How to set up Claude Code in fifteen minutes, and what to skip

On this page#

• Before you install anything
• The steps
• A working configuration
• Objective
• Before editing
• Repository invariants
• Validation
• Completion
• What to skip
• First real task
• FAQ

Before you install anything#

Set up Claude Code—Anthropic’s coding agent that works from your terminal—in this order: protect the repository, install the official client, authenticate, add repository instructions, inspect its plan, and only then permit edits. The goal is not merely to make Claude Code run; it is to make its first change reviewable and reversible.

Setup order matters because an agent can act faster than you can reconstruct missing context. If you install plugins, grant broad permissions, and start prompting before defining repository invariants, you have created a faster way to make plausible mistakes.

Before installation, confirm four things:

• The repository is under version control.
• The working tree does not contain unrelated changes you could confuse with agent edits.
• The normal test, lint, and type-check commands are known.
• Secrets and generated artifacts are excluded from version control.

Do not begin with global preferences. Begin with the repository. Claude Code needs to know what must remain true in this codebase: architectural boundaries, forbidden files, validation commands, and the expected size of a change.

The official Claude Code documentation explains product operation. It cannot know that your service must preserve an API contract, that migrations require review, or that a generated directory must never be edited. Those constraints belong in the repository.

Photo by Boris K. on Pexels.

The steps#

Use the following sequence and stop if any step cannot be completed cleanly. Each step prevents a distinct failure mode: installing an unofficial package, working in the wrong directory, allowing unreviewed edits, or accepting a change that passes superficial inspection while violating a repository invariant.

1. Open the official installation instructions for your platform.
   This prevents stale commands and unofficial distribution paths. Use only the installation method currently listed in the Claude Code docs.

2. Install Claude Code and complete authentication.
   This prevents you from debugging repository behavior when the actual problem is an incomplete client or account setup.

3. Start Claude Code from the repository root.
   This prevents it from receiving an incomplete view of the project or treating a nested package as the whole system.

4. Ask it to inspect the repository without editing anything.
   This prevents premature changes based on guessed architecture. Have it identify entry points, validation commands, package boundaries, and instruction files.

5. Create a repository-level CLAUDE.md.
   This prevents important constraints from living only in your prompt history. The file should describe durable operating rules, not today’s task.

6. Give it one bounded task and request a plan first.
   This prevents a small request from turning into an unsolicited refactor. Require named files, intended behavior, validation steps, and explicit non-goals.

7. Review the plan before authorizing edits.
   This catches wrong assumptions while they are still cheap. If the plan touches unrelated layers, narrow the task.

8. Review the diff and run the repository’s real checks.
   This prevents “the agent says it works” from becoming your acceptance criterion. Claude Code can assist with validation, but responsibility remains with the engineer.

The official overview is the right reference for capabilities and basic operation. Your repository instructions are the control layer that turns those capabilities into dependable engineering work.

A working configuration#

Start with one concise CLAUDE.md at the repository root. This is a working baseline because it defines evidence, boundaries, and stopping conditions without pretending that configuration can replace review. Paste it as written, then replace only the bracketed placeholders with commands and paths that already exist in your repository.

# Repository operating rules


![Man standing at a whiteboard planning UX design concepts in a modern office setting. — illustrating how to set up claude](/blog/how-to-set-up-claude-code-2.jpg)
*Photo by Christina Morillo on [Pexels](https://www.pexels.com/photo/man-wearing-blue-dress-shirt-facing-whiteboard-1181343/).*

## Objective
Make the smallest correct change that satisfies the requested behavior.

## Before editing
- Read the relevant implementation, tests, and nearby documentation.
- State the proposed files to change and why.
- Identify any assumption that is not confirmed by repository evidence.
- Do not edit until the plan is internally consistent.


![A close-up shot of a person coding on a laptop, focusing on the hands and screen. — illustrating how to set up claude co](/blog/how-to-set-up-claude-code-3.jpg)
*Photo by Lukas Blazek on [Pexels](https://www.pexels.com/photo/person-encoding-in-laptop-574071/).*

## Repository invariants
- Preserve public interfaces unless the task explicitly requires a change.
- Do not weaken tests, validation, authentication, or authorization.
- Do not edit generated files: [GENERATED_PATHS].
- Do not read, print, copy, or modify secrets.
- Do not add dependencies unless they are necessary and explicitly approved.
- Keep unrelated formatting and refactoring out of the diff.

## Validation
- Tests: [TEST_COMMAND]
- Lint: [LINT_COMMAND]
- Type check: [TYPECHECK_COMMAND]
- Build: [BUILD_COMMAND]

## Completion
- Run the relevant validation commands.
- Summarize changed files and observable behavior.
- Report any command that was not run and why.
- List remaining risks or unverified assumptions.

