From your .env to the model's servers. What your coding agent sends without telling you, the three moves, and what they do not fix. The agent reads the folder. To understand the project: source code, configuration, .env with the payment key. The key leaves in the request. Readable by the model's servers. Nobody shows you what leaves. See. mitmproxy, free and open source: let your agent work for ten minutes, then read the calls. Separate. No secret in any file the agent can read. Nothing to install. Filter. Maskit (AGPL) swaps secrets and personal data for placeholders before the request leaves. What remains. A key in a format the filter does not know leaves as is.