The Coding Agent That Acts Like a Senior Engineer

If you are a software developer, you have probably used AI chatbots to help write code. You paste a function, ask for a fix, copy the output back into your editor. It works, but it is clunky. You are still doing all the navigation, file management, and integration yourself.

Claude Code is fundamentally different. It is a terminal-based AI agent for coding that operates directly in your codebase. It reads your files, understands your project structure, runs commands, executes tests, and fixes its own mistakes. You give it a goal, and it works through the implementation the way a senior engineer would: methodically, with attention to existing patterns, and with the judgment to ask questions when something is ambiguous.

This is not the same as using a chatbot for code suggestions. Claude Code is an AI agent. It navigates your project, makes changes across multiple files, runs your test suite, and iterates until things work.

This guide covers 10 practical development workflows with prompts you can use directly in this AI agent.

For a broader overview of all agent use cases, check out our complete guide to AI agent use cases.

What You Need Before Starting

This guide uses Claude Code. If you have not set it up yet, start with our setup guide. Claude Code is a terminal-based AI agent designed for developers:

  • Install Claude Code: Available via npm (npm install -g @anthropic-ai/claude-code) or as a standalone CLI. It runs in your terminal, not in a separate application.
  • Anthropic API key or Claude subscription: Claude Code requires authentication with Anthropic.
  • Your codebase: Navigate to your project directory in the terminal and run claude to start a session. Claude Code automatically reads your project structure.
  • No IDE required: Claude Code works in any terminal. It also integrates with VS Code, JetBrains IDEs, and other editors as an extension.

1. Feature Implementation

Building new features involves creating models, writing business logic, building API endpoints, and connecting frontend components. Claude Code handles the full vertical slice.

"Add a user notification system to our application. Users should receive notifications when: someone comments on their post, their account settings are changed, or they receive a direct message. Create a notifications model with fields for recipient, type, message, read status, and timestamp. Build API endpoints for: fetching all notifications for the current user, marking a notification as read, marking all as read, and deleting a notification. Add a simple frontend component that shows the unread notification count in the nav bar and displays a dropdown list when clicked. Follow the existing patterns in the codebase for models, serializers, and views. Include appropriate error handling and input validation. Run the tests after implementation to make sure nothing is broken."

Claude Code reads your existing models, views, and frontend patterns before writing anything. The result follows your project's conventions rather than imposing generic patterns. It will also run your test suite and fix any failures it introduced.

2. Bug Investigation and Fix

Debugging often involves tedious tracing through multiple files to find where things break. Claude Code can systematically investigate, identify root causes, and implement fixes.

"Users are reporting that the search function returns no results when they include special characters like '&' or '#' in their query. Investigate the issue by tracing through the search implementation from the frontend input handler through the API endpoint to the database query. Identify exactly where the problem occurs, explain what is causing it, and implement a fix. Make sure the fix handles all common special characters, not just the ones reported. Add test cases that verify the correct behavior for: normal queries, queries with special characters, empty queries, and very long queries. Run the full test suite to confirm nothing else breaks."

The AI agent traces through your codebase the way a senior developer would, reading the code path from input to output, identifying the vulnerability, and implementing a comprehensive fix rather than just patching the reported symptom.

3. Code Refactoring

Refactoring requires deep understanding of existing code before making changes. Claude Code can analyze the current state, identify problems, and implement cleaner patterns while maintaining functionality.

"Our user authentication module has grown organically over the past year and has become difficult to maintain. The main issues are: business logic mixed with request handling in the views, duplicated validation logic between the registration and profile update flows, and inconsistent error response formats. Refactor this module to: separate business logic into a service layer, create a shared validation module used by both flows, standardize error responses using our existing error handling patterns, and remove any dead code you find. After refactoring, ensure the entire test suite passes. If any tests need to be updated to reflect the new structure, update them. Create a summary of all changes made and the reasoning behind each decision."

