watching from outside the boundary

A supervisor that can only learn what its workers choose to tell it is not supervising. The requirement was observation from the host, outside the isolation boundary, without the worker's cooperation and without the power to change what was being observed.

Two surfaces were built for that. The first was a ring buffer in shared memory that the worker writes unconditionally and the host can follow the way one follows a growing log, wrap-around included. The second was a read-only client for the worker's own control endpoint, found by matching a stored session record against the worker's directory instead of by hardcoding an address that would rot.

The hard part was not the reading. It was telling the difference between nothing happening and nothing visible. A missing endpoint and a silent endpoint are different facts, and collapsing them is how a dashboard starts reporting health it does not have.

So the states are explicit. No endpoint, and the row is exactly what it was before the observation existed. Endpoint present but not answering, and the row says the detail is unavailable while keeping the last confirmed state. Answers, and the extra columns fill in. One request per connection, no writes, no side effects, and the client runs against live sessions without disturbing them.

What this proves: observability was built as a separate surface that assumes nothing, and the system refuses to let a failed measurement wear the costume of a negative result.