Context Engineering

Rubber Duck Thursdays - Let's build with custom agents (again!)
GitHubChris 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.

Rubber Duck Thursdays - Let's build with custom agents
GitHubChris 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.

Rubber Duck Thursdays - Let's build
GitHubChris catches up on several weeks of GitHub releases, including new models including GPT-5.1, GPT-5.1 Codex, and GPT-5.1 Codex Mini, MCP registry controls, and isolated sub-agents. He then returns to the turn-based game MCP server project, using Copilot's agent mode to diagnose and fix a dependency upgrade failure.

Rubber Duck Thursdays - Time to build!
GitHubIn this live stream, we explore building a 3D tic-tac-toe visualization using Three.js and Copilot coding agent, demo MCP elicitation for gathering game preferences, and discuss the importance of context engineering when working with AI tools. We also cover GitHub changelog highlights including path-scoped custom instructions for Copilot code review and agents.md support.

Rubber Duck Thursdays - Build for the love of code
GitHubIn this episode, we recap the latest GitHub changelog including GitHub Spark entering public preview and coding agent support for instructions.md files. We introduce the 'Build for the love of code' hackathon, prototype a rubber duck debugging app with GitHub Spark, and build an MCP server from scratch using TypeScript while exploring tools, prompts, and resources.

Rubber Duck Thursdays - Let's build
GitHubIn this stream, Chris catches up on several weeks of GitHub updates including the remote MCP server preview and Copilot coding agent for business users. The live coding session demonstrates adding internationalization to the Copilot Airways app using Copilot coding agent, custom VS Code chat modes for planning, and agent mode in Xcode for iOS development.

Rubber Duck Thursdays - Let's build with agents
GitHubIn 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.

Copilot Agent Mode is now available in GitHub Copilot for Xcode
GitHubGitHub 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.

How to get the most out of the Copilot coding agent
GitHubGetting the best results from the GitHub Copilot coding agent requires deliberate setup across four areas. This video covers writing well-scoped GitHub Issues with clear acceptance criteria and file pointers, crafting Copilot custom instructions to enforce team conventions and development flow, configuring a consistent development environment using Copilot setup steps, and extending Copilot's toolset with Model Context Protocol (MCP) servers configured from repository settings.

Rubber Duck Thursdays - Building from requirements with Agent Mode
GitHubIn 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.