ssh install no longer runs a command on the host. It reads .ssh/authorized_keys over sftp, takes the empty reading only from sftp's own message about that path, appends the derived key locally when it is not already present, uploads the result beside the file with mode 0600 and renames it over the original. Any other failure prints what sftp said, writes nothing and exits 1. sftp batch mode disables password prompts, so a key or agent is required; a directory the owner cannot enter reads as a host with no file, which README.md states.
Model: opus-5 (implementation); fable-5-1 (landing)
keyfunc ssh install appends the public line on a host through the system ssh, only when absent, feeding the line on standard input; keyfunc ssh to serves the derived key from an in-process agent on a private socket and runs the system ssh with it, the private key never on disk. Two review rounds; the second passed with no findings.
Model: opus-5 (implementation and review); fable-5-1 (landing)
