40+ ChatGPT Prompts to Automate Code Documentation

Introduction: Why Documentation Still Matters in 2025

In the fast-paced world of software development, code gets written, rewritten, refactored—and often forgotten. But if you ask any seasoned American developer or engineering manager, they’ll tell you the same thing:

Code is temporary. Good documentation is forever.

Whether you’re a freelance developer in Texas, a Silicon Valley software engineer, or a bootcamp graduate in New Jersey, documenting your code clearly isn’t just good practice it’s a career asset.

With ChatGPT, documenting your code can be faster, clearer, and more consistent. The trick? You need to ask the right prompts.

40 Detailed ChatGPT Prompts for Code Documentation

🔧 Function and Method Docstrings

1. "Write a Python docstring for this function that calculates total sales tax and handles input validation, exceptions, and edge cases."

2. "Document this Java method using Javadoc, including parameter types, return values, and any exceptions thrown."

3. "Generate a concise docstring for this Python function that takes a list and returns a reversed copy."

4. "Add a detailed docstring to this C++ function that converts Fahrenheit to Celsius and handles invalid temperature input."

5. "Write a JavaScript function comment block explaining the purpose, input format, expected output, and assumptions made."

📄 Module and File-Level Documentation

6. "Create a module-level docstring for a Python file that defines multiple utility functions for string manipulation."

7. "Write a documentation header for this JavaScript file used in user authentication, covering imports, functions, and context."

8. "Document this C# class file with a summary of its purpose, public methods, and expected usage in a .NET application."

9. "Generate a comment block describing the role of this TypeScript file in handling API communication for a React frontend."

10. "Explain the high-level logic of this Ruby script, including external dependencies and how to execute it from terminal."

🧱 Class and Object-Oriented Documentation

11. "Write Python class-level documentation describing attributes, constructor behavior, and public methods with expected inputs and outputs."

12. "Generate documentation for a Java class implementing an interface with overridden methods and private member variables."

13. "Add descriptive comments for this JavaScript ES6 class with a constructor and two async methods handling network requests."

14. "Create a header for a C++ class that defines a matrix object, detailing its constructors, member functions, and operators."

15. "Write a complete class comment block for a Django model including field definitions, relationships, and meta attributes."

🔍 Inline Comments and Logic Explanations

16. "Add line-by-line inline comments explaining what each step does in this Python data processing function."

17. "Explain this SQL query logic using inline comments, particularly focusing on joins, filters, and grouping operations."

18. "Insert inline comments in this JavaScript code to clarify DOM manipulation and event handling flow."

19. "Comment each conditional block in this C++ loop to indicate its role in sorting an integer array."

20. "Document each step in this React component’s useEffect hook to explain dependencies and cleanup behavior."

📘 README and Usage Instructions

21. "Write a README section explaining how to install, run, and configure this Node.js backend app with environment variables."

22. "Generate a README snippet showing Python virtual environment setup and execution steps for this script."

23. "Write a usage guide for this command-line tool written in Go, including example flags and output formats."

24. "Document the prerequisites, installation steps, and run commands for this full-stack MERN project."

25. "Create a clear Getting Started section for this Django REST API project in a USA developer-friendly tone."

📡 API Endpoint Documentation

26. "Document this Express.js route using OpenAPI/Swagger syntax, including parameters, request body, and response types."

27. "Write an explanation of a RESTful GET endpoint in Flask that retrieves user profiles by ID."

28. "Create a detailed description for this FastAPI POST endpoint, including payload format and validation rules."

29. "Write API documentation for a PUT route that updates a product, including possible HTTP status codes."

30. "Generate Swagger annotations for this Spring Boot controller method that deletes a record by primary key."

🧪 Tests and Documentation for Testing Suites

31. "Write inline comments for this unit test in Python explaining each assertion and mock behavior."

32. "Document this Java JUnit test case with setup description and test purpose summary."

33. "Create a summary docstring for this Jest test suite covering API response validation."

34. "Generate test file documentation for this integration test using Cypress in a React project."

35. "Write comments in this PyTest function explaining the use of fixtures and expected outcomes."

🧭 Versioning and Changelog Notes

36. "Write a changelog entry for version 2.0 that includes performance improvements and new feature additions."

37. "Generate a comment summarizing the difference between this version and the last commit in Git."

38. "Document this function refactor, explaining deprecated arguments and updated return behavior."

39. "Write a migration comment block for changes in database schema involving two renamed columns."

40. "Create a note for API consumers about updated response formats in v1.1 of the product endpoint."

Best Practices for Using ChatGPT to Write Documentation

• Always provide context: Include function names, file purpose, and expected usage in your prompt.
• Request format-specific outputs: Ask for Markdown, reStructuredText, Swagger YAML, or Javadoc depending on your stack.
• Refine with follow-ups: You can follow up with “Make it shorter,” “Add a usage example,” or “Focus on return values.”
• Use version-awareness: If your app targets U.S. developers, clarify framework versions and platform dependencies.
• Tailor to your audience: Whether you're writing for junior devs, data scientists, or external API users, prompt accordingly.

FAQs – Documenting Code with ChatGPT in the U.S.

Q1: Is ChatGPT accurate when writing technical documentation?
Yes, when given full context. Always review and test its output to ensure correctness and clarity, especially for public APIs.

Q2: Can I use ChatGPT to write README files for open-source U.S. projects?
Absolutely. You can prompt it to format for GitHub markdown, include badges, and structure it with standard U.S. open-source conventions.

Q3: What’s the best way to prompt ChatGPT for documentation?
Use detailed instructions like: “Write a Python docstring for this function, explain parameters, and list exceptions.”

Q4: Is ChatGPT useful for documenting legacy code?
Yes. Paste in the code and ask it to infer purpose, describe logic, or write summaries for outdated functions.

Q5: Can ChatGPT generate documentation that meets enterprise/U.S. compliance standards?
It can draft content aligned with your guidelines, but a human reviewer should finalize anything for HIPAA, SOX, or legal compliance.

Final Thoughts: Make Documentation a Strength, Not an Afterthought

Code speaks but documentation explains.

In a professional U.S. software environment where teamwork, onboarding, and long-term code health matter, clean documentation is a sign of thoughtful engineering.

With these 40+ expert-level ChatGPT prompts, you’ll write code that’s not only functional but also beautifully understood.

Ready to make your documentation as strong as your code?

Start using these ChatGPT prompts today and turn every function, class, and project into a learning tool for your future self and your team.