// Testing

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.

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.

In this episode, we review the latest GitHub changelog including remote MCP server support for coding agent and Copilot code review on mobile. We use the Playwright MCP server with Copilot agent mode to debug and fix UI issues in the Octo Arcade project, discuss the differences between ask, edit, and agent modes in VS Code, and explore MCP server concepts like tools, prompts, and resources.

In this episode, we recap the latest GitHub changelog updates including Copilot coding agent availability for pro users and the new Playwright MCP browser capability. We update Copilot custom instructions and setup steps for a GitHub Action project, use the Playwright MCP server to build interactive UI features on a trend radar app, and leverage Copilot coding agent to identify and fix technical debt.

GitHub Copilot for Xcode now supports agent mode alongside the existing ask mode, with full Model Context Protocol (MCP) support for extending Copilot with additional tools. This video walks through toggling between ask and agent modes in the Xcode chat pane, configuring the GitHub MCP server via the Xcode MCP settings tab, and using agent mode to look up and prioritize repository issues. A hands-on demo shows Copilot diagnosing and fixing a premature form validation problem in an iOS app, verified in the simulator.

In this stream, Chris builds a GitHub CLI extension (gh-demo) in Go from scratch using a spec-driven development approach with Copilot Agent Mode. Topics include bootstrapping a VS Code workspace with Copilot, test-driven development for a hydrate subcommand, and setting up GitHub Actions CI.

Building a Rock Paper Scissors game in Go for the gh-game GitHub CLI extension using GitHub Copilot Agent Mode. Explores the new GPT-4o code completion model, Next Edit Suggestions, and drives test coverage from 42% to 100% using Copilot inline chat and agent workflows.

Building on the gh-game CLI extension project, Chris sets up GitHub Codespaces with dev containers, creates a CI workflow using GitHub Actions, and writes Go tests. The stream covers refactoring the coin toss game to use the go-gh prompter package for interactive selection menus, with GitHub Copilot assisting across multiple AI models.

Shows GitHub Copilot Workspace running on the GitHub mobile app, allowing developers to capture ideas and iterate on code from a phone or tablet. The video covers using device dictation for task input, reviewing and editing the AI-generated specification and plan, inspecting code changes via the built-in diff view, running unit tests from the integrated terminal, and creating a pull request with an auto-generated description—all from a mobile device.

Rapid prototyping is more than quick coding — it is a structured discipline for learning fast and making smarter product investment decisions. In this episode, Chris is joined by Andrew Greenstein, CEO of SF AppWorks and host of "The Next Great Thing" podcast, to explore three distinct types of rapid prototyping: design sprints, iterative feature development, and platform proof-of-concepts. The conversation draws on Kent Beck's product development triathlon (explore, expand, extract), Saras Saraswathy's effectuation theory, and a West Elm innovation case study — where rapid prototyping an AI image-matching feature and a chatbot delivered measurable revenue gains.