Postmd MCP Server

PostMD MCP Server

Model Context Protocol server for PostMD — publish a Markdown document, get a web page you share by link, and add a document graph that the viewer draws: the reading order, the bodies and rules a document names, a procedure spread over its chapters. Optional groups, document passwords 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, and the hosted server at https://postmd.turink.com/mcp needs no install either. An API key adds management: organizing documents in groups, and notes.

30-day retention. Documents have a 30-day retention period (data.retainedUntil) that extends by 30 days whenever the document is read (at most once per day). Documents without a password can be updated or deleted by anyone; password-protected documents require the password or the owner's API key.

Where things are written down: /llms.txt lists what the service can do and which page answers each thing; it is the place to start. /docs/api is the HTTP reference and /api-docs the machine-readable spec.

Hosted or local

The hosted server has no way to receive an API key, so it carries only the tools that need none. Groups, notes and the tools that read a file from your disk are local-only.

Configuration

Local only — the hosted server reads none of these. All 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

Every tool below works on the local server. The hosted server carries five of them: postmd_create_document, postmd_get_document, postmd_get_document_raw, postmd_update_document, and postmd_delete_document.

Publishing and reading — no key needed:

Managing documents — key with documents:write (or password / no credential for unowned documents without password):

Graphs

A PostMD document can carry graph data that the viewer draws, showing how the parts of the document relate. No tool here creates or edits a graph, because there is no endpoint for one: the data sits in the Markdown as an HTML comment and travels with the body.

Adding a graph to an existing document therefore means reading it with postmd_get_document_raw, inserting the comment, and sending the whole body back with postmd_update_document. Publishing a new document with a graph is an ordinary postmd_create_document call.

The format is at https://postmd.turink.com/docs/graph. Working out what the nodes are and how they connect requires reading the document, which is the calling agent's part; PostMD only draws what it finds.

Keeping the code in the file

A Markdown file can carry the code of the document it was published as, in an HTML comment at its top marked postmd:document. A later session that opens the file can then tell which document to update without being given the address. The format is at https://postmd.turink.com/docs/api, "Keeping the code in the file". No tool here writes the comment; the calling agent edits its own file.

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.

Client configuration

Hosted

Claude Code:

claude mcp add --transport http postmd https://postmd.turink.com/mcp

Clients that take a JSON config:

{
  "mcpServers": {
    "PostMD": {
      "type": "http",
      "url": "https://postmd.turink.com/mcp"
    }
  }
}

In ChatGPT, add it under Settings → Apps; in claude.ai, under Settings → Connectors. There is nothing to authorize.

Local

There is nothing to install: npx fetches the package and the client spawns it.

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.

Running npx -y postmd-mcp-server by hand only checks that it starts. It speaks MCP over stdin and stdout, so it will sit there waiting for a client.

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 without a token.

Stack

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