🐙 GitHub Copilot: the agent inside the editor you already use

What Copilot is now

Copilot started in 2021 as autocomplete with opinions. In 2026 it’s three products sharing one subscription:

1. Completions — ghost text in the editor, still the thing you’ll use every minute.
2. Chat + agent mode — a panel that can read your workspace, edit multiple files, run terminal commands, and call MCP tools, with your approval.
3. Copilot CLI — the same agent in a terminal, for repos and scripts outside the editor.

The pricing model changed with it: Copilot is now metered in GitHub AI credits rather than “chat requests”. Each plan includes a monthly allowance; heavy agent use burns through it.

Step 1 — Install in VS Code

1. Open VS Code → Extensions view.
2. Install GitHub Copilot (Microsoft) — the Chat extension comes with it.
3. Click the Copilot icon in the status bar → Sign in with GitHub.
4. Authorize in the browser, come back to VS Code.

No subscription? The Free plan activates with your GitHub account. It’s genuinely usable for learning: completions, chat, and agent mode with a monthly credit allowance and automatic model selection.

Step 2 — Switch Chat into agent mode

Open Chat from the Copilot icon, then look at the mode selector at the bottom of the input box:

• Ask — question/answer, reads context, changes nothing.
• Edit — multi-file edits you review as a diff.
• Agent — plans, edits, runs commands, reads output, iterates. This is the one that does work.

In agent mode, every terminal command and file write is proposed first. You approve, skip, or edit. Approval fatigue is the real risk — after the tenth npm test it’s tempting to hit “always allow”. Don’t do that for anything that writes outside the repo.

Two settings worth knowing:

• Custom instructions: .github/copilot-instructions.md at the repo root is read automatically. Put your conventions there, not in chat.
• MCP servers: Copilot can call external tools (databases, browsers, issue trackers) through MCP. Start with one, not five. What MCP is →

Step 3 — Copilot CLI

For work outside the editor — a server over SSH, a script folder, a CI job:

npm install -g @github/copilot      # Node.js 22+

winget install GitHub.Copilot       # Windows

brew install --cask copilot-cli     # macOS / Linux

First run:

cd ~/projects/my-app
copilot
/login          # authenticate with GitHub, once

Then just ask. Shortcuts that matter: @ to mention files, / for slash commands, ? for help, Esc to cancel, Ctrl+C to clear or exit.

Non-interactive, for scripts:

copilot -p "explain what this repo does"
copilot -sp "list the TODO comments in src/"   # -s: response only, no usage noise

Step 4 — Which plan, really

Prices as of November 2026, per user per month:

A credit is not a request: a long agent turn with a big model can cost many credits, a completion costs a fraction. The practical rule: start on Free, move to Pro the first month you hit the cap, and only consider Pro+ if you’re in agent mode most of the day.

Copilot vs. Cursor vs. Claude Code

If your team already pays for GitHub, Copilot is the least-friction choice and the one your security team has already reviewed. If you live in a terminal, the CLI is good but Claude Code and Codex CLI are more capable there.