Rapier

npx add-mcp 'https://mcp.rapier.website/door/mcp'

Rapier - Markdown Editor & Art: plugins and packages

Plugins, npm packages and plug-in files for Rapier - Markdown Editor & Art. Markdown editor for writing, notes, editable diagrams, drawing and painting with your AI assistant. Work together through a supported host, deliver an editable offline file, or embed the editor or reader in your app.

Start

1. Work live with a person. Connect an MCP client to https://mcp.rapier.website/door/mcp over streamable HTTP, then call open. Open the returned editor_url for the person. Read rapier://guide for editing, drawing, painting, comments, review and export. No account or key is required.
2. Hand over an offline document. npx rapier-html notes.md writes notes.rapier.html: the editor and its document in one file. Package.
3. Put Rapier in your app. npm install rapier-embed embeds the editor or the lightweight reader. Enable agent: true on the editor for your app's own agent over WebMCP. Your app owns storage; the reader is read-only. Embedding.
4. Keep rich documents in Markdown. npm install rapier-markdown-kit reads and writes pictures, editable drawings and layout in one .md file. Respect Will/1 regions: edit, append and keep. Self-contained Markdown.
5. Encode JPEG XL in JavaScript. npm install rapier-jxl adds the encoder that Rapier uses, in browsers, Node.js and other JavaScript runtimes. Encoder.
6. Run your own door. rapier-server serves Markdown from your folder or S3-compatible bucket through the same MCP tools. Supply Node.js and Chromium; start with rapier-server serve <folder> and the documented browser settings.

The agent edits live, beside the person or while they are away. Rapier shows its presence and changes; the person taps a change to see what was there before and undoes anything, keeping later edits. Use show {target:"comparison"} to deliberately show a diff. Read exact source before editing, and preserve the person's typing and Will. The agent guide lists the tools and their inputs.

Agent plugins

• The repository root is an Agent Plugins package: plugin.json, mcp.json and skills/ supply four skills and the MCP door. Install this root with a client that supports Agent Plugins 1.0. Antigravity reads the same root and mcp_config.json: agy plugin install https://github.com/jackskip22/rapier-plugins
• The four skills alone, for any agent the skills command supports: npx skills add jackskip22/rapier-plugins
• cursor/: the Cursor plugin adds a rule for writing, diagrams, comparisons and paintings in an editable document. The Cursor marketplace at .cursor-plugin/marketplace.json points to it. Local installation. Install one Rapier package in each client.
• claude/: the Claude plugin: four skills and the MCP door. claude plugin marketplace add jackskip22/rapier-plugins && claude plugin install rapier@rapier
• openai/: the OpenAI package: its separately retained skills and remote MCP endpoint.
• The door, https://mcp.rapier.website/door/mcp, is in the MCP registry as io.github.jackskip22/rapier (server.json). Any MCP client connects to it with no account or key.

npm packages

• npm/rapier-html/: npx rapier-html@1.2.9 notes.md writes one offline HTML file: the editor with the document inside.
• npm/rapier-embed/: npm install rapier-embed@1.2.9 puts the read-only reader or the document editor in your site or app, saving to your own storage (MIT).
• npm/rapier-markdown-kit/: read, write and render Self-contained Markdown, one .md file with its pictures and layout, without the editor (MIT).
• The JPEG XL encoder inside Rapier is rapier-jxl, published from jackskip22/rapier-jxl.

Plug-in files

Rapier pages download these the first time a document needs them, through https://cdn.jsdelivr.net/gh/jackskip22/rapier-plugins@v1.2.9/<directory>/<file> (each release's own tag), and verify each by length and SHA-384. To keep the reader's plug-ins in your own app, run npx rapier-embed@1.2.9 plugins <directory>; see Plug-ins.

• math/: The pinned app Math renderer, its complete notices and original input identities.
• letters/: Draw's letter sets, ornamental capitals traced from the British Library's book scans (CC0).
• flowchart/, docx/, pdf/: the reader's own plug-ins, a file each: the flowchart renderer, the Word reader and the PDF reader's page reading.
• sources/reader-1.2.9/: the source of those three plug-ins, which builds them offline (its README.reader-plugins.md).

Source: github.com/jackskip22/rapier. Privacy and terms.