monkeysSecret
A secret is what a key holds: the API key, token or password itself.
It is the only thing monkeys exists to keep, and the only thing it never
prints.
Where it goes
A secret enters the vault through remember, typed at a prompt, piped in or
pasted from the clipboard. It leaves one way only: into the environment of a
command that run starts. What that command prints comes back through
monkeys, which replaces the secret with [redacted KEY] on the way.
Replacing one
Remembering a secret under a key that already has one replaces it, and nothing says so. The previous secret is gone; the vault keeps no history to recover it from.
Reading one
No monkeys command prints a secret. To read one in full, open the vault
itself, Keychain Access on macOS or the desktop's secret browser on Linux,
where the decision to look at one is yours and deliberate.