What did @AnthropicAI do with his latest Claude Desktop update? I feel like there was a major system prompt/harness upgrade here. Opus 5.5 f…

On October 14, 2026 Chad Moran posted a question on Twitter about AnthropicAI’s latest Claude Desktop update, noting what appeared to be a major system‑prompt or harness upgrade that made Opus 5.5 look like Opus 5.8. The tweet, which referenced @trq212, was widely viewed (about 173 k views) and drew significant interaction—over 1.4k likes, 46 retweets, and 11 replies.

Source: Boris Cherny (X) | 2026-10-14