opus-4-5-20251101-v1:0' \
claude

1. Observe that the UI shows arn:aws:bedrock:us-west-2::in… (inference profile) instead of the foundation model

1. Send any message (e.g., "test")

1. Observe the 403 error showing the request was routed to us-east-2

Additional attempts that also fail:

• Using us.anthropic.claude-opus-4-5-20251101-v1:0 (US inference profile)
• Using full ARN: arn:aws:bedrock:us-west-2::inference-profile/us.anthropic.claude-opus-4-5-20251101-v1:0
• Adding ANTHROPIC_BEDROCK_BASE_URL='https://bedrock-runtime.us-west-2.amazonaws.com'

All attempts result in the same error - requests are routed to us-east-2 instead of staying in us-west-2.

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.19

Platform

AWS Bedrock

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

AWS Bedrock Inference Profile Details

The aws bedrock list-inference-profiles output shows that the US inference profile routes to multiple regions:

"inferenceProfileName": "US Anthropic Claude Opus 4.5",
"description": "Routes requests to Claude Opus 4.5 in us-east-1, us-east-2, us-west-2.",

This is the expected behavior for inference profiles - they load balance across regions. However, when a user explicitly specifies a foundation model ID (without us. or global. prefix), Claude Code should NOT convert it to an inference profile.

Related CHANGELOG entries

• Line 236: "Fixed AWS Bedrock subagents not inheriting EU/APAC cross-region inference model configuration, causing 403 errors when IAM permissions are scoped to specific regions"
• Line 751: "Update Bedrock default Sonnet model to global.anthropic.claude-sonnet-4-5-20250929-v1:0"

This suggests the default behavior is to use inference profiles, but there should be a way to opt-out for users with region-restricted SCPs.

Suggested Fix

Add support for a configuration option or environment variable (e.g., ANTHROPIC_BEDROCK_DISABLE_INFERENCE_PROFILES=1) that forces Claude Code to use foundation models directly instead of converting to inference profiles.