---
title: "How to Use Claude Code to Write and Debug Python – Real Python"
url: https://daily.dev/posts/how-to-use-claude-code-to-write-and-debug-python-real-python-dgkaybt5v
source_url: https://realpython.com/how-to-use-claude-code
type: article
source: "Real Python"
published: 2026-08-19T14:02:51.956Z
updated: 2026-08-19T14:05:52.954Z
tags: ["python", "testing", "ai-agents", "claude-code"]
reading_time: 25
upvotes: 2
comments: 0
language: en
---

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

# How to Use Claude Code to Write and Debug Python – Real Python

**[Real Python](https://daily.dev/sources/rpython)** · 25 min read · 2 upvotes · 0 comments

## Summary

A hands-on tutorial walks through installing and configuring Claude Code, then using it to build a command-line contact manager in Python from scratch. It covers permission modes (manual, accept edits, plan, auto), writing a CLAUDE.md conventions file, plan-first workflows, reviewing diffs, generating tests with unittest, and committing with Git. A second half demonstrates using Claude Code to explore an unfamiliar codebase, find bugs (a TypeError crash on malformed CSV rows, concurrent write corruption, newline rendering issues, and silent empty-string acceptance), and fix them. Ends with troubleshooting tips and an FAQ on installation, cost, and safety.

## Full article

daily.dev links to this article rather than hosting it. Read it at the original source: <https://realpython.com/how-to-use-claude-code>

## Questions this post answers

### What are the different permission modes in Claude Code and what does each one do?

Claude Code cycles through four permission modes via Shift+Tab: Manual pauses for approval before every edit, command, or network request; Accept Edits applies edits automatically for review afterward with git diff; Plan researches and proposes changes without editing files; Auto runs actions it judges safe, blocks risky ones, and looks for safer alternatives. Bypass permissions and dontAsk modes are also available via flags or settings.

_daily.dev surfaces workflow guides like this for developers tuning how much autonomy to give coding agents._

### How do I stop Claude Code from crashing when reading a CSV row with missing fields?

Configure csv.DictReader with restval="" instead of its default of None, so missing fields are filled with an empty string rather than None. Without this, calling len() or ljust() on a None value in a table-formatting function raises a TypeError when a CSV row has fewer columns than the header.

_Developers debugging CSV parsing edge cases can find fixes like this by following python troubleshooting content on daily.dev._

### Does Claude Code require Node.js or npm to install?

No, the native installer for Claude Code is a self-contained binary with no Node.js, global npm packages, or version manager required. An older npm-based install path still exists but is no longer the recommended option; the native installer handles auto-updates automatically once installed.

_daily.dev helps developers weighing setup friction across ai coding tools before adopting one._

## Similar posts on daily.dev

- [Getting Started With Claude Code – Real Python](https://daily.dev/posts/getting-started-with-claude-code-real-python-cicd5aptg) · Real Python · 0 upvotes · 0 comments
- [How to Write a CLAUDE.md File for Claude Code – Real Python](https://daily.dev/posts/how-to-write-a-claude-md-file-for-claude-code-real-python-qmsfwtb2t) · Real Python · 2 upvotes · 0 comments

---

Tags: [#python](https://daily.dev/tags/python), [#testing](https://daily.dev/tags/testing), [#ai-agents](https://daily.dev/tags/ai-agents), [#claude-code](https://daily.dev/tags/claude-code)

[View this post on daily.dev](https://daily.dev/posts/how-to-use-claude-code-to-write-and-debug-python-real-python-dgkaybt5v)