GitHub Sunsets Copilot Extensions (github.blog)

GitHub is deprecating server-side GitHub Copilot Extensions (built as GitHub Apps) and will disable them on November 10, 2025 at 11:59 PM PST; creation of new server-side Copilot Extensions is blocked after September 24, 2025 (8:00 AM PST) and there will be a brownout testing period November 3–7, 2025. This change does not affect client-side VS Code Copilot extensions or standard GitHub Apps that don’t use Copilot Extension functionality. Copilot Extension–only apps will be removed from the Marketplace; hybrid apps must disable their Copilot Extension configuration before November 10 to remain listed. Private/internal extensions follow the same sunset timeline. The replacement is the Model Context Protocol (MCP): an open, cross-platform standard for AI-agent integration that lets developers build a single MCP server usable across GitHub Copilot, Claude Code and any MCP-compatible host. MCP shifts architectures — enabling autonomous agent tool-calling (Agent Mode/Copilot Coding Agent), individual tool invocation via “#” in IDEs instead of @mentions, modular composability, simplified maintenance, and org-level enable/disable/allowlist controls (per-server allowlists rolling out to IDEs from October 28, 2025). GitHub points developers to the MCP Registry and vendor docs (e.g., Anthropic) to start building; existing Copilot Extensions will stop working on the sunset date and should be replaced with MCP servers rather than migrated.