If you're building with AI agents — Claude Code, Cursor, Windsurf, ChatGPT plugins, or custom bots — you've probably hit the same wall: your agents forget everything between sessions. This comparison covers every serious option for storing and sharing .md files across your AI agents and chatbots, so you can pick the right one.
Every AI coding session starts cold. Your agent doesn't remember the architecture decisions you made last week, the team conventions it learned, or the tasks it left half-finished. The standard fix is to store that context as plain markdown files that the agent reads at the start of each session — a pattern popularised by CLAUDE.md, AGENTS.md, and similar files.
The problem: where do you actually store those files so every agent, on every machine, can read and write them? Local files only work on one device. Git repos add friction. You need a service that connects directly to your AI tools.
| Feature | ReadmeDB | HackMD | GitHub | Obsidian |
|---|---|---|---|---|
| Native MCP support | Yes — built-in | No | No | No |
| AI agent can read files | Yes — direct API | Via REST API | Via API / clone | Local only |
| AI agent can write files | Yes — direct API | Via REST API | Via API + commit | Local only |
| Setup time | 30 seconds | Minutes–hours | Minutes–hours | Minutes + sync config |
| Works with cloud agents | Yes | With custom code | With custom code | No (local only) |
| Full-text search for agents | Yes — 1 tool call | No agent API | No agent API | No |
| Automatic versioning | Yes — 10 snapshots | Manual history | Yes — git log | Via git plugin |
| Free tier | 50 files, 5 MB | Free (limited) | Unlimited public repos | Free (local) |
| Conflict-free concurrent writes | Yes — DB transactions | Partial (CRDT collab) | No — merge conflicts | No |
| Works with Claude Code | Yes — 1 config line | No native support | No native support | No native support |
| Works with Cursor | Yes — 1 config line | No native support | No native support | No native support |
ReadmeDB is built specifically for AI agents. It is a hosted MCP (Model Context Protocol) server that gives your agents a persistent markdown file store via a standard protocol that Claude Code, Cursor, Windsurf, Codex CLI, and any MCP-compatible host understand natively. You add one JSON config block, restart your editor, and your agent has a permanent filesystem.
Agents get 16 tools: read, write, search, patch, append, version history, diffs, bulk reads, and more. Files are stored in Postgres, versioned automatically, and searchable with full-text queries — all reachable with one API call, no custom integration needed.
HackMD is a collaborative markdown editor with a REST API and Git integration. It works well for human teams sharing notes, and its Accept: text/markdown header lets web-browsing agents read raw markdown. However, HackMD has no native MCP server, so connecting it to Claude Code, Cursor, or Windsurf requires writing custom integration code. Agents cannot write files back to HackMD without additional middleware.
Best for: Human teams collaborating on markdown documents. Not purpose-built for AI agent workflows.
A Git repository is the most robust option if you are running autonomous agents with a human review step. Agents like Devin or custom scripts can clone, commit, and open pull requests. The trade-off is friction: every write requires a commit, every read may require a clone, and agents in cloud environments need a Personal Access Token scoped to specific repos.
GitHub has no native MCP server either, so connecting it to Claude Code or Cursor requires custom tooling or a third-party MCP adapter. Search across your markdown files from within an agent session is not a native capability.
Best for: Autonomous agents that submit changes for human review via pull requests. Too heavyweight for a shared in-session memory store.
Obsidian is a local-first markdown knowledge base. Your files live in a folder (called a vault) on your machine, and local agents like Claude Code or custom Python scripts can read and write them directly. Sync across machines requires either Obsidian Sync (paid) or a Git-based workflow.
The fundamental limitation for AI agent workflows: Obsidian files are local, so cloud-hosted agents cannot reach them without a separate sync layer. There is no API endpoint and no MCP server built in, so sharing context across multiple agents or machines adds significant setup complexity.
Best for: A personal "second brain" on a single machine with local agents only.
You want Claude Code, Cursor, and Windsurf to all read the same memory files. You want cloud agents to access context. You want setup to take 30 seconds, not 30 minutes.
Your agents propose changes via pull requests, and a human reviews before merging. You already have a git workflow and want agents integrated into it.
Your primary use case is a team writing markdown together, and agents are secondary. HackMD's real-time collaboration features are best in class for this.
You work on one machine, you want full control over your files locally, and you don't need cloud agents or cross-platform access.
ReadmeDB implements the Model Context Protocol (MCP), the open standard from Anthropic for connecting AI agents to external tools. Every MCP-compatible host — Claude Code, Cursor, Windsurf, Codex CLI, Claude Desktop — can connect with one config block:
{
"mcpServers": {
"readmedb": {
"url": "https://app.readmedb.com/api/mcp",
"headers": { "Authorization": "Bearer rdb_your_key" }
}
}
}Sign up for free, generate a key, paste the config, restart your editor. Your agent can now read, write, search, and version .md files — persistently, across every session and every platform.