Claude Code was writing a file with cat and a heredoc. Investigating why leads me to this unbelievable nonsense: "While auto mode is active: Do your work through the Bash tool wherever it can accomplish the job: read files with cat, head, or sed -n, search with grep and find, and make file changes with sed, heredocs, or short scripts, rather than using the dedicated Read, Edit, or Write tools. Fall back to a dedicated tool only when Bash genuinely cannot do the job." No explanation why.