Your AI Coding Agent Is Reading Your .env File

In 2026, AI coding agents like Cursor, Claude Code, or Codex have become integral to software development, but they pose a security risk by reading .env files containing plaintext secrets and sending this data to external servers. Traditionally, .env files have been used to manage environment variables due to their simplicity, but they are insufficient for securing sensitive information in the context of AI tools. A better approach involves using runtime secret injection, where secrets are stored externally in a secret store like Infisical and injected into the local development process at runtime, ensuring that they reside in memory rather than in plaintext files. This method not only secures secrets by preventing AI agents from accessing them but also allows seamless integration across various runtimes without modifications. Transitioning to this approach is straightforward and provides a more secure, scalable way to manage secrets in modern development workflows.