Installing Claude Code and getting it to actually run

The three things that block a first run: Node version, PATH, and the plan you are signed into.

Claude Code is a command-line tool, not an IDE plugin. Installation is short; the failures are almost always environmental.

1. Node version

It needs a modern Node LTS. If node -v prints something below version 18, upgrade before anything else. The quickest path on macOS or Linux is a version manager (nvm, fnm) rather than a system package, because system packages lag. On Windows, a current LTS from the official installer plus a restart is the reliable route.

2. Install and check PATH

After installing, run the command in a new terminal window. If it says "command not found", the binary went somewhere your shell does not look — usually a global npm directory not on PATH. Fixing PATH is faster than reinstalling, and it is the single most common first-run failure. Check where the package landed before you conclude the installer is broken.

3. Sign in with the right account

The tool uses the subscription you authenticate with. If you have two accounts, check which one is active: open the session, ask it who it is signed in as, or check the account page in the browser. A Max plan on one account does nothing for a session signed into the other.

4. Start inside the repository

Run it from the project root, not your home directory. The agent reads context from where it starts; launching from the wrong folder is why people conclude it "does not understand the project".

5. Give it a task you can verify

A first run should be small: "make this failing test pass", "explain what this module does", "add a flag to this command". Broad requests produce expensive wandering and a bad first impression of a tool that works fine on narrow tasks.

When it runs but says it has no access

This is the follow-up question almost everyone asks, and it is rarely an installation problem. Three checks, in order. First, confirm which account the session is actually authenticated to — the browser and the terminal can end up on different ones. Second, confirm that account holds the paid period: the product is activated on the account whose Organization ID you supplied, not on the email you happen to be reading mail with. Third, distinguish the identifiers: an API key beginning sk-ant- is billing plumbing for the API, not an account identifier, and a subscription on your account does not travel with that key. If a plan is present and healthy but the terminal still refuses, sign out, close the terminal, and complete the browser login once more.

Common failures, ranked

• Old Node — installer fails or the binary exits immediately.
• PATH — command not found in a fresh shell.
• Wrong account — signs in, then reports no access.
• API key pasted as login — authenticates, then sees no subscription.
• Wrong directory — edits files you did not expect.

Once it runs, the limits guide explains why a heavy afternoon stops early, and the plan list shows which tier fits your day. If you want the field it logs in against explained first, what an Organization ID is is the short read.

Common questions

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