The summary at the end is valuable for code review. It documents not just what changed but why, making it easier for your team to understand and approve the refactoring.

4. Test Coverage Improvement

Writing comprehensive tests is essential but time-consuming, especially for modules with complex business logic or many edge cases.

"Our payment processing module in 'src/payments/' has low test coverage. Review the existing code and add comprehensive tests covering: successful payment flows for all supported payment methods (credit card, ACH, and wire transfer), failure scenarios (declined card, insufficient funds, network timeout, invalid payment details), edge cases (zero amount, negative amount, amount exceeding maximum, currency conversion), webhook handling for payment status updates from our payment provider, and the retry logic for failed transactions. Use our existing test patterns and the pytest framework. Mock external API calls using our existing mock fixtures in 'tests/fixtures/'. Aim for at least 85% code coverage on the payments module. Document any areas that are genuinely difficult to test and explain why."

Claude Code reads your existing test patterns and fixtures to ensure the new tests are consistent with your codebase style. The documentation of hard-to-test areas is useful for technical debt tracking.

5. API Documentation Generation

API documentation requires attention to detail, consistency, and regular updates as endpoints change. Generating it from the actual code ensures accuracy.

"Our REST API has grown to over 40 endpoints but the documentation has not kept pace. Review all API endpoints in our codebase and generate comprehensive documentation. For each endpoint, include: the HTTP method and URL path, a description of what it does, authentication requirements, request parameters (query params, path params, and request body) with types and whether they are required, response format with example JSON for both success and error cases, any rate limiting that applies, and relevant notes about pagination or filtering. Organize the documentation by resource (users, projects, billing, etc.). Format this as Markdown that we can publish to our developer portal. Flag any endpoints where the behavior is unclear from the code or where the error handling seems incomplete."

Documentation generated from actual code is more accurate than manually maintained docs. The flagging of unclear behavior is a bonus, it surfaces potential issues that might otherwise go unnoticed.

6. Database Schema and Migrations

Database changes need to be done carefully, especially on production systems. Claude Code can design schemas, create migrations, and handle the associated model and query updates.

"We need to add multi-tenancy support to our application. Design and implement the database changes needed to support multiple organizations, where each user belongs to one organization and all data (projects, documents, billing) is scoped to an organization. Create the Organization model with fields for: name, slug, subscription tier, creation date, and settings (as a JSON field). Add an organization foreign key to the User, Project, Document, and Invoice models. Create the database migration. Update all existing queries to filter by organization. Add middleware that determines the current organization from the request (either from a subdomain or from the authenticated user's organization). Make sure existing tests are updated and passing. Do not delete any existing data, ensure the migration handles existing records by assigning them to a default organization."

This is a complex, multi-file change that touches models, queries, middleware, and tests. Claude Code handles the coordination across all these files while respecting the critical constraint of not losing existing data.

7. Dependency Updates and Breaking Changes

Upgrading major dependencies is one of the most dreaded tasks in software development. It touches every file, breaks things in unpredictable ways, and gets postponed for months because of the effort involved. Claude Code can handle the entire migration systematically.

"We need to upgrade our project from Django 4.2 to Django 5.1. First, review the Django 5.0 and 5.1 release notes and identify every deprecation and breaking change that affects our codebase. Then scan our entire project for any code that uses deprecated or removed features. Create a summary of all changes needed before starting. Once you have the full picture, update the dependency in our requirements file, then go through each affected file and update the code to use the new patterns. Pay special attention to: any changes in URL routing syntax, deprecated model field options, updated middleware handling, and removed utility functions. After making all changes, run the full test suite. Fix any failures that result from the upgrade. Create a migration summary document listing every file changed and what was updated, so the team can review the changes efficiently."

This is one of the highest-value workflows for Claude Code because it combines research (reading release notes), analysis (scanning for affected code), and implementation (updating everything) into a single session. Tasks that developers delay for months get done in minutes.

