🧑‍✈️ GitHub Copilot Mastery

• What GitHub Copilot actually is (6 min) — GitHub Copilot is an AI pair programmer built into your editor (VS Code, JetBrains, Visual Studio, Neovim) and into Git…
• Completions: writing with ghost text (7 min) — Completions are the highest-frequency way you'll use Copilot. They read context from your current file, your cursor pos…
• Copilot Chat: slash commands & inline fixes (7 min) — Copilot Chat has two surfaces and a set of slash commands that save you from writing the same prompts repeatedly: **Sur…
• Context is everything: @participants & #variables (8 min) — Context controls answer quality. Copilot gives you explicit handles to supply it: **Participants (@) — bring a domain's…
• Custom instructions: teach Copilot your codebase (7 min) — Custom instructions are how you stop repeating your conventions in every prompt. Copilot reads them automatically and a…
• Agent mode & Copilot Edits: multi-file changes (8 min) — For work that spans files, Copilot has two escalating modes: **Copilot Edits** — you specify a set of files and describ…
• Models & the Copilot coding agent (7 min) — Two things that level up your Copilot use: **Model picker.** Copilot is multi-model — pick from GPT, Claude, and Gemini…
• Copilot in production: security & pitfalls (8 min) — Shipping Copilot-assisted code responsibly comes down to discipline and a few controls: **Review discipline:** every su…

What GitHub Copilot actually is

GitHub Copilot is an AI pair programmer built into your editor (VS Code, JetBrains, Visual Studio, Neovim) and into GitHub.com. It's not one feature — it's three layers: 1. **Completions** — inline 'ghost text' suggestions as you type, accepted with Tab. 2. **Chat** — a conversa…

Completions: writing with ghost text

Completions are the highest-frequency way you'll use Copilot. They read context from your current file, your cursor position, and your other open tabs. To get good ones: • **Comments are prompts.** A precise comment above an empty line steers the suggestion: `// parse the ISO da…

Copilot Chat: slash commands & inline fixes

Copilot Chat has two surfaces and a set of slash commands that save you from writing the same prompts repeatedly: **Surfaces:** the sidebar (project-wide Q&A, keeps conversation history) and inline chat — Cmd/Ctrl+I — which edits the selected code in place and shows a diff you a…

Context is everything: @participants & #variables

Context controls answer quality. Copilot gives you explicit handles to supply it: **Participants (@) — bring a domain's knowledge + tools:** • `@workspace` / `@codebase` — retrieves relevant code from across the repo. Use for 'where/how/why' questions about your codebase. • `@vs…

Custom instructions: teach Copilot your codebase

Custom instructions are how you stop repeating your conventions in every prompt. Copilot reads them automatically and applies them to chat and edits. **Repo-wide:** `.github/copilot-instructions.md` — committed to the repo, so every contributor's Copilot follows the same rules. …

Agent mode & Copilot Edits: multi-file changes

For work that spans files, Copilot has two escalating modes: **Copilot Edits** — you specify a set of files and describe the change; Copilot proposes a coordinated multi-file edit as a reviewable diff set. You accept/reject per file. Great for refactors, applying a pattern acros…

Models & the Copilot coding agent

Two things that level up your Copilot use: **Model picker.** Copilot is multi-model — pick from GPT, Claude, and Gemini variants (plus reasoning models) right in the chat. They differ: some are faster for completions and quick chat, reasoning models are stronger on hard multi-st…

Copilot in production: security & pitfalls

Shipping Copilot-assisted code responsibly comes down to discipline and a few controls: **Review discipline:** every suggestion is a draft. Read it, understand it, and don't accept code you couldn't have written and defended yourself. 'The AI wrote it' is not a code-review answe…