GitHub Copilot Agents Explained: Build Your Own Custom Agent

GitHub Copilot supports three types of agents: local agents (interactive, workspace-aware), background/CLI agents (autonomous, run in parallel on separate branches), and cloud agents (remote execution on GitHub). Third-party agents like Codex and Claude are also available under one Copilot subscription. Custom sub-agents can be created as markdown files with YAML frontmatter, specifying roles, tools, models, and instructions. These agents can be created manually or generated by Copilot, stored per-project or globally, and used in both VS Code and Copilot CLI. An orchestrator agent can automatically delegate tasks to specialized sub-agents (planner, frontend, backend, tester), each maintaining its own context window for cleaner, more focused execution.