8. Performance Optimization

Performance issues often require profiling, analysis, and targeted optimization. Claude Code can investigate slow areas and implement improvements.

"Our project listing page is loading slowly, taking over 3 seconds on average. Investigate the performance issue. Start by examining the view that handles the project list endpoint. Check for: N+1 query problems (missing select_related or prefetch_related calls), unnecessary database queries that could be eliminated or combined, large querysets being loaded without pagination, serializer fields that trigger additional queries, and any synchronous operations that could be made asynchronous. Implement optimizations for every issue you find. Add database query logging to measure the before and after. Run the existing tests to make sure the optimizations do not change the API behavior. Create a summary showing: what you found, what you changed, and the expected impact on query count and response time."

The before-and-after measurement makes the optimization results concrete and gives you data to include in performance reviews or sprint retrospectives.

9. Security Audit and Fixes

Security vulnerabilities can hide in plain sight. Claude Code can systematically review your codebase for common security issues and fix them.

"Conduct a security audit of our web application. Check for the following vulnerabilities: SQL injection (any raw queries or string interpolation in database calls), cross-site scripting (XSS) in any user-generated content rendering, cross-site request forgery (CSRF) protection on all state-changing endpoints, authentication bypass (endpoints that should require auth but do not), insecure direct object references (users accessing resources that belong to others), sensitive data exposure (passwords, API keys, or tokens in logs, error messages, or responses), missing rate limiting on authentication endpoints, and insecure file upload handling. For each issue you find, document: the file and line number, the severity (critical, high, medium, low), a description of the vulnerability and how it could be exploited, and your recommended fix. Then implement the fixes for all critical and high severity issues. Run the test suite after making changes. Create a security audit report document with all findings."

This is one of the most valuable development workflows because security vulnerabilities are easy to miss in manual code review and can have severe consequences. The structured severity ratings help prioritize remediation.

10. CI/CD Pipeline Configuration

Setting up or improving CI/CD pipelines involves configuration files, environment variables, deployment scripts, and integration with various services. Claude Code can handle the full setup.

"Set up a GitHub Actions CI/CD pipeline for our project. The pipeline should: run on every push to main and on every pull request. For the CI stage: install dependencies, run linting (we use ESLint and Prettier), run the full test suite with coverage reporting, and fail the build if coverage drops below 80%. For the CD stage (only on pushes to main): build the Docker image, push it to our container registry at ghcr.io, and deploy to our staging environment using the existing Kubernetes manifests in the 'k8s/' folder. Add a separate workflow for production deployments that triggers on GitHub releases and requires manual approval. Include caching for dependencies to speed up builds. Create the necessary GitHub Actions workflow files, update the Dockerfile if needed, and document any secrets or environment variables that need to be configured in the GitHub repository settings."

CI/CD configuration is often done once and then becomes difficult to maintain because the person who set it up has moved on. Claude Code creates well-documented, maintainable pipeline configurations.

Tips for Working with Claude Code

Let it explore first. When you start a session, Claude Code reads your project structure automatically. For complex tasks, let it explore the relevant parts of your codebase before making changes. It produces better results when it understands the full context.

Always run the tests. Include "run the test suite" in your prompts. Claude Code will execute your tests and fix any failures it introduced, which catches issues before they reach code review.

Use it for the tedious parts. Claude Code is most valuable for tasks that are straightforward but time-consuming: writing tests, generating documentation, implementing boilerplate, and doing repetitive refactoring. You focus on architecture and design decisions.

Review the output. This AI agent is powerful, but it is not infallible. Always review the code it produces, especially for security-sensitive changes, performance-critical paths, and business logic. Think of it as a very capable junior developer whose work you should still code-review.

Reference existing code. Telling Claude Code to "follow the patterns in our existing user endpoints" produces much better results than letting it use its own conventions. It reads your code and matches the style.

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