The first sftp connection now lists ~/.ssh before it fetches
authorized_keys. The file reads as empty in just two cases: sftp reports
~/.ssh itself as not there, or the listing succeeds and the fetch then
reports the file as not there. A directory that is there but cannot be
entered, or a file that cannot be read, fails the run and writes nothing,
so a ~/.ssh whose mode shuts the user out is no longer read as a host
with no file and replaced by one holding the new key alone. The write
connection makes ~/.ssh and sets 0700 only when the read found none; an
existing directory keeps its mode.
Model: opus-4-8
Every direct dependency moves to its current release, golang.org/x/crypto first: keyfunc ssh to serves keys through its ssh/agent package, which has had security fixes since the pinned 2025-05 version. go.mod and go.sum only; no code changed and the SSH, age and child mnemonic test vectors pass unedited, so no derived key moves.
Model: opus-4-8 (implementation); fable-5-1 (summary)
main.go moves unchanged to cmd/keyfunc/main.go, where REPO_POLICIES.md puts Go entrypoints, and the Makefile build target builds ./cmd/keyfunc. The binary is still written to ./keyfunc and still carries the stamped version.
Model: opus-4-8 (implementation); fable-5-1 (summary)
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
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