Here is what each part does:

• Objective blocks unnecessary redesign by defining “smallest correct change” as the default.
• Before editing forces repository inspection and makes unsupported assumptions visible.
• Repository invariants records rules that must survive across tasks and sessions.
• Validation replaces vague requests such as “check your work” with the repository’s actual commands.
• Completion prevents a confident summary from hiding skipped checks or unresolved risk.

Do not paste invented commands into the placeholders. If the repository has no documented type-check command, write Not configured instead of guessing. That absence is useful information.

This file is deliberately short. A giant instruction file becomes background noise and accumulates contradictions. For a fuller operational system covering task framing, review boundaries, and reusable agent instructions, use the PairFoundry Agent Operating Kit. The point is repeatable control, not more prose.

What to skip#

Skip anything that increases surface area before your first controlled change. A clean installation, a repository instruction file, and one real task are enough to evaluate Claude Code. Extra agents, elaborate hooks, broad permissions, and copied “ultimate configs” make failures harder to attribute and rarely improve the first result.

| Common tutorial step | Why to skip it | |---|---| | Installing every integration immediately | You cannot tell which component caused a failure. | | Granting blanket command approval | Convenience is not a substitute for reviewing consequential actions. | | Copying a huge generic CLAUDE.md | Generic rules crowd out repository-specific invariants. | | Creating multiple specialized agents | Coordination overhead appears before the workflow is proven. | | Adding hooks before understanding the base loop | Automation can repeatedly enforce the wrong assumption. | | Asking Claude Code to “improve the codebase” | The task has no boundary, acceptance test, or defensible stopping point. | | Treating generated summaries as verification | A summary is a claim; tests and diffs are evidence. |

Also skip cosmetic personalization until the core loop works. Themes, aliases, prompt collections, and elaborate status displays do not protect production code.

If your team is still learning how to frame tasks and define acceptance criteria, use the free PairFoundry foundations track. If you already know the gap you need to close, compare the available PairFoundry packs. Additional setup articles belong in the agent setup hub.

First real task#

Choose a small defect with an existing failing test—or behavior that can be captured by one—and ask Claude Code to diagnose it before editing. The task should cross enough code to expose its reasoning, yet remain narrow enough that you can independently review every changed line and verify the outcome.

A good first prompt is:

Inspect this repository and diagnose [SPECIFIC DEFECT].

Do not edit files yet. First:
1. Identify the relevant execution path.
2. Name the files you expect to change.
3. Explain the likely cause using repository evidence.
4. Propose the smallest fix.
5. State which existing checks you will run.
6. State whether a focused regression test is needed.

Do not refactor unrelated code, add dependencies, or change public interfaces.
Wait for approval before editing.

After approving the plan, ask it to implement only that plan. Reject additional cleanup unless it is required for correctness.

Your acceptance sequence is simple:

1. Inspect the diff.
2. Confirm the change matches the approved scope.
3. Run the focused test.
4. Run the relevant broader checks from CLAUDE.md.
5. Ask for remaining risks and unverified assumptions.
6. Commit only after you understand the change.

Do not make a repository-wide migration the first task. A migration combines discovery, design, repetitive edits, compatibility decisions, and validation. When it fails, you learn almost nothing about which part of the setup was wrong.

Related reading#

• How to setup Claude Code: the order matters more than the settings
• Claude Code guide — what to do before you type a single prompt

FAQ#

How should I setup the Claude Code?#

Install it using the current official instructions, authenticate, launch it from the repository root, and ask it to inspect without editing. Then add a concise CLAUDE.md, assign one bounded task, review its plan, authorize the smallest change, inspect the diff, and run the repository’s real validation commands.

Can I set up a Claude Code for free?#

You can prepare the repository-side setup—version control, CLAUDE.md, invariants, validation commands, and task templates—without buying a configuration product. Access and usage terms for Claude Code can change, so use Anthropic’s official overview rather than relying on an old tutorial’s pricing claim.

How to create your own Claude Code?#

You do not need to create a separate coding agent to get repository-specific behavior. Configure Claude Code with a root-level CLAUDE.md that records your project’s boundaries, commands, and completion criteria. Keep task-specific requirements in the prompt, and keep durable engineering rules in the repository file.

How to get Claude Code?#

Get Claude Code only through the installation path listed in the official documentation. Avoid copied installer commands from undated posts because distribution methods can change. After installation, complete authentication, enter a real repository, and verify read-only inspection before asking it to modify files.

Is the Claude Code free?#

Do not assume that installation, account access, and model usage have the same cost conditions. Check the current terms linked from Anthropic’s official Claude Code documentation. Regardless of cost, the repository configuration described here requires no paid template: it is a plain, version-controlled Markdown file.