• Structured logging to ~/.purple/purple.log
• --verbose flag enables debug-level logging. PURPLE_LOG env var for finer control (trace/debug/info/warn/error/off)
• purple logs subcommand: --tail to follow in real time, --clear to delete
• Log entries carry fault domain prefixes: [external] for remote/tool errors, [config] for local config issues, [purple] for internal errors
• Startup banner records purple version, SSH version, terminal, providers and askpass sources for diagnostics
• Automatic log rotation at 5 MB