Copilot CLI, PR Summaries, and Code Review

Copilot is not only for writing new code in your editor. It extends into the terminal, pull requests, and code review. These features are often overlooked but can save significant time.

Copilot in the Terminal (Copilot CLI)

GitHub Copilot CLI is a separate tool that brings AI assistance to your terminal. Install it with:

bash
npm install -g @githubnext/github-copilot-cli

After authenticating with github-copilot-cli auth, you get three commands:

gh copilot suggest – Describe what you want to do in plain English and get a shell command:

bash
gh copilot suggest "find all .log files modified in the last 7 days and delete them"
# → find . -name "*.log" -mtime -7 -delete

gh copilot explain – Paste a complex command and get an explanation:

bash
gh copilot explain "awk 'NR==1{print; next} !seen[$0]++' file.txt"
# → Explains that this removes duplicate lines while keeping the first occurrence,
#   preserving the header line (NR==1)

??, git?, gh? shortcuts – Type ?? how do I rebase interactively directly in the terminal.

This is especially useful for:

Complex awk, sed, grep, or find commands you can never remember the exact syntax for
Docker, Kubernetes, and cloud CLI commands
Git operations you use infrequently (rebasing, cherry-picking, bisecting)

Copilot for Pull Requests

When you open a pull request on GitHub.com (requires Copilot subscription), you can use Copilot to:

Auto-generate PR descriptions

Instead of writing a pull request description from scratch, Copilot reads your diff and generates a summary. Click the Copilot icon next to the PR description field. It produces:

A concise summary of what changed and why
A list of changed files with brief descriptions
Sometimes testing instructions

You edit and refine this output — it is a first draft, not a final document. But it saves the "blank page" problem of starting a PR description.

Ask questions about a PR

On any pull request, you can open Copilot Chat and ask questions about the changes:

"What is the purpose of this PR?"
"Are there any potential issues with the changes in auth.ts?"
"Does this change affect backward compatibility?"

Copilot reads the diff and answers based on the actual changes.

Copilot in Code Review

When reviewing someone else's code on GitHub.com, Copilot can help you:

Understand unfamiliar code: Select a block of code in the diff view and ask "Explain what this does." Useful when reviewing code in a language or framework you are less familiar with.

Spot potential issues: Ask "Are there any security concerns with this change?" or "Could this cause a performance issue?" Copilot often catches things like SQL injection risks, missing input validation, or N+1 query patterns.

Suggest improvements: Ask "How could this be simplified?" and use the suggestion as the basis for a review comment.

Important: Copilot is an assistant, not a replacement for careful human review. Use its suggestions as a starting point, then apply your own judgment.

Copilot in GitHub Issues

On GitHub.com, you can mention Copilot in issue comments by typing @github-copilot. It can:

Summarize a long issue thread
Suggest a potential implementation approach
Answer questions about the codebase based on the repository content

Copilot Workspace (GitHub.com)

Copilot Workspace is a feature available on GitHub.com that lets you turn an issue directly into code. The workflow:

Open a GitHub issue describing a feature or bug.
Click "Open in Copilot Workspace."
Copilot reads the issue, explores the repository, and proposes a plan: which files to change and what changes to make.
You review and edit the plan.
Copilot implements the plan — creating or modifying files.
You review the diff, refine, and open a pull request.

This is a full agent loop: issue → plan → code → PR, mostly automated. It works best for well-defined, isolated changes. For complex architectural work, the plan step requires more editing and the output needs more review.