> ## Documentation Index
> Fetch the complete documentation index at: https://docs.llmeasy.ru/llms.txt
> Use this file to discover all available pages before exploring further.

# What Is Claude Code and How Does It Work?

> Learn what Claude Code is, how it works with a codebase, and how context, tool permissions, MCP, and API providers fit together.

## Quick answer

Claude Code is a coding agent for software development. It is not just a chat page. It can read a codebase, edit files, run commands, and help with development tasks from a terminal, IDE, desktop app, or browser.

The basic workflow is: Claude Code reads project context, plans the task, calls tools, edits files, and runs checks when needed. It is designed for multi-file changes, test fixes, code review, scripts, and longer engineering tasks.

The model API only handles inference. Local permissions, file access, command execution, hooks, and MCP tools are still controlled by Claude Code and your project setup.

## When this matters

* You are installing Claude Code for the first time
* You want Claude Code to modify a local repository
* You are trying to understand why it reads files or uses many tokens
* You plan to connect a custom API Key and Base URL
* You are choosing between Claude Code, Claude Desktop, Cursor, and Codex CLI

## Key concepts

| Concept           | Meaning                                                                                    |
| ----------------- | ------------------------------------------------------------------------------------------ |
| Coding agent      | A development-focused agent that can inspect code, use tools, edit files, and run commands |
| Working directory | The project directory Claude Code can inspect and modify                                   |
| Tool use          | File reads, code search, file edits, shell commands, and similar actions                   |
| Context           | Conversation history, files, project rules, `CLAUDE.md`, and tool results                  |
| MCP               | A protocol for adding tools and data sources; it is not the model API                      |
| `CLAUDE.md`       | A project instruction file Claude Code can load as context                                 |

## Recommended workflow

1. Start Claude Code from a real project directory.
2. Ask it to inspect the relevant files before making broad edits.
3. For complex work, ask for a plan before implementation.
4. Let it change a small set of files, then run the fastest relevant check.
5. Put stable project rules in `CLAUDE.md`; keep one-off instructions in the conversation.

If you connect Claude Code through an API gateway, confirm that the endpoint is Anthropic-compatible. In this documentation, Claude Code uses `https://www.llmeasy.ru`. Do not use the OpenAI-compatible `https://www.llmeasy.ru/v1` in Claude Code's Anthropic protocol configuration.

## Common mistakes

* Treating Claude Code like a normal chat page and forgetting that it can touch local files.
* Expecting it to understand the whole repository without reading files or project instructions.
* Treating MCP as a model API. MCP adds tools; API Key, Base URL, and Model ID configure inference.
* Mixing Claude.ai login, Claude Console API, and third-party API gateways.
* Allowing broad local execution without review, tests, or command boundaries.

## About LLMEasy

When Claude Code uses a custom API Key and Base URL, it can send model requests through an Anthropic-compatible API gateway. LLMEasy belongs to that model API layer and can help manage API Keys, balance, and usage history.

LLMEasy does not replace Claude Code permissions, file access controls, hooks, MCP config, or project rules. Those remain part of the Claude Code workflow.

## Related docs

* [Claude Code setup guide](/en/ai-tools/claude-code)
* [Does Claude Code use a Claude.ai account or an API Key?](/en/faq/claude-code/claude-account-or-api-key)
* [How to configure API Key and Base URL in Claude Code](/en/faq/claude-code/api-key-base-url)
* [What is CLAUDE.md in Claude Code?](/en/faq/claude-code/claude-md)

## References

* [Claude Code overview](https://docs.anthropic.com/en/docs/claude-code/overview)
* [Claude Code quickstart](https://docs.anthropic.com/en/docs/claude-code/quickstart)
* [How Claude remembers your project](https://docs.anthropic.com/en/docs/claude-code/memory)