OpenMarkdown

OpenMarkdown is a local-first Markdown editor built for speed and agent-native collaboration. It opens in under a second, stores everything as plain .md files on your disk, and works with any MCP-compatible AI agent — Claude, ChatGPT Codex, Gemini CLI, GitHub Copilot, Cursor, and more. There's no database, no cloud sync, and no account required. You own your files, and they stay yours.

The editor is written in Rust, which makes it incredibly fast. Cold starts take less than a second, and the window appears before you let go of the mouse. But the real innovation is how it integrates with AI agents. You can ask your agent to open a file, and it will scroll to the right heading. You can select a messy list, ask the agent to reformat it into a table, and it edits the file in place — no copy-paste through a chat box. The agent reads exactly what you selected and rewrites it directly. Your file remains a plain .md file on your disk, unchanged in format.

OpenMarkdown is ideal for developers, writers, and anyone who takes notes or manages knowledge bases. If you already use an AI coding assistant or chatbot, this editor lets you bring that agent into your writing workflow without locking your data into a proprietary system. It's also great for teams that want to keep their notes in version control or sync them with any file-syncing service. The tool is free, open-source, and runs on macOS (with more platforms likely coming). If you value speed, simplicity, and owning your data, OpenMarkdown is worth a look.