Under the hood
The main system prompt gained new text, including a mention of 'control'
What
The main system prompt, the instructions Claude Code sends to the model at the start of every conversation, gained additional text. This was measured directly from the prompt as sent by the running client, across both the CLI and SDK versions and across anonymous and account-linked variants, and the added text includes the word control.
Why
Changes to the system prompt can affect how Claude behaves in subtle ways across all sessions, since this prompt is sent every time regardless of what a user asks. The exact content and purpose of the addition are not established beyond the one quoted word.
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubt
The evidence only confirms new text was added and that it contains the word 'control'; what the addition says or does is not established.