[BUG] Bedrock Custom ARNs to have "Enable Reasoning" checkbox

[ronyblum]

Problem (one or two sentences)

In Bedrock API Provider, some models have a checkbox "Enable reasoning". For custom ARN, the checkbox doesn't exist, sending reasoning flag by default, which is not supported by part of the models and returning error

Context (who is affected and when)

In Bedrock API Provider, some models have a checkbox "Enable reasoning". For custom ARN, the checkbox doesn't exist, sending reasoning flag by default, which is not supported by part of the models and returning error. For example nova lite custom arn return "Error: Unknown Error: The model returned the following errors: Malformed input request: #: extraneous key [thinking] is not permitted, please reformat your input and try again." without any option to disable the flag

Reproduction steps

1. Select Bedrock API Provider
2. For model, select Nova custom arn, for example arn:aws:bedrock:us-east-1:<ACCOUNT_ID>:inference-profile/us.amazon.nova-2-lite-v1:0

Expected result

Checkbox to disable reasoning, not sending the thinking flag to the models

Actual result

Error: Unknown Error: The model returned the following errors: Malformed input request: #: extraneous key [thinking] is not permitted, please reformat your input and try again.

Variations tried (optional)

No response

App Version

3.36.2

API Provider (optional)

Amazon Bedrock

Model Used (optional)

No response

Roo Code Task Links (optional)

No response

Relevant logs or errors (optional)

[roomote]

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

Problem Analysis

When using custom ARNs with Bedrock, the "Enable reasoning" checkbox doesn't appear in the settings UI. The system attempts to guess model capabilities from the ARN string, but:

1. For models like Nova Lite, it can't accurately determine if reasoning is supported
2. When reasoning is enabled by default (via settings), these models return errors like: Malformed input request: extraneous key [thinking] is not permitted

Proposed Solution

Add an explicit "Enable Reasoning" checkbox in the Bedrock provider settings that appears when using custom ARNs. This will give users control over the reasoning feature regardless of the guessed model capabilities.

Implementation Steps:

1. Update Bedrock Settings UI (webview-ui/src/components/settings/providers/Bedrock.tsx)

   • Add a checkbox similar to the existing VPC endpoint checkbox
   • Show it when selectedModelId === "custom-arn" && apiConfiguration.awsCustomArn
   • Bind to a new setting field (e.g., awsCustomArnEnableReasoning)

2. Update Backend Logic (src/api/providers/bedrock.ts)

   • When using custom ARNs, check the new awsCustomArnEnableReasoning setting
   • Only enable thinking if explicitly set by the user for custom ARNs
   • Maintain existing behavior for dropdown-selected models

3. Update Types (packages/types)

   • Add awsCustomArnEnableReasoning?: boolean to ProviderSettings

Benefits:

• Users have explicit control over reasoning for custom ARNs
• Prevents errors on models that don't support reasoning
• Maintains backward compatibility with existing configurations
• Follows the established pattern of Bedrock-specific settings

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

[ronyblum]

@roomote plan approved

[roomote]

I've seen your approval and will implement the changes to add an "Enable Reasoning" checkbox for Bedrock custom ARNs. I'll open a PR to share progress.

[roomote]

Opened a PR with my attempt at addressing this: #10041

The implementation adds an "Enable Reasoning" checkbox that appears in Bedrock settings when a custom ARN is used. This gives users explicit control over whether reasoning is enabled for their custom ARN models, preventing errors on models like Nova Lite that don't support reasoning.

Feedback welcome!