Claude Code produced Portuguese output in Bash tool response

Bug Description

Claude Code produced Portuguese-language output inside a Bash tool response, instead of responding in the user's configured language (Hebrew/English).

Output observed

EVOLUTION integration = funciona (Instance-Bot conectado ao número real). WHATSAPP-BAILEYS = não gera QR neste servidor.

Expected behavior

Claude Code should respond in the user's language (Hebrew for explanations, English for git/code). Portuguese was never used in this session and was not the user's language.

Environment

• Platform: Windows 11 Pro
• Shell: PowerShell + Bash tool
• Model: claude-sonnet-4-6
• Context: The output appeared as part of a Bash tool response during a WhatsApp/Evolution API integration task

Possible cause

The model may have "leaked" into Portuguese due to accumulated context, possibly triggered by Portuguese-adjacent technical terms (Evolution API, which has Portuguese documentation).