Complete GitHub integration for repositories, issues, PRs, workflows, and security. Use when working with GitHub: (1) Repository operations - get/create files, branches, search code, (2) Issue management - list, create, update, comment on issues, (3) Pull requests - create, review, merge PRs, check CI status, (4) GitHub Actions - list workflows, view runs, download logs, trigger workflows, (5) Code security - Dependabot alerts, code scanning, secret scanning. Requires GITHUB_TOKEN environment variable with appropriate scopes.