G
GitHub
Where code lives and changes are reviewed. Also the place most AI coding agents deliver their work, as pull requests.
01 · Introduction
What GitHub is
Git keeps a history of every change to a set of files. GitHub is a website that hosts those histories and adds the teamwork around them.
The words you will meet:
- Repository (repo): one project and its full history.
- Commit: one saved change with a message saying why.
- Branch: a side copy where you work without touching the main version.
- Pull request (PR): "here is my branch, please review and merge it". This is where discussion and review happen.
- Issue: a ticket for a bug or a task.
- Actions: automation that runs when something changes, for example tests on every pull request.
AI coding agents (Codex, Claude Code, Copilot) read a repository and deliver their work as a pull request, so a little GitHub fluency goes a long way.
02 · When to use it
When you need it
- You work with an AI coding agent and want to see, review and undo its changes.
- A small team shares scripts, prompts or configuration and needs one place with history.
- You want tests or deployments to run automatically when something changes.
- You publish something others may reuse: a tool, a template, a dataset.
03 · Setup
Getting started
- Create an account at github.com and turn on two-factor authentication.
- Install GitHub Desktop (no command line needed) or the
gitcommand. - Create a repository, clone it to your computer, add a file, commit with a message, push.
- Make a branch, change something, open a pull request on the website, merge it.
Do this once with a throwaway project; after that the agents' pull requests will make sense.
04 · How to use it
Day-to-day use
- Read a pull request file by file, not as one wall of green and red. Leave comments on the lines you question.
- Let Actions run the tests on every pull request; a red check is a free reviewer.
- Write commit messages that say why, not what; the diff already shows what.
- Keep secrets out of the repository. Use the repository's Secrets settings for Actions and an
.envfile ignored by git locally. - Copilot (GitHub's own assistant) can review pull requests and suggest fixes inside the website.
05 · Pitfalls
Pitfalls
- A committed API key is public the moment the repository is, and stays in history after you delete it. Rotate it.
- Merging a pull request you did not read is the same as writing the code yourself.
- Force-pushing rewrites history and can erase a colleague's work; avoid it on shared branches.
- Free private repositories have limits on Actions minutes; large test suites can hit them.
06 · Resources
Where to go next
The Skills course and the Copilot pages cover everything a non-developer needs.
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