Reddit user reports Opus 5 losing language precision

What the research found

Single Reddit user anecdote reporting recent Opus 5 degradation in language precision, arithmetic and a softer, more clarifying-question style; no official change notice, version, or date of rollout cited.

Claims and how well the evidence supports them

1. Opus 5 language quality dropped in the last few days with broken sentences and arithmetic errors 95%
2. Opus 5 personality became softer and more agreeable with identical custom instructions 97%
3. The author has used Opus 5 daily for months with the same project setup 98%
4. Reasoning quality still seems fine according to the author 98%

Evidence

• reddit.com https://reddit.com/r/ClaudeAI/comments/1xbegio/opus_5_sudden_drop_in_language_precision_and_tone

Actionability rated low.