Cheatsheet
Purpose: A one-page reference for the things you'll do most often. Common AI prompts, git basics, deploy commands, token discipline. The goal is "I forgot how to do X — let me grab it from one place." Lessons link here for re-discoverable commands.
Structure: Four sections. Each entry is a tight one-liner with a one-line "why" comment.
How to contribute: See CONTRIBUTING.md. When you author a lesson that introduces a re-usable command or prompt, add it here in the same PR. Keep entries terse — this is a reference, not a tutorial.
AI prompts
Plan: I want to {feature}. The constraints are {list}. The current state is in {files}. Don't write code yet.
Use to start a planning conversation. Module 3 covers the four-step prompt template (intent / constraints / context / ask) in depth.
/clear
Reset Claude Code or Gemini CLI conversation history. Use between unrelated tasks; cuts token cost on the next prompt.
/context
Show how much of your context window is in use (Claude Code). Watch this when you're on Path 2 (Gemini CLI free tier — use /stats there) or Path 3 (Anthropic API token-careful) — see BUDGET.md.
/cost
Show running session spend (Claude Code). Path 3 learners check this regularly.
AI agent install + hygiene
curl -fsSL https://claude.ai/install.sh | bash
Install Claude Code on macOS or Linux. Re-check VERSIONS.md for the latest verified command.
irm https://claude.ai/install.ps1 | iex
Install Claude Code on Windows (PowerShell).
npm install -g @google/gemini-cli
Install Gemini CLI on any platform with Node 20 or newer.
claude --version
Confirm Claude Code installed (Path 1 or Path 3).
gemini --version
Confirm Gemini CLI installed (Path 2).
Hygiene templates ship at thread-project-template/ — copy into a new project so AI agents skip secrets, planning notes, and dependency folders by default. See Module 2 Lesson 6.
Terminal basics
pwd
Print working directory — where am I? Run this when you've been cd-ing around and lost track.
ls
List files in the current directory. Add a path to peek into a folder without cd-ing into it: ls modules.
cd <directory>
Change into a directory. cd .. moves up one level; cd alone goes home.
clear
Wipe the visible terminal output. Cosmetic — your command history is still there (up arrow).
mkdir <name>
Make a new (empty) directory. Errors if the directory already exists.
rmdir <name>
Remove an EMPTY directory. Safer than rm -rf for cleanup; errors if the directory isn't empty.
Runtime + tooling
node --version
Print the installed Node version. Sanity check after opening a fresh Codespace; this course pins Node 20.x LTS (see VERSIONS.md).
node
Open Node's REPL (interactive prompt). Type JavaScript expressions and see results; .exit to leave.
node <file.js>
Run a JavaScript file directly with Node. Module 4 onward, you'll mostly use npm run dev instead — the project scaffold wires this up for you.
Package management
npm --version
Print the installed npm version. Sanity check after opening a fresh Codespace — npm and Node ship together but are separate tools, so their version numbers differ. This course pins npm 10.x (bundled with Node 20.x LTS, see VERSIONS.md).
npm install
Read package.json and download every dependency into node_modules/. The first command to run after cloning a fresh project that uses npm.
npm install <package-name>
Add a new package to dependencies AND download it. Example: npm install date-fns.
npm uninstall <package-name>
Remove a package from dependencies AND delete it from node_modules/.
npm run dev
Start the development server defined in package.json's scripts.dev. Module 4 onward, you'll run this every day to see your app live in the browser preview.
Git basics
git status
Show what's changed but not committed. Run before every commit.
git add . && git commit -m "describe what changed"
Stage and commit everything. Default rhythm in Codespaces.
git push
Send your commits to GitHub. Push frequently — Codespaces lose your work if you delete them without pushing first.
git pull
Fetch commits from a remote host (like GitHub) and merge them into your local copy. Codespaces usually run this automatically when you open them; outside Codespaces, run it at the start of each session if you commit from more than one machine.
git reset --hard HEAD
Throw away ALL uncommitted changes back to your last commit. Use after a bad AI session that broke things. Module 3 covers this as "the undo button when the AI breaks things."
Deploy commands
Phases 3 onward. Phase 1 seeds the section structure; Phase 3 fills in vercel, npx vercel --prod, env-var checklist commands.
Token discipline
/clear
See above — single biggest cost reducer.
/compact
Compress conversation history without losing the gist. Use when context is large but you don't want to lose continuity.
/drop {filename}
Remove a file from the AI's context. Use when the AI keeps editing the wrong file.
/context
Show how much of your context window is in use (Claude Code). Module 3 lesson covers when to act on the number.
/cost
Show running session spend (Claude Code). Path 3 learners check this regularly.
/compress
Gemini CLI's equivalent of Claude Code's /compact — compresses conversation history without losing the gist. Same purpose, different keystroke.
/stats
Gemini CLI's equivalent of Claude Code's /context — show conversation stats including token usage in the current session.
npm vs pnpm note (D-21)
Lessons in this course teach npm (the default package manager for create-next-app; what Claude Code and Gemini CLI reach for by default). The deferred course platform (Phase 01.1, see ROADMAP) uses pnpm for security-cooling reasons. Both work. If you prefer pnpm for the thread project: pnpm install ↔ npm install; pnpm add <pkg> ↔ npm install <pkg>; pnpm run dev ↔ npm run dev. Lessons in M2/M3/M3.5 + the Phase 3 thread project use npm commands verbatim.