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Glossary

A beginner-friendly reference for all technical terms used in these tutorials.

API (Application Programming Interface)​

A way for software programs to communicate with each other. When you use Claude Code with an API key, your computer sends requests to Anthropic's servers and receives responses — that communication happens through an API.

Agent​

An AI system that can take actions in the real world, not just generate text. Claude Code is an agent because it can read files, write code, run commands, and search the web — not just answer questions.

Branch (Git)​

A parallel version of your project. Branches let you work on new features without affecting the main codebase. Think of it like making a copy of a document to experiment with, while keeping the original safe.

CI/CD (Continuous Integration / Continuous Deployment)​

Automated systems that test and deploy code whenever changes are made. Claude Code can run inside CI/CD pipelines (like GitHub Actions) to automate code review, testing, and other tasks.

CLI (Command-Line Interface)​

A text-based way to interact with your computer by typing commands. Claude Code is a CLI tool — you type instructions and read text responses, rather than clicking buttons in a window.

CLAUDE.md​

A special markdown file that gives Claude Code persistent instructions about your project. It is read at the start of every session and acts as Claude's "memory" of your project's conventions, structure, and rules.

Claude Code​

Anthropic's AI-powered coding assistant that runs in your terminal. It can read and write files, run commands, search the web, and help you with coding tasks through natural language conversation.

Commit (Git)​

A saved snapshot of your project at a point in time. Each commit has a message describing what changed. Commits let you track the history of your project and undo changes if needed.

Context Window​

The amount of text (measured in tokens) that Claude can "see" at once during a conversation. Think of it like Claude's working memory — there is a limit to how much it can hold at one time.

Git​

A version control system that tracks changes to files over time. It is the most widely used tool for managing code history, collaborating with others, and safely experimenting with changes.

Glob​

A pattern-matching syntax for finding files by name. For example, *.md matches all Markdown files, and **/*.js matches all JavaScript files in any subdirectory. Claude Code uses glob patterns with its Glob tool.

Headless Mode​

Running Claude Code without interactive input, using the -p flag. This lets you use Claude in scripts and automation — you provide a prompt, Claude processes it, and returns the result as text or JSON.

Hook​

A custom command that runs automatically at a specific point in Claude Code's lifecycle. For example, you can set up a hook to auto-format code every time Claude edits a file.

IDE (Integrated Development Environment)​

A software application that provides tools for writing code, such as a text editor, file explorer, terminal, and debugger all in one window. VS Code and JetBrains (IntelliJ, PyCharm, etc.) are popular IDEs.

JSON (JavaScript Object Notation)​

A lightweight text format for storing structured data. It uses curly braces {} for objects and square brackets [] for lists. Claude Code's settings files and headless mode output use JSON format.

Markdown​

A simple text formatting language that uses symbols like # for headings, ** for bold, and - for bullet points. CLAUDE.md files, documentation, and these tutorials are written in Markdown.

MCP (Model Context Protocol)​

An open protocol that lets AI models connect to external tools and data sources. MCP servers extend Claude Code's capabilities — for example, connecting to a database, a browser, or a GitHub repository.

Node.js​

A program that lets you run JavaScript outside of a web browser. Claude Code is built with JavaScript and requires Node.js to be installed on your computer. You need the LTS (Long Term Support) version.

npm (Node Package Manager)​

A tool that comes with Node.js for installing JavaScript packages (software libraries). You install Claude Code by running npm install -g @anthropic-ai/claude-code.

PR (Pull Request)​

A request to merge changes from one branch into another, typically on GitHub. Pull requests let others review your code before it becomes part of the main project. Claude Code can create and review PRs.

PowerShell​

A command-line shell and scripting language built into Windows. It is the primary terminal you will use with Claude Code on Windows. Commands in PowerShell start with verbs like Get-, Set-, New-, etc.

Regex (Regular Expression)​

A pattern language for matching text. For example, \d+ matches one or more digits. Claude Code's Grep tool uses regex to search file contents. You do not need to memorize regex — Claude can help you write patterns.

Repository (Repo)​

A folder tracked by Git that contains your project files and their entire change history. When you run git init in a folder, it becomes a repository.

SDK (Software Development Kit)​

A collection of tools, libraries, and documentation for building software. The Anthropic SDK lets developers build applications that use Claude's capabilities programmatically.

Skill​

A reusable workflow or knowledge package in Claude Code. Skills can be built-in (like /commit) or custom (created by you in .claude/skills/). They activate based on context or slash commands.

Subagent​

A secondary AI agent spawned by Claude Code to handle a specific subtask. Subagents have their own context and can work independently, then report results back to the main conversation.

Terminal​

A program that provides a text-based interface for running commands on your computer. On Windows, PowerShell and Command Prompt (CMD) are terminals. Claude Code runs inside a terminal.

Token​

The basic unit of text that AI models process. A token is roughly 3-4 characters or about three-quarters of a word. Costs and context window limits are measured in tokens.

VS Code (Visual Studio Code)​

A free, popular code editor made by Microsoft. Claude Code has a VS Code extension that lets you use Claude directly inside the editor with inline chat and terminal integration.