Politeness vs Enforcement: Why "Set HTTPS_PROXY" Isn't a Security Control

Short summary

Distinguish policy from enforcement: HTTPS_PROXY is asking nicely—agents can bypass via subprocess or prompt injection. Kernel-enforced controls (Linux UID separation, Kubernetes NetworkPolicy, nftables) actually prevent unauthorized egress. Evaluate vendors by whether they provide kernel-level guarantees or rely on voluntary compliance.

• •Policy controls (HTTPS_PROXY, system prompts, config allowlists) are voluntary—agents can bypass
• •Enforcement controls (kernel UID separation, NetworkPolicy, nftables) prevent agent circumvention
• •Real case: OAuth subprocess bypassed proxy by not inheriting environment variable

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