GitLab Duo

## What It Does

GitLab Duo embeds AI assistance across GitLab itself rather than as a separate tool: inline code completion while writing, a chat assistant (Duo Chat) that can explain code, refactor, generate tests, or answer questions about a project, and AI-generated summaries for merge requests, code reviews, and security vulnerabilities.

## Key Features

- **Code Suggestions**: Inline, context-aware code completion as you type, across supported languages and IDEs. - **Duo Chat**: A conversational assistant inside GitLab that can explain unfamiliar code, suggest fixes, generate tests, and answer questions using project context. - **Merge request summaries**: Auto-generated summaries of what changed and why, to speed up code review. - **Vulnerability explanation**: Summarizes and suggests remediation for security findings surfaced by GitLab's scanners. - **Root cause analysis**: Helps diagnose CI/CD pipeline failures.

## Who It's For

Teams already using GitLab for source control, CI/CD, and issue tracking who want AI assistance without adopting a separate coding-assistant tool and its own auth/context setup.

## Practical Tips

- Duo Chat's answers are strongest when scoped to a specific file, merge request, or issue rather than asked generically. - Enterprise-tier features (broader vulnerability analysis, custom models) require the higher Duo add-on tier.

## Limitations

Full Duo Enterprise features require GitLab Ultimate or the Duo Enterprise add-on; the free Duo Core tier only covers a subset of capabilities.