Give a sandbox a token without revealing it

A secret lets code in a sandbox call an API without ever seeing the credential. The guest gets a placeholder in an environment variable, and kumobad swaps in the real value only in HTTPS requests to the hosts you allow.

Before you begin, have a started sandbox in $id with network mode open or allowlist.

1. Set the secret:

   kumoba set-secrets "$id" secrets='[{"name":"gh","value":"ghp_your_token","hosts":["api.github.com"],"envVars":["GITHUB_TOKEN"]}]'

   To keep the token out of your shell history, put the JSON in a file and pass secrets=@secrets.json.

2. Use it from the sandbox like a normal token:

   kumoba exec "$id" -- sh -c 'curl -sS -H "Authorization: Bearer $GITHUB_TOKEN" https://api.github.com/user'

   Inside the guest, $GITHUB_TOKEN holds a placeholder such as kmb_secret_…. The request to api.github.com leaves kumobad with the real token. A request to any other host carries only the placeholder.

set-secrets replaces the sandbox's whole set; secrets='[]' removes them. kumoba delete-secrets --names gh removes a secret from every sandbox.

How secrets work explains the guarantees and limits.