You've probably used ChatGPT or Claude to explain things or draft text. For building, there's more on offer.

Chat apps (ChatGPT, Claude, Gemini)

The easiest place to start.

• Live previews. Ask for an app or a page and it builds it right in the chat. Claude calls these artifacts; in ChatGPT, code blocks have a Preview button. You can click around in it and ask for changes.
• Projects. A shared space for your files and instructions, so every chat in it starts with the same background. Upload ALL-IN-ONE.md here.
• Model picker. You choose which model answers. See Guide 4.
• Extras: web search, file upload, "thinking" or research modes. They're useful, but heavy on usage, so switch them on when you need them.

Coding agents (Claude Code, Codex, Cursor, Claude Cowork, VS Code agents)

These work directly on files in a folder on your computer. They can create and edit files, run things, and fix their own errors. That makes them more powerful, with slightly more setup.

What's different:

• They read an instructions file automatically. AGENTS.md (Codex, Cursor and others) or CLAUDE.md (Claude Code). It's a standing brief the agent reads every session. This pack includes both.
• Plan mode. Many agents can plan without touching anything, then build once you approve. Use it.
• Slash commands. Type / to see your tool's commands, e.g. to clear the chat, compact it (Guide 3), or switch model.
• Permissions. They'll ask before running commands or editing files. Read what they're asking before you approve.
• Subagents. Some can launch separate AI workers for a side job (research, a review), each with its own clean memory. Useful, but one agent is usually enough.
• Checkpoints. Ask the agent to "commit" (save a checkpoint) every time something works, so you can always go back.

What's free (as of 6 Oct 2026; check before relying on it)

• ChatGPT Free includes Codex (the command-line and VS Code versions), with limits.
• Cursor has a limited free tier.
• Claude Code needs a paid Claude plan (Pro, US$20/month).