PS Product SecurityKnowledge Base

๐Ÿƒ Vendor Agents, Runners, and Build-Integration Trust Boundaries

Intro: Agents and runners are attractive because they automate a lot. They are dangerous for the same reason. Once deployed, they often gain filesystem, network, secret, or code visibility far beyond what the team consciously reviewed.

What this page includes

  • trust-boundary review for agents and runners
  • questions for vendor-hosted and self-hosted execution
  • containment ideas when an agent or runner is suspected
  • how to separate convenience from authority

Review questions

  • what code will this component execute, and who controls that code?
  • what network destinations can it reach?
  • what secrets or service accounts are present at runtime?
  • can it mutate artifacts, manifests, or production configuration?
  • what telemetry exists if it behaves badly?

Safer patterns

  • dedicate higher-trust runners for production paths;
  • minimize mounted secrets and workspace reuse;
  • quarantine suspicious runners quickly;
  • keep vendor agents away from the most sensitive tenants or environments until proven necessary.

Author attribution: Ivan Piskunov, 2026 - Educational and defensive-engineering use.