How to Generate Documentation from Code Using AI (2025 Guide)

Documentation is the least favorite task for most developers. It's tedious, time-consuming, and often outdated the moment you finish writing it.

But in 2025, AI has fundamentally changed how we approach documentation. You can now generate comprehensive, accurate documentation for an entire codebase in minutes, not days.

This guide covers every practical method to generate documentation from code using AI, from dedicated documentation platforms to prompts you can use with any AI assistant.

Why AI-Generated Documentation Works

Before diving into tools, let's address the skepticism: Can AI really write good documentation?

The answer is yes, with caveats. AI excels at:

• Describing what code does: Function signatures, parameters, return types
• Explaining logic flow: How different parts connect and interact
• Generating consistent formatting: JSDoc, docstrings, markdown
• Creating boilerplate docs: README files, API references, setup guides

AI struggles with:

• Business context: Why certain decisions were made
• Edge cases: Subtle behaviors that aren't obvious from code
• Institutional knowledge: Historical context, deprecated approaches

The best approach: use AI to generate the 80% of documentation that's mechanical, then spend your time on the 20% that requires human context.

Method 1: Dedicated Documentation Platforms

If documentation is a serious need for your team, dedicated platforms offer the most polished experience.

Mintlify

Mintlify is used by companies like Anthropic, Cursor, and Perplexity for their public documentation. It's an AI-powered documentation platform that creates beautiful, searchable docs.

Key features:

• AI writing assistant: Generate and improve documentation with AI suggestions
• Git-based workflow: Docs live in your repo, update with your code
• API reference generation: Automatically generate docs from OpenAPI specs
• Beautiful templates: Professional design out of the box
• Search powered by AI: Users can ask questions, not just search keywords

Best for: Teams building public-facing documentation, API references, and developer portals.

How to use:

1. Connect your GitHub repository to Mintlify
2. Add a docs/ folder with markdown files
3. Use Mintlify's AI to generate initial content from your codebase
4. Customize and refine with their visual editor
5. Deploy (docs auto-update when you push to Git)

DocuWriter.ai

DocuWriter.ai focuses specifically on generating code documentation and API docs from source files.

Key features:

• Code documentation generation: Analyzes source files and generates inline docs
• API documentation: Creates comprehensive API references
• Multiple languages: Supports JavaScript, Python, Java, Go, and more
• GitHub integration: Import repositories directly
• Export options: Markdown, HTML, or integrate with your existing docs

Best for: Generating technical documentation quickly, especially inline code comments and API references.

Workflow with OneFile:

Before generating documentation with DocuWriter.ai, you can use OneFile to prepare your codebase:

1. Go to onefileapp.com and upload your project folder (or import from GitHub)
2. Download the combined file
3. Upload to DocuWriter.ai for analysis
4. Review generated documentation and export

Alternatively, DocuWriter.ai supports direct GitHub import.

Method 2: AI Coding Assistants

If you already use an AI coding assistant, you have powerful documentation capabilities built in. These tools understand your codebase context and can generate docs inline as you work.

Cursor

Cursor is an AI-first code editor built on VS Code. It can generate documentation across your entire project.

Generate inline documentation:

1. Select a function or a code block
2. Press Cmd+K (Mac) or Ctrl+K (Windows)
3. Type: "Add JSDoc comments to all functions"

Generate a README:

1. Open the AI pane with Cmd+I
2. Use this prompt:

Windsurf

Windsurf (by Codeium) is another AI-powered IDE with strong documentation capabilities through its Cascade feature.

Best documentation prompt for Windsurf:

Claude Code (CLI)

Claude Code is Anthropic's command-line tool that brings Claude directly into your terminal with full codebase awareness.

Why it's great for documentation:

• Automatically indexes your entire codebase
• Understands file relationships and dependencies
• Can create and edit multiple files at once
• Works from your terminal with no practical context window limits

Documentation prompts for Claude Code:

Generate a complete README:

Add documentation to existing code:

Generate API documentation:

Method 3: General-Purpose AI (ChatGPT, Claude, Gemini)

Don't have access to specialized tools? Any modern AI assistant can generate documentation. You just need to give it your code.

The Challenge: Context

The main limitation of ChatGPT, Claude, and Gemini for documentation is context. They can only see what you paste or upload. For a single file, that's easy. For an entire codebase? You need a strategy.

Solution: Combine Your Codebase First

The most effective approach is to combine your entire codebase into a single file before uploading. This gives the AI complete context to understand how everything connects.

Using OneFile:

1. Go to onefileapp.com
2. Drag your project folder (or import from GitHub)
3. OneFile automatically skips node_modules, .git, build artifacts
4. Download the combined file
5. Upload to ChatGPT, Claude, or Gemini

Best Documentation Prompts

Once your codebase is uploaded, use these prompts:

Comprehensive README:

API Documentation:

Inline Code Comments:

Architecture Overview:

Model Comparison for Documentation

Best Practices for AI-Generated Documentation

1. Always Review and Edit

AI-generated documentation is a starting point, not a finished product. Always review for:

• Accuracy (AI can misunderstand intent)
• Completeness (important details might be missing)
• Tone (ensure it matches your team's style)
• Security (remove any sensitive information that slipped through)

2. Provide Context in Your Prompts

The more context you give, the better the output. Include:

• Who the documentation is for (beginners, experienced devs, end users)
• What format you need (markdown, JSDoc, reStructuredText)
• Any existing conventions in your project
• Specific areas that need more detail

3. Document Incrementally

Don't try to document everything at once. Start with:

1. README: Project overview and quick start
2. API reference: Public interfaces and functions
3. Architecture: How the system works
4. Contributing guide: How to add new code

4. Keep Documentation in Sync

Documentation that's out of date is worse than no documentation. Use tools that integrate with your Git workflow (like Mintlify) or regenerate docs periodically with AI.

Quick Reference: Which Method to Use

Conclusion

Documentation no longer has to be the task you dread. With AI tools available in 2025, you can generate comprehensive docs in minutes instead of days.

The key is choosing the right tool for your needs:

• Mintlify for polished, public-facing documentation
• DocuWriter.ai for quick code and API documentation
• Cursor, Windsurf, or Claude Code for inline docs as you code
• ChatGPT, Claude, or Gemini (with OneFile) for flexible, one-time documentation tasks

Start with a README. It takes five minutes with AI and makes your project immediately more accessible to others, and to future you.