Mac で Claude Code を始める — インストールから subagent / MCP / hook まで（2026 年版） Mac で Claude Code を始める — インストールから subagent / MCP / hook まで（2026 年版）

Claude Code has changed substantially between late 2024 and 2026, and anyone returning to it after a long break may not recognize the tool. What started as a terminal-based chat assistant has grown into a coordinated development environment built around three core ideas: subagents that split work across specialized roles, the Model Context Protocol (MCP) for connecting external tools and data, and hooks that automate steps in the coding loop. For Mac users in particular, the setup path has become smoother, and understanding these pieces matters because they define how the tool actually fits into a real workflow rather than acting as a novelty.

Installation on macOS is the natural first step. Claude Code typically runs as a command-line tool, so you start from the Terminal and authenticate against an Anthropic account or API key. Most users install via npm or a provided installer script, then run an initialization command inside a project directory. From there, Claude Code reads the local files, builds context, and lets you describe changes in natural language while it edits, runs, and verifies code on your behalf. The experience is closer to pair programming than to copy-pasting from a chat window, which is the main reason it has gained traction with developers who previously used web-based assistants.

The most visible evolution is the subagent model. Rather than one assistant trying to do everything, you can define agents with distinct responsibilities, such as one that focuses on writing tests, another that reviews code, and another that handles documentation. Each subagent operates with its own context and instructions, which appears to reduce confusion on larger tasks and keeps the main conversation cleaner. This mirrors a broader industry direction toward multi-agent orchestration, where a coordinator delegates to specialists. The trade-off is added complexity in configuration, so newcomers are generally advised to start with a single agent before splitting roles.

MCP is the second pillar and arguably the most consequential for integration. The Model Context Protocol is an open standard, introduced by Anthropic in late 2024, that lets AI clients talk to external servers exposing tools, files, and APIs in a consistent way. By configuring MCP servers, Claude Code can reach databases, issue trackers, browsers, or internal services without bespoke glue code for each one. The protocol has been widely adopted across editors and assistants, and many community-built servers exist for common platforms. On a Mac, setup usually involves editing a configuration file that lists the servers and their startup commands, after which the tools become available inside sessions.

Hooks round out the picture by letting you run custom scripts at defined points, such as before a commit, after a file edit, or when a task completes. This is where Claude Code starts to resemble a programmable build system: you can enforce linting, trigger tests, or block unsafe actions automatically. Used well, hooks reduce manual review and create guardrails, which is increasingly important as agents take more autonomous actions. Used carelessly, they can cause unexpected behavior, so testing them in a sandbox is sensible.

Context for newcomers helps here. Claude Code competes with and complements tools like GitHub Copilot, Cursor, and the various open-source agent frameworks, and the lines between them keep blurring as MCP support spreads. Subscription tiers, model availability, and rate limits change frequently, so pricing and exact capabilities should be checked against current documentation rather than assumed. Anyone evaluating these tools should also weigh data handling, since granting an agent access to repositories and external systems carries real security and compliance considerations.

Practically, a reasonable path is to install the tool, run it on a small project, and rely on plain conversation before layering on advanced features. Add one MCP server when you have a concrete integration need, define a subagent once a task clearly splits into roles, and introduce hooks only after the basics feel reliable. This staged approach avoids the common mistake of configuring everything at once and then struggling to debug. As of 2026, Claude Code is best understood not as a chatbot but as an extensible agentic platform, and the Mac setup is mostly about wiring these components together thoughtfully.