[ENHANCEMENT] Add Prompt Caching Toggle to AWS Bedrock Settings

[wisestmumbler]

Problem (one or two sentences)

Users need the ability to toggle prompt caching when using AWS Bedrock.

The toggle should default to ON/checked and should be visible on the UI.

If feasible - Inference Profiles should also have an option in the settings.

Please reference:
#8669
#8670

https://aws.amazon.com/bedrock/cost-optimization/#:~:text=Use%20prompt%20caching%20to%20reduce,repeated%20prompt%20prefixes%20between%20requests.
https://aws.amazon.com/blogs/machine-learning/track-allocate-and-manage-your-generative-ai-cost-and-usage-with-amazon-bedrock/

Note:
This feature may already be partially implemented (#8670 (comment)) but users are unable to see the benefits

Context (who is affected and when)

Any user using AWS Bedrock would benefit from significant cost and latency reductions.
And have the confidence to know that prompt caching is on while having an escape hatch in case they need to turn it off

Desired behavior (conceptual, not technical)

In the providers settings when AWS Bedrock is chosen the option for prompt caching should be with the other checkboxes.

Of course, you should verify that prompt caching is working behind the scenes

Constraints / preferences (optional)

Ensure it works with most common AWS Bedrock setups, custom ARN, and govcloud.

Request checklist

• I've searched existing Issues and Discussions for duplicates
• This describes a specific problem with clear context and impact

Roo Code Task Links (optional)

No response

Acceptance criteria (optional)

No response

Proposed approach (optional)

No response

Trade-offs / risks (optional)

No response

[roomote]

I've analyzed this issue and here's my proposed implementation plan:

Current State

The AWS Bedrock prompt caching feature is already implemented in the codebase:

• Backend logic exists in src/api/providers/bedrock.ts (uses awsUsePromptCache option)
• UI toggle exists in webview-ui/src/components/settings/providers/Bedrock.tsx (lines 198-216)
• Most Claude models have supportsPromptCache: true configured with proper cache pricing

Issue

The toggle currently:

1. Defaults to OFF (false)
2. Is only visible when the selected model has supportsPromptCache: true

Proposed Changes

1. Change Default Value to ON

Modify the initialization logic so awsUsePromptCache defaults to true for AWS Bedrock provider when not explicitly set. This will be done by updating the default value handling in the provider settings initialization.

2. Ensure Toggle Visibility

The toggle already shows for models with supportsPromptCache: true (which includes all modern Claude models). No changes needed here as the current behavior is correct - the toggle should only appear for models that actually support prompt caching.

Files to Modify

1. src/core/config/SettingsUtils.ts or equivalent - Add default value for awsUsePromptCache when Bedrock provider is selected
2. webview-ui/src/components/settings/providers/Bedrock.tsx - Update the checkbox to use the new default

Regarding Inference Profiles

The codebase already has cross-region and global inference profile support. If you need additional inference profile options, please clarify what specific functionality is needed.

This approach ensures:

• Cost savings and latency improvements are enabled by default for users
• Users retain the option to disable it if needed
• The toggle is appropriately shown only for models that support caching

Please mention @roomote in a comment saying that you approve this plan, and I'll proceed with the implementation.

[wisestmumbler]

@roomote your plan is a good one but incomplete for me

I verified that choosing a newer claude model does make the checkbox appear.

Your plan to default them to true is good.

In my case it is likely the custom ARN that does not allow the checkbox - it should since my ARN is pointed at a new version of claude. Perhaps custom ARN should be treated as an advanced "the user knows what they are doing" type of option and all available options (including prompt caching) should be available.

I am not sure what exactly @dempsey-ryan and @mcclochette were seeing in the comments for #8670

[roomote]

Thanks for the feedback! I understand the issue now - when using a custom ARN, the prompt caching toggle is not visible even though the custom ARN may point to a newer Claude model that supports caching.

I will update my implementation plan to:

1. Show the prompt caching toggle for custom ARN users (treating it as an advanced option where users know what they are doing)
2. Default the setting to true

I will explore the codebase and open a PR to share progress. Feedback and guidance are welcome.

[roomote]

Opened a PR with my attempt at addressing this: #10577

Summary of changes:

1. Enabled the prompt caching toggle for custom ARN users (treating it as an advanced option where users know what they are doing)
2. Defaulted the prompt caching setting to ON for all Bedrock users

Feedback welcome!

[hannesrudolph]

this setting is already present.