No Proxy, No Fetch Tool: Capability-Scoped Internet Access for In-Cluster Agents
Introduction Consider an agent running in a cluster or on a server that needs to read the news. The customary response is to provide an HTTP client and permit it to fetch URLs, perhaps through an egress proxy intended to impose a measure of network hygiene. The agent in question is an in-cluster assistant with material access to its environment. It can receive a projected ServiceAccount token, whose effective authority derives from Kubernetes RBAC; it can control home automation; and it can reach several important internal services. Giving a system with that degree of reach a general-purpose fetch(url) tool creates a direct security problem: every page it reads becomes a potential source of adversarial instruction, and every host on the internet becomes a potential destination for whatever information the agent can assemble. ...
