[BUG] Sonnet 4.5 cannot both be specified for this model error message

[ronyblum]

Problem (one or two sentences)

When trying to invoke Sonnet 4.5 under Bedrock API, get error message "Sonnet 4.5 cannot both be specified for this model error message". Not sure if it happens as will when invoking Anthropic API

Context (who is affected and when)

Happens when invoking the freshly released model Sonnet 4.5 under Bedrock API

Reproduction steps

1. Select Bedrock as API Provider
2. For Model, select anthropic.claude-sonnet-4-5-20250929-v1:0
3. Run a simple task
4. View the error message received

Expected result

The task starts and provide response

Actual result

Error Messaeg "the model returned the following errors: temperature and top_p cannot both be specified for this model. Please use only one

Variations tried (optional)

No response

App Version

3.28.11

API Provider (optional)

AWS Bedrock

Model Used (optional)

Claude Sonnet 4.5

Roo Code Task Links (optional)

No response

Relevant logs or errors (optional)

[roomote]

I'm exploring a potential fix for this issue. The error indicates that AWS Bedrock's implementation of Claude Sonnet 3.5 v2 doesn't accept both temperature and top_p parameters simultaneously. I'll investigate the codebase to ensure we only send one of these parameters when using this model with Bedrock.

[roomote]

I've opened PR #8378 with a fix for this issue: #8378

The fix removes the topP parameter from Bedrock API calls, as AWS Bedrock doesn't allow both temperature and topP to be specified simultaneously for certain models including Claude Sonnet 3.5 v2.

The PR includes comprehensive test coverage to ensure the fix works correctly. Some CI checks are currently failing, but these appear to be pre-existing issues unrelated to this change (the integration tests pass, and the failures are in platform unit tests that don't involve the Bedrock provider changes).

Please review the PR when you have a chance. Feedback welcome!

[dltompki]

@ronyblum using the custom ARN option for accessing sonnet 4.5 is working fine for me

[ronyblum]

@ronyblum using the custom ARN option for accessing sonnet 4.5 is working fine for me

@dltompki Using custom arn doesn't provide all the options such as prompt caching