Tutorial: Hardening an AI Agent With Policy Gates, Resource Limits, and Audit Logs

A developer tutorial published on DEV Community details the third security instalment in a series on building a basic AI agent from scratch. The guide focuses on hardening the agent's tool policy gate with three layers: path scoping to prevent file access outside the project directory, a shell denylist to block dangerous commands, and an SSRF guard to stop the agent from reaching internal or private network resources. Additional measures include enforcing resource and cost limits to prevent infinite loops, scrubbing secrets from the container environment, and adding audit logging. A kill switch is also introduced, allowing any agent session to be aborted mid-flight while keeping a full record of every decision made. The work builds on earlier instalments that introduced a Docker sandbox, prompt-injection defenses, and schema validation for tool calls.