Claude Code Prompt Changes

In v2.1.124, the Claude Code system prompt grew by 166 tokens with 3 items added.

• A File modification detected (budget exceeded) reminder was added, which guides the model to read the file directly if the current content is needed, for cases where a file modification is detected but the diff is omitted due to other changes.
• Harness instructions was changed to remove the core-identity function call, and now specifies an intro sentence and a security note insertion point before the common harness instructions.
• REPL tool usage and scripting conventions was clarified to state that thenable shorthand is auto-awaited only at return time, and specifies that it should be awaited first when used for string concatenation, templates, or as arguments to other calls.

In the following v2.1.126, 87 tokens were removed, deleting the malware analysis reminder that followed Read tool calls. The guidance to check for malware every time a file is read, and the wording not to improve or expand on the analysis, were removed.