GitHub Copilot Extensions - AI Developer Tools Tool

Overview

GitHub Copilot Extensions is a public-beta extensibility platform that lets developers build, publish, install, and run integrations inside Copilot Chat on GitHub.com and supported editors. The public beta opened in September 2024, and GitHub published an extensions toolkit that includes documentation, example repositories, an alpha Preview SDK for agent-based extensions, and a CLI debug tool to let you chat with and inspect agents locally. ([github.com](https://github.com/orgs/community/discussions/137975?utm_source=openai)) Extensions can be created as lightweight "skillsets" for simple data retrieval or as full "agents" that control routing, confirmations, and streamed responses; GitHub provides sample repos, the @copilot-extensions/preview-sdk, and a gh debug CLI to simplify development and local debugging. Copilot Extensions run in Copilot Chat across Visual Studio Code, Visual Studio, GitHub.com, GitHub Mobile, Codespaces, JetBrains IDEs, Vim/Neovim, Xcode, and the Copilot CLI (availability depends on client). Copilot Extensions are delivered as GitHub Apps (or IDE chat participants) and are included with Copilot subscriptions. ([docs.github.com](https://docs.github.com/en/copilot/building-copilot-extensions/about-building-copilot-extensions?utm_source=openai)) Important operational note: GitHub has announced that Copilot Extensions implemented as GitHub Apps will be blocked for new creation beginning September 23, 2025 and disabled on November 10, 2025; VS Code-specific Copilot Extensions and other supported integration paths remain supported. Builders should review the changelog and consider alternative MCP/hybrid architectures where needed. ([docs.github.com](https://docs.github.com/en/copilot/building-copilot-extensions/about-building-copilot-extensions?utm_source=openai))

Installation

Install via npm:

npm install @copilot-extensions/preview-sdk --save-dev    # Preview SDK for agent extensions (see repo README). ([github.com](https://github.com/copilot-extensions/preview-sdk.js/))

gh auth login --web -h github.com                        # Authenticate gh CLI (required for gh-debug-cli). ([github.com](https://github.com/copilot-extensions/gh-debug-cli?utm_source=openai))

gh extension install github.com/copilot-extensions/gh-debug-cli    # Install CLI debug tool to chat with an agent locally. ([github.com](https://github.com/copilot-extensions/gh-debug-cli?utm_source=openai))

Install a Copilot Extension from GitHub Marketplace via GitHub.com > Marketplace > Copilot, or publish your GitHub App per docs. ([docs.github.com](https://docs.github.com/en/copilot/how-tos/context/install-copilot-extensions/extending-the-capabilities-of-github-copilot-in-your-personal-account?utm_source=openai))

Key Features

• Agent and skillset extension models: agent = full conversational agent, skillset = lightweight task integrations. ([docs.github.com](https://docs.github.com/en/copilot/building-copilot-extensions/about-building-copilot-extensions?utm_source=openai))
• Preview SDK automates request verification, SSE formatting, and response event creation. ([github.com](https://github.com/copilot-extensions/preview-sdk.js/))
• CLI debugging (gh-debug-cli) to chat locally and inspect SSE events, confirmations, and parsed responses. ([github.com](https://github.com/copilot-extensions/gh-debug-cli?utm_source=openai))
• Marketplace install and org-level controls let organizations publish private or public extensions. ([docs.github.com](https://docs.github.com/en/copilot/how-tos/provide-context/install-copilot-extensions/install-extensions?utm_source=openai))
• Cross-client support: Copilot Chat integrations work in VS Code, Visual Studio, GitHub.com, Codespaces, JetBrains, and more. ([docs.github.com](https://docs.github.com/copilot/how-tos/provide-context/install-copilot-extensions/use-copilot-extensions?utm_source=openai))

Use Cases

• Query monitoring systems (e.g., Sentry) from Copilot Chat and create GitHub issues from findings. ([github.blog](https://github.blog/2024-05-21-introducing-github-copilot-extensions/?utm_source=openai))
• Run retrieval-augmented generation over private docs or knowledge bases with a RAG extension for domain context. ([github.com](https://github.com/copilot-extensions/preview-sdk.js/))
• Automate CI/CD workflows or view deployment status via an Octopus/Azure/CI provider extension inside Chat. ([github.blog](https://github.blog/2024-05-21-introducing-github-copilot-extensions/?utm_source=openai))

Key Information

• Category: Developer Tools
• Type: AI Developer Tools Tool