Custom rules in GitLab Duo Agentic Chat for greater developer efficiency

This post introduces custom rules for GitLab Duo Agentic Chat, allowing developers to define specific guidelines for AI-generated code. It covers creating rules in `.gitlab/duo/chat-rules.md` to enforce version control (e.g., Java 8, Python 3 environments), style enforcement (e.g., C goto anti-patterns, VueJS design patterns, Ansible linter compliance), and DevSecOps automation (e.g., project bootstrapping with CI/CD security scanning and documentation standards). It provides practical examples, links to demo projects, and guidelines for rule development, emphasizing iteration and leveraging existing style guides. The post also touches on distribution and testing of custom rules and configuring IDEs for markdown language support in Duo Code Suggestions.