fix(provider): add support for jp. prefix in Amazon Bedrock cross-region inference profiles

[ikeda-tomoya-swx]

Problem

When using Amazon Bedrock with the jp. cross-region inference profile prefix (e.g., jp.anthropic.claude-sonnet-4-5-20250929-v1:0), OpenCode incorrectly adds an additional region prefix, causing the model invocation to fail.

Currently, OpenCode only skips region prefixing for models starting with global., but AWS Bedrock also provides a jp. (Japan) cross-region inference profile, which is required for using certain models in the ap-northeast-1 (Tokyo) region.

Example

When configuring:

{
  "model": "amazon-bedrock/jp.anthropic.claude-sonnet-4-5-20250929-v1:0"
}

With AWS_REGION=ap-northeast-1, OpenCode currently transforms this to apac.jp.anthropic.claude-sonnet-4-5-20250929-v1:0, which is invalid.

Solution

Add jp. to the list of prefixes that skip automatic region prefixing, alongside the existing global. prefix.

Changes

• Modified packages/opencode/src/provider/provider.ts to recognize jp. prefix as a cross-region inference profile prefix that should not have additional region prefixes added.

Background

The jp. prefix is a Japan-specific cross-region inference profile provided by AWS Bedrock. Unlike the apac. prefix (which covers broader Asia Pacific regions), the jp. prefix routes requests specifically to the Japan (Tokyo) region infrastructure.

Some models like Claude Sonnet 4.5 are available with the jp. inference profile but not with the apac. profile, making this fix necessary for users in the Japan region.

Testing

Tested with:

• Model: jp.anthropic.claude-sonnet-4-5-20250929-v1:0
• Region: ap-northeast-1
• Result: Model invocation succeeds without incorrect prefix transformation