Let your on-call agent look at every host. Let it change none of them.

What ships ready to use

The read-only Linux pack covers network, disk, memory, services and logs. Every tool in it is effect: read. It is tested on Debian, Ubuntu and Alpine, including an Alpine image with BusyBox and no extra packages. A flavor the spec does not accept is refused before it runs.

Read-only twice

1. In the spec. Every action in the pack reads. There is no write action to grant by mistake.
2. On the host. The connector profile linux-readonly allows each of those programs at max_effect: read. The machine owner sets that limit, and the bastn connector enforces it locally, whatever the policy on the gateway says.

What the agent sees

Illustrative calls from an on-call agent during an alert:

oncall-agent -> systemctl_status  unit nginx · on web-42       allowed   audited
oncall-agent -> journalctl_unit   unit nginx · on web-42       allowed   audited
oncall-agent -> route_get         address 10.0.4.12 · on web-42   allowed   audited

Each call has typed arguments. A value that does not match its pattern never reaches the host.

Every host, by label

Enrol each host with labels such as web, db or prod. Give the on-call agent the read actions on those labels. A new host gets them as soon as its connector enrols.

When it needs to change something

Reading is where most triage ends. When a fix is needed, hand it to an agent whose menu includes the fix, with the risky calls held for you. See remediation with approvals.