400 streaming error with Claude Sonnet 5.5 and Opus 5.5 models — temperature is deprecated

[Teja-ssnc]

🏷️ Discussion Type

Bug

💬 Feature/Topic Area

Issues

Body

App version: [Github copilot v1.1.28]
Models affected: Claude Sonnet 5.5, Claude Opus 5.5+
Older claude models: Working fine

Error:
400 streaming error: streaming inference failed: bedrock returned 400
(ValidationException): The model returned the following errors:
temperature is deprecated for this model.

Steps to reproduce:

1. Select Claude Sonnet 5.5 or Opus 4+ in GitHub Copilot desktop
2. Send any message
3. Error appears immediately

Expected: Response streams normally
Actual: 400 error — newer Claude models on Bedrock no longer accept the temperature parameter

Guidelines

• I have read the above statement and can confirm my post is relevant to the GitHub feature areas Issues and/or Projects.

[github-actions[bot]]

💬 Your Product Feedback Has Been Submitted 🎉

Thank you for taking the time to share your insights with us! Your feedback is invaluable as we build a better GitHub experience for all our users.

Here's what you can expect moving forward ⏩

• Your input will be carefully reviewed and cataloged by members of our product teams. 
  • Due to the high volume of submissions, we may not always be able to provide individual responses.
  • Rest assured, your feedback will help chart our course for product improvements.
• Other users may engage with your post, sharing their own perspectives or experiences. 
• GitHub staff may reach out for further clarification or insight. 
  • We may 'Answer' your discussion if there is a current solution, workaround, or roadmap/changelog post related to the feedback.

Where to look to see what's shipping 👀

• Read the Changelog for real-time updates on the latest GitHub features, enhancements, and calls for feedback.
• Explore our Product Roadmap, which details upcoming major releases and initiatives.

What you can do in the meantime 💻

• Upvote and comment on other user feedback Discussions that resonate with you.
• Add more information at any point! Useful details include: use cases, relevant labels, desired outcomes, and any accompanying screenshots.

As a member of the GitHub community, your participation is essential. While we can't promise that every suggestion will be implemented, we want to emphasize that your feedback is instrumental in guiding our decisions and priorities.

Thank you once again for your contribution to making GitHub even better! We're grateful for your ongoing support and collaboration in shaping the future of our platform. ⭐

[MalikAhed]

The error is consistent with a provider-side request mismatch, not a problem in your prompt or repository. Bedrock is rejecting the request before generation because Copilot is sending temperature to a Claude model that no longer accepts it. AWS documents the same rule for newer Claude models: omit temperature, top_p, and top_k entirely rather than sending a default value.

There is no README or local GitHub setting that can remove a parameter from Copilot’s managed Bedrock request. Until GitHub ships the connector fix, use an older Claude model that still accepts the parameter or another available Copilot model. In the report, include the exact model ID/region, Copilot version, timestamp, and the full 400 response; the actionable fix for GitHub is to omit temperature for those model IDs and add a regression test for streaming.

AWS reference: https://docs.aws.amazon.com/bedrock/latest/userguide/model-card-anthropic-claude-opus-4-7.html. If switching models works around it, please click Mark as answer.