PostMD MCP Server

stdio Model Context Protocol server for PostMD — publish a Markdown document, get a web page you share by link. Optional groups, document passwords, share expiry and viewer themes. This server wraps PostMD's public API (/api/v1) so assistants can publish, read, update and organize documents.

Publishing needs no account and no key. With zero configuration this server can already turn Markdown into a shareable page. An API key adds management: updating and deleting your documents, attachments, and groups.

Anonymous documents come with a control token. Publishing without a key returns data.controlToken and data.retainedUntil: the document is deleted at that instant, and the token is the only way to update or delete it before then. It is shown once and cannot be reissued, so keep it with the docCode. Pass it as controlToken to the update and delete tools and they work without an API key.

HTTP reference: postmd.turink.com/docs/api · machine-readable spec at /api-docs

Requirements

• Node.js 20 or later
• Nothing else. An API key (pmk_…) only for the management tools.

Configuration

All variables are optional.

Load order: this repo's .env (if present) is applied via dotenv without overwriting variables already set by the host (e.g. MCP env). Do not commit .env or keys.

Tools

Publishing and reading — no key needed:

Managing documents — key with documents:write:

Each of the first three also accepts controlToken instead of a key, for a document published anonymously.

Replacing content on a document that has notes

Notes are located by the text they quote, not by a stored position. Replacing a document's body therefore moves or loses where they point: a note whose quote is gone loses its place in the body, and one whose quote now appears elsewhere points there instead. The note itself, including the quoted text, is kept either way.

Both update tools require notesOnReplace whenever new content is sent.

Metadata-only updates do not take it.

Notes and highlights — key with documents:read / documents:write. A note is text anchored to a quoted passage; a highlight is the same object carrying only a colour. Visibility comes from ownership: on the key member's own document a note is PRIVATE or SHARED, and on anyone else's document it is always SHARED. Documents nobody owns — anonymous uploads and service-owned pages — take no notes:

Groups — key with groups:read / groups:write:

For uploads: either pass the full Markdown as the markdown argument, or pass a local filePath only so this server reads the file. The path must exist on the machine running the MCP server.

Quickstart

Nothing to install. npx fetches the package and the MCP client spawns it.

npx -y postmd-mcp-server

Run it by hand only to check that it starts — it speaks MCP over stdin and stdout, so it will sit there waiting for a client.

Client configuration

Claude Code:

claude mcp add postmd -- npx -y postmd-mcp-server

Cursor (~/.cursor/mcp.json) and most other stdio clients:

{
  "mcpServers": {
    "PostMD": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "postmd-mcp-server"],
      "env": { "POSTMD_API_KEY": "pmk_…" }
    }
  }
}

To run a checkout instead — changing the code, or debugging against a local PostMD — point the client at the file.

git clone https://github.com/reinlainer/postmd-mcp-server.git
cd postmd-mcp-server && npm ci
claude mcp add postmd-dev -- node "$PWD/src/index.js"

Leave env out entirely for publish/read-only use. cp .env.example .env works too — the server loads its own .env.

Smoke test

Runs the full write path against a live server and cleans up after itself. Needs a key with all four scopes.

export POSTMD_API_KEY=pmk_…
npm run smoke

Creates a group and a passworded document, reads it back, updates it, clears the password, then deletes both. It also publishes one document with no credential and removes it with the control token.

Stack

@modelcontextprotocol/sdk 1.30.0, dotenv. License: MIT.