Connecting Your Joplin Notes to Claude: Building an MCP Server in Go

I built a Windows system tray application to connect Joplin’s knowledge base with Claude using the Model Context Protocol (MCP). Here is how it works and how to set it up.

The Goal

Joplin is excellent for private note-taking, and Claude is a capable AI assistant. Integrating them allows Claude to read, create, and update notes directly.

The Model Context Protocol (MCP)

Anthropic’s MCP is a standardized protocol allowing AI assistants to connect with external tools. It enables Claude to use defined “tools” naturally within a conversation without complex prompting.

The Solution

A Go-based Windows application that:

1. Runs in the system tray
2. Connects to Joplin’s REST API (via Web Clipper)
3. Exposes 8 tools to Claude via MCP

Available Tools

Reading & Discovery:

• list_notes: Browse notes or filter by notebook
• get_note: Retrieve note content by ID
• search_notes: Search using Joplin’s syntax
• list_folders: View notebooks
• list_tags: View tags

Creation & Management:

• create_note: Create new notes
• update_note: Modify existing notes
• delete_note: Remove notes

Use Cases

• Contextual Search: “What notes do I have about the Q4 project?”
• Automated Summaries: “Create a new note summarizing our discussion.”
• Updates: “Add these action items to my meeting notes.”

Technical Architecture

• Language: Go (chosen for speed and single-binary compilation)
• Protocol: MCP over HTTP JSON-RPC
• Joplin Integration: REST API
• UI: Windows system tray (getlantern/systray)

Components

1. Joplin Client: Handles HTTP communication with Joplin using the API token.
2. MCP Server: Routes JSON-RPC requests from Claude to Joplin tools.
3. System Tray: Provides a lightweight interface to manage the background process.

Installation

Prerequisites

• Joplin Desktop (Web Clipper enabled)
• Windows 10+

Steps

1. Get API Token: In Joplin, go to Tools → Options → Web Clipper. Enable it and copy the token.
2. Configure: Create a config.json file:

   {
     "joplin_port": 41184,
     "joplin_token": "your_token_here",
     "mcp_port": 3000
   }

3. Run: Execute ./joplin-mcp-server.exe.
4. Connect Claude: Add to your claude_desktop_config.json:

   {
     "mcpServers": {
       "joplin": {
         "url": "http://localhost:3000",
         "transport": "http"
       }
     }
   }

5. Restart Claude.

Why Go?

• Speed: Instant startup (~100ms) and minimal memory usage (~15MB).
• Simplicity: Compiles to a single static binary with no runtime dependencies.
• Concurrency: Efficient handling of multiple requests.

Open Source

The project is MIT licensed and available on GitHub.

• GitHub Repository: rpfilomeno/joplin-mcp-go
• Joplin REST API Docs: joplinapp.org/api
• MCP Specification: spec.modelcontextprotocol.io