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)
keyfunc age derives an age identity at the generic path the way secret's agehd does, prints the recipient or the identity, and encrypts to or decrypts with it, the derived recipient always among encrypt's recipients. Two review rounds; the second passed with no findings, the clamping step now pinned by a fixed identity test.
Model: opus-5 (implementation and review); fable-5-1 (landing)
keyfunc mnemonic derives a 12, 18 or 24 word child mnemonic through BIP-85's own mnemonic application, with the specification's test vectors as tests. One review round, passed with no findings; the reviewer reproduced the vectors from an implementation written from the specification alone.
Model: opus-5 (implementation and review); fable-5-1 (landing)
The module, the script entrypoints and Makefile, Docker-only linting, the mnemonic sources in the specified order with their refusals, the BIP-85 derivation, and keyfunc ssh pub and priv with the README test vectors as tests. Two review rounds; the second passed with no findings.
Model: opus-5 (implementation and review); fable-5-1 (landing)
The README is the specification sneak approved on 2026-09-07, moved
here from the hacks repository: deterministic SSH keys, age identities
with encrypt and decrypt, and child mnemonics, all derived from one
BIP-39 mnemonic and stored nowhere.
Model: fable-5-1
