[Model behavior] Binds the app's default port for tests and kills its listener without checking ownership

To run tests, the model started a local server on the application's default well-known port (the one the user's own environment normally uses) instead of a free scratch port, and afterwards killed whatever process was listening on that port without first checking whether it belonged to the user. In this instance the process turned out to be the model's own, but the model only verified that after the kill.

Steps to reproduce

1. Work in a repo whose service listens on a default port the user commonly has a long-running instance on.
2. Ask the model to verify a change against a running server.
3. Observe: the model binds the default port, then runs a "kill whatever holds this port" command at the end.

Expected

Use an unused port, and never kill a process on a shared port without confirming it was started by the model.

Model: Claude Opus 5.5 (claude-opus-5-5[1m]), Claude Code CLI, session on 2026-10-05.
Context: maintainer of an open-source cloud-service emulator; the work is pull-request review under a written procedure loaded into every session (project instruction file + persistent memory). No personal data, repository names, PR numbers or handles are included.