Markdown file types

Common .md files for AI and software projects

Modern projects use Markdown files for humans, AI coding agents, documentation systems, changelogs, prompts, and design decisions.

Jun 13, 2026 · 9 min read

The most useful .md files

File	Purpose
README.md	Project overview, setup, usage, and first context layer.
AGENTS.md	Instructions for AI coding agents.
CLAUDE.md	Claude Code project memory and workflow rules.
DESIGN.md	Design intent, architecture decisions, and trade-offs.
CHANGELOG.md	Release notes and version history.
TODO.md	Task list, backlog, or implementation checklist.
PROMPTS.md	Reusable AI prompts and prompt patterns.
API.md	API endpoints, examples, payloads, and auth notes.
CONTRIBUTING.md	Contribution rules, branch workflow, and review expectations.

How these files work together

Use README.md as the front door. Use AGENTS.md and CLAUDE.md to guide AI tools. Use DESIGN.md to explain intent before code changes. Use CHANGELOG.md and TODO.md to keep project state visible. Use PROMPTS.md when your team repeatedly asks AI tools to perform similar work.

Why file names matter for AI

Predictable names help humans and agents find the right context quickly. A coding agent can infer that README.md is a project overview, AGENTS.md is an instruction file, and DESIGN.md contains decisions. Clear names reduce ambiguity and improve retrieval.

Recommended folder pattern

project/
  README.md
  AGENTS.md
  CLAUDE.md
  DESIGN.md
  CHANGELOG.md
  TODO.md
  docs/
    API.md
    PROMPTS.md
    ARCHITECTURE.md

Edit and preview your .md files

Use Markdown Docs online editor for quick previews or download Markdown Docs to open and edit local `.md` files on Windows.

Related references

GitHub README docs for README.md behavior.
OpenAI Codex AGENTS.md guide for AGENTS.md.
Anthropic Claude Code memory docs for CLAUDE.md.

FAQ

Do all projects need every .md file?

No. Start with README.md. Add AGENTS.md, CLAUDE.md, DESIGN.md, or PROMPTS.md only when the project needs that type of context.

Are Markdown file names case-sensitive?

On some systems, file names can be case-sensitive. Use conventional uppercase names like README.md, AGENTS.md, and CLAUDE.md for clarity.

Can Markdown Docs edit all these files?

Yes. Markdown Docs can open, edit, preview, and save Markdown files such as README.md, AGENTS.md, CLAUDE.md, DESIGN.md, TODO.md, and CHANGELOG.md.