---
title: What Claude Code is — Claude basics, lesson 1
description: Claude Code is Claude working on your computer: it reads files, writes files and runs commands in a loop you can stop or steer. Lesson 1 of Claude basics.
url: https://instibrain.ai/guides/claude-basics/what-claude-code-is
updated: 2026-10-28
site: https://instibrain.ai/llms.txt
---

lesson 1 of 7 · claude basics

# What Claude Code is.

Claude Code is Claude working on your computer. It reads files, writes files and runs commands for you.

## new words

**Terminal**
A window where you type instead of clicking.

**Prompt**
The line at the bottom of the window where you type to Claude.

**Session**
One conversation, from the moment Claude starts until you close it.

## the lesson

You give Claude a task in plain English. Claude works in a loop. It looks around to understand the task, it acts, and it checks the result. It repeats until the task is done.

You stay in charge the whole time. Press Esc to stop Claude; it keeps the work done so far. To steer it, type a note and press Enter while it works. Claude reads the note at its next step.

The same Claude Code runs in a terminal, in VS Code, in the Claude desktop app and at claude.ai/code. The instibrain button opens it in a terminal window.

| Key | What it does |
| Enter | Sends your message. |
| Esc | Stops Claude. The work done so far stays. |
| Esc twice, on an empty prompt | Opens a menu that goes back to an earlier point in the session. |
| Ctrl + C twice, when Claude is idle | Closes Claude. |

One task, many rounds. Claude decides each next step from what the last step showed.

## try it

Click the instibrain button. Choose Fresh session and press Enter. Then type this and press Enter:

```
What can you do on this computer? Answer in three short lines.
```

## you should see

- Three short lines from Claude.
- Under the prompt, a short line names the permission mode. A new session says `auto mode on`. Lesson 6 explains it.

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