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Join us for Rubber Duck Thursdays! A lighthearted and informal stream where we live code on some projects. This week we explore how to bring the power of GitHub Copilot into your apps with the GitHub Copilot SDK, building hands-on examples and discussing patterns for integrating AI-powered coding assistance directly into developer tools and workflows.

AI-powered coding practice platform built with the GitHub Copilot SDK. Personalized challenges, real-time evaluation, and learning guidance based on your GitHub profile.

Learn how I managed context to keep Copilot focused, used the Plan agent to sharpen vague requirements, and required Test Driven Development practices to catch bugs before users.

A countdown app where every countdown is a URL. Create custom countdowns, timers, and world clocks for any occasion with multiple visual themes and instant URL sharing.

Chris showcases Timestamp, an open-source countdown timer app built with vanilla TypeScript featuring an extensible theme system, world map wall clock, and 2500+ unit tests with 300+ Playwright end-to-end tests. He deep-dives into structuring GitHub Copilot custom instructions vs agents vs prompt files, demonstrates manager-specialist agent patterns, and walks through GitHub Actions automation for issue forms and theme scaffolding.

Quoted as a GitHub expert on the importance of integrating security tooling into development lifecycle and the role of AI in secure coding practices.

Chris builds a New Year countdown app from scratch using Vite, TypeScript, and Tailwind CSS, leveraging GitHub Copilot's Plan agent for iterative requirements and a custom UI Performance Specialist agent. The stream covers adding time zone support with a world map, a fireworks celebration theme using fireworks.js, and a test-driven development approach.

Chris reviews the latest GitHub changelog including CodeQL updates, GPT-5.1 Codex Max preview, GitHub MCP server tool-specific configuration, and Enterprise Server 3.19 GA. He then explores the major VS Code December release featuring Agent HQ, background agents with git worktrees, sub-agents, and custom agents for organizations, while continuing to build custom agents for a game MCP server project.

Chris continues building custom agents for the software development life cycle. After reviewing the changelog including Copilot Spaces updates and assigning issues to Copilot via API, he explores the awesome-copilot repository for agent inspiration, brainstorms SDLC agent ideas like test writers and security reviewers, and live-builds a GitHub Actions workflow agent with a companion instructions file.

Chris dives into Copilot custom agents and custom instructions for the turn-based game MCP server project. After reviewing the changelog including enterprise bring-your-own-key support and Claude Opus 4.5, he restructures copilot-instructions.md, creates meta instruction files for writing instructions and agents, and explores plan mode for iterating on agent designs.