#Credentials that are a file

Some tools do not read a secret from the environment at all. They read a path: GOOGLE_APPLICATION_CREDENTIALS, KUBECONFIG, a .p12 keystore, a client certificate. hush export is the wrong answer to that — it writes every value in the vault to disk and leaves it there.

--materialize writes the one file that was asked for, hands the child the path, and removes it afterwards:

hush run --materialize GOOGLE_APPLICATION_CREDENTIALS -- node app.js
hush run --materialize KUBECONFIG=/tmp/kube.config -- kubectl get pods

With no = hush chooses a private path (a 0700 directory, removed with the file). With a path, that path is used exactly. Either way the file is 0600, created with wx so an existing file or a planted symlink is a refusal rather than a write through it, and removed even when the command fails. The value stays masked in the child's output: reading the file back does not print it.

Because this writes plaintext somewhere the caller chose, it is gated on reveal, not on run — it is the same class of act as hush get. There is no MCP tool for it, and there never will be: an agent that can materialise a value to a path and read that path has read the value.