Claude Code

Claude Code is Anthropic’s coding assistant that runs in your terminal. It can read files, edit code, run commands, and iterate on a task until you stop it or it finishes.

What It Does Well

Claude's capabilities

How It Works

Claude Code follows an agent loop: gather context, take action, verify, repeat.

flowchart TD
    A["You send a prompt"] --> B["Gather context"]
    B --> C["Take action"]
    C --> D["Verify results"]
    D --> E{"Done?"}
    E -->|No| B
    E -->|Yes| F["Return final result"]

In practice, that means it may search files, inspect code paths, edit files, run tests, and then iterate.

Context Gathering

Claude Code usually explores a codebase on demand using file search and reads, then loads what it needs into context. It is not limited to a pre-selected set of files.

Claude Code context gathering

Built-in Tool Categories

Category	Examples
File operations	Read, create, edit, rename files
Search	Find files, grep/regex style lookup
Execution	Run tests, scripts, git commands
Web	Look up docs or troubleshooting info
Orchestration	Use subagents for parallel work

Common Use Cases

Use case	Example prompts
Codebase orientation	”Explain auth flow in this repo”
Feature work	”Add rate limiting to this endpoint and add tests”
Debugging	”Investigate this stack trace and fix root cause”
Refactoring	”Rename this API and update all references”
Review support	”Review this diff for regressions and missing tests”

Memory And Project Instructions

Claude Code uses two memory layers:

CLAUDE.md files that you write (project/team/user guidance)
Auto memory that Claude writes based on repeated corrections/preferences

Where `CLAUDE.md` can live

CLAUDE.md file locations

Claude also loads CLAUDE.md and CLAUDE.local.md files while walking up the directory tree from your current working directory, and can load subtree-specific guidance when working in those folders.

Useful commands for memory/context

Need	Command
Create starter project guidance	`/init`
View/edit loaded memory files	`/memory`
Start fresh conversation	`/clear`
Compact long history	`/compact`
Resume older conversation	`/resume`

MCP (Model Context Protocol)

Claude Code supports MCP for connecting tools and data sources (issue trackers, docs, databases, monitoring systems, etc.).

# Local stdio server
claude mcp add my-server -- /path/to/server

# Remote HTTP server
claude mcp add --transport http my-server https://example.com/mcp

# Remote SSE server
claude mcp add --transport sse my-server https://example.com/sse

Use /mcp inside Claude Code to manage connections and authentication.

Installation

As of April 20, 2026, Anthropic recommends native installers first.

# macOS / Linux / WSL (recommended)
curl -fsSL https://claude.ai/install.sh | bash

# Windows PowerShell (recommended)
irm https://claude.ai/install.ps1 | iex

# Alternatives
brew install --cask claude-code
winget install Anthropic.ClaudeCode

npm install -g @anthropic-ai/claude-code still exists for compatibility, but it is no longer the primary recommendation.

Then start in your project:

claude

Access And Cost Notes

Pricing and plan details change often, so avoid hard-coding numbers in docs.

As of April 20, 2026:

The free Claude.ai plan does not include Claude Code access
Access is available via paid Claude plans or Anthropic Console/API billing
Team and enterprise usage is generally usage-based and policy-controlled
Check the official pricing page for current limits and cost details

Slash Commands

Command availability can vary by version, platform, and plan. Use /help for the exact list in your installed version.

Common commands:

Command	Purpose
`/help`	List available commands
`/init`	Generate or improve project `CLAUDE.md`
`/model`	Select model
`/memory`	Manage memory files and auto memory
`/mcp`	Manage MCP servers/auth
`/clear`	Start a fresh conversation
`/compact`	Reduce context usage
`/review`	Run code review workflow
`/rewind`	Rewind session/code state
`/doctor`	Diagnose installation/setup
`/cost`	Show token-cost estimates (especially for API usage)
`/stats`	Show usage patterns

Custom Commands

You can create reusable project or user commands with markdown files.

Project scope: .claude/commands/
User scope: ~/.claude/commands/

Example:

Review the current branch diff against main.
List likely bugs, missing tests, and risky changes.
Suggest concrete fixes.

Run it in-session as:

/fix-pr

VS Code Integration

The VS Code extension adds a UI on top of Claude Code with:

Inline diff review before applying edits
Accept/reject controls for proposed changes
File @ mentions (including line ranges)
Plan review and conversation history in-editor

When To Use Claude Code

Good fit	Better alternative
Multi-step coding tasks across files	Single quick Q&A without code changes
Debugging with logs/tests/commands	Tasks where terminal access is not appropriate
Repo-wide refactors or cleanup	Workflows requiring strict manual-only editing
Repetitive engineering chores	One-off tasks easier done directly in IDE

Quick Summary

Claude Code is a terminal-first coding assistant with tool use
It works iteratively: inspect, change, verify, repeat
CLAUDE.md and auto memory provide persistent context
MCP extends it to external tools and systems
Installer and command surface evolve quickly, so verify with official docs