How to Add a Local Policy Gateway Between Your Coding Agent and Its LLM

Developers using AI coding agents face a security gap: responses from model providers reach the editor with no intermediate inspection, potentially exposing risks like echoed API keys or unsafe code patterns. A proposed solution involves running a local proxy that sits between the agent and the provider, inspecting response streams and deciding whether to allow, redact, or block content before it reaches the developer. The walkthrough uses an open-source Go-based tool called Cencurity Engine, which forwards the agent's existing authorization headers without storing credentials itself. Compatible agents and IDEs — including Roo Code, Continue, Claude Code, and Gemini CLI — support overriding the API base URL, making the setup straightforward. The author emphasizes verifying the gateway is actively intercepting traffic rather than assuming protection, since a misconfigured setup can silently pass all requests.