I've just published tethered, a Python package for runtime network egress control, which is dependency-free, zero-infrastructure, and very easy to set up. It takes one function call to restrict which hosts your code can connect to.

Use cases: - Supply chain defense. A compromised dependency can't phone home if egress is locked to your known services. - AI agent guardrails. Constrain LLM-powered agents to only the APIs they need. - Test isolation. Ensure your test suite never accidentally hits production endpoints. - Least-privilege networking. Declare your app's network surface the same way you declare its dependencies.

github.com/shcherbak-ai/tethered