[Bug] Claude Sonnet requests downgraded to Opus without clear policy explanation

Question

**Bug Description**
Each of the two prompts on Fable 5 I have run on this project have been flagged and downgraded to Opus. I am not doing frontier research here, I just want a c++ library for training an LLM on my local GPU.

**Environment Info**
- Platform: linux
- Terminal: xterm-256color
- Version: 2.1.197
- Feedback ID: 92e8f95a-63fa-420f-b66b-7e90974be466

**Errors**
```json
[]
```