Every element of the derivation path is hardened, so an index above
2147483647 has no child to derive: the hardened offset wrapped around
and the tool silently produced a non-hardened key that no other
implementation reading the path as written would reproduce. Such an
index is now refused with a message before anything is derived, and
tests pin the refusal at both the derivation and the command level.
Also use the hook path variable in script/install-precommit instead of
repeating the literal beside it.
Model: opus-5
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