Billing warning pop-up when changing model context size mid-session to prevent budget exhaustion

[evguenipetkov]

🏷️ Discussion Type

Product Feedback

💬 Feature/Topic Area

Copilot Workspace

Body

Currently, the UI allows users to change the model context window size (e.g., switching from 272k to 1M tokens) mid-session without any feedback or warning.
Because token caching relies on a stable prompt prefix, changing this context setting invalidates the prompt cache and forces an un-cached "cold start." For a developer with a large active session this single click causes a massive spike in tokens used. In my case I switched GPT 6.1 Sol from 272 k to 1M context size and the bill for the prompt result switched from 443 thousand to 4.4 million tokens !!!
Proposed Solution:
Introduce a confirmation modal dialog when a user attempts to change context limits or models mid-session while a chat history is active.
Example:
Message: "Warning: Switching your context size will invalidate your active prompt cache. Your entire active conversation history and workspace references will be re-processed at [Model Tier] rates, which may result in a significantly higher token cost for your next request.
To avoid this, consider clearing your active chat thread before switching tiers."
Buttons: [Proceed anyway] | [Clear chat and switch] | [Cancel]
Why this matters:
It is not ok to suddenly lose your monthly budget in one prompt.

[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. ⭐