How to Use AI to Document Code, APIs, and READMEs in 2026

## Quick Answer

Use AI to generate JSDoc/TSDoc inline, OpenAPI specs from your routes, and READMEs from your `package.json` plus directory tree. Cursor and Claude Code are best for repo-scale docs; Copilot is best for inline comments.

- TSDoc generation is near-perfect for typed code - Never publish AI-generated docs without reading them once - Auto-regenerate docs on CI to prevent drift

## What You'll Need

- TypeScript/JavaScript project (docs workflows adapt to Python, Go, Rust) - An AI IDE or CLI - `typedoc` or `jsdoc` for generated output - Optional: Fumadocs, Mintlify, or Docusaurus for publishing

## Steps

1. **Generate JSDoc for a function.** In Copilot: type `/**` above a function and press Tab. In Cursor: `Add TSDoc to all exports in this file.` 2. **Include examples.** Prompt: `Add an @example block showing typical usage.` 3. **Generate README from scratch.** Attach `package.json`, top-level folders, and prompt: `Write a README with install, usage, API, and contributing sections.` 4. **Generate OpenAPI from Express/Fastify routes.** Prompt: `Read these route handlers and produce an OpenAPI 3.1 spec.` 5. **Run doc CI.** Add `typedoc --out docs` to your build step. 6. **Publish with Fumadocs.** Self-hosted, free, MDX-powered. 7. **Keep docs fresh.** Run `scripts/update-docs.ts` via Husky pre-push: if source changed without doc changes, fail.

## Common Mistakes

- **Letting AI invent function behavior.** Always verify `@returns` and `@throws` match the code. - **Generic examples.** AI loves `foo/bar/baz`. Ask for real examples from your domain. - **Outdated code blocks.** Snippets in docs rot fast — test them in CI. - **No ownership.** Someone on the team must own docs or they die.

## Top Tools

| Tool | Best For | |------|----------| | Mintlify Writer | Inline JSDoc/TSDoc | | GitHub Copilot | Comment autocompletion | | Cursor | Repo-wide README generation | | TypeDoc | Publishing TS API reference | | Fumadocs | Self-hosted docs site |

## FAQs

**Can AI write an accurate API reference?** Yes, if types are strict. Loose TypeScript produces weaker docs.

**Will AI document private functions?** Only if you ask. Default is exports only — which is correct.

**Does AI generate diagrams?** Mermaid diagrams yes, via prompts like: `Create a Mermaid flowchart for this data flow.`

**Can I publish AI docs on GitHub Pages?** Yes. TypeDoc emits static HTML that deploys to any static host.

**How do I prevent docs from drifting?** CI check: if source modified, doc file timestamp must also change.

**What about multi-language projects?** AI handles Python docstrings, Go comments, and Rust doc comments equally well.

## Conclusion

Docs are the cheapest quality multiplier in software. With AI, the excuse "I don't have time to document" is gone. Set up TypeDoc + Copilot today; publish with Fumadocs. [Misar Blog](https://misar.blog) has templates for API docs in five frameworks.