Lesson 4. Workflows

Why This Matters#

Claude Code isn’t just “an AI chat.” It’s a full-fledged work tool that can perform real development tasks: finding and fixing bugs, reviewing code, improving project structure, and working with Git. In this lesson, we’ll cover the main workflows — typical scenarios where Claude Code helps the most.

What is a Workflow#

A workflow is a sequence of steps to solve a specific task. For example, “fixing a bug” means: find the error → understand the cause → write a fix → verify everything works.

Claude Code can perform each of these steps — and often the entire chain at once.

Workflow 1: Bug Fixing#

When Needed#

Something isn’t working: the site shows an error, a function returns the wrong result, the program crashes.

How to Work with Claude#

Option A — you know where the bug is:

You: In the file src/cart.js, the calculateTotal function returns
    the wrong sum. The discount isn't being applied. Fix it.

Claude will open the file, find the problem, and suggest a fix.

Option B — you don’t know where the bug is:

You: When a user adds an item to the cart, the total price
    doesn't update. Find and fix the problem.

Claude will analyze multiple files, find the cause, and fix it.

Option C — you have an error message:

You: When running npm start, this error appears:
    TypeError: Cannot read property 'map' of undefined
    at ProductList (src/components/ProductList.js:15)
    Fix it.

Claude will read the error message, open the right file, and fix the problem.

Tips for Bug Fixing#

Give Claude as much context as possible: error text, steps to reproduce
Ask Claude to explain the cause first, then fix it
After the fix, ask to run the tests

Workflow 2: Code Review#

When Needed#

You’ve written code (or Claude did) and want to make sure it’s quality.

How to Work with Claude#

You: Review the file src/auth.js for:
    - Errors and potential problems
    - Security
    - Readability
    - Best practices compliance

Claude will analyze the code and produce a detailed report.

Reviewing Changes Before Committing to Git#

You: Look at my current changes (git diff) and check if
    everything is fine before committing.

Claude will run git diff, analyze all changes, and flag any issues.

Workflow 3: Refactoring (Code Improvement)#

What It Is#

Refactoring means improving code without changing its functionality. The code does the same thing but becomes cleaner, clearer, and easier to maintain. Like a deep cleaning: everything in its place, nothing lost.

How to Work with Claude#

Simplify a complex function:

You: The processOrder function in src/orders.js is too long
    and complex. Break it into several smaller functions.

Update outdated code:

You: Rewrite src/utils.js, replacing old syntax
    with modern JavaScript (ES6+).

Remove duplication:

You: The files src/admin.js and src/user.js have similar code
    for permission checking. Extract the common logic into a separate module.

Workflow 4: Working with Git#

What is Git#

Git is a version control system. It saves the history of all changes in a project, like a “time machine” for code. Key concepts:

Commit — saving changes with a description
Branch — a separate “line” of development
Pull request (PR) — a request to merge your changes into the main code

How Claude Helps with Git#

Creating a commit with a clear description:

You: Look at which files I changed and create a commit
    with a clear description.

Creating a new branch for a task:

You: Create a new branch feature/contact-form and start
    building a feedback form.

Resolving conflicts:

You: I have a merge conflict in src/app.js.
    Help me resolve it.

Typical Git Workflow with Claude#

You: Create branch fix/broken-login

Claude: Created branch fix/broken-login and switched to it.

You: Find and fix the authentication bug — users
    can't log in with uppercase email.

Claude: [finds the problem in src/auth.js, fixes it,
        shows changes]

You: Looks good. Create a commit and describe what was fixed.

Claude: Created commit: "fix: normalize email during
        authentication — convert to lowercase"

Workflow 5: Writing Tests#

What Are Tests#

Tests are special code that verifies your program works correctly. Like a quiz for code: “if the input is 2+2, the output should be 4.”

How to Work with Claude#

You: Write tests for src/cart.js.
    Cover all main scenarios: adding an item,
    removing, calculating discount, empty cart.

Claude will create a test file and can run them right away.

Tips for Effective Work#

✅ Describe tasks at the business logic level: “Users complain that orders aren’t being placed” is better than “Fix line 47”
✅ Ask Claude to explain before it starts changing code
✅ Verify the result: after changes, ask to run tests
✅ Work iteratively: first a small task, then the next one
✅ Use Git: you can always roll back changes if something goes wrong

Lesson Summary#

Claude Code can perform full workflows: bug fixes, reviews, refactoring, Git operations
The more context you provide (error text, files, problem description), the better the result
Claude can work with Git: create branches, commits, resolve conflicts
Always verify the result — ask Claude to run tests or explain the changes
Work step by step: one task at a time