Disclaimer

This project provides several methods for connecting to the Capacities note taking app API using the Model Context Protocol (MCP). It was 100% vibe-coded with the help of Gemini 2.5 Pro. While it works, it relies on third-party adapter services and, in some cases, your own hosting. Use at your own risk.

For everyone looking for a native Bun implementation, there exists another project https://github.com/jem-computer/capacities-mcp

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Table of Contents

1. Setup for Claude Desktop (with Node.js Bridge)
   • Use this if you need to connect Claude Desktop and it requires simple tool names.
2. Setup for Simple SSE Clients (CLion, VS Code)
   • Use this for a direct connection from a compatible IDE plugin.
3. Advanced Setup for Genspark (Self-Hosted Server)
   • The most reliable and robust method. Use this for Genspark or any other client if you have your own server/VPS.

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General Prerequisites

• A Capacities API Token. You can generate this from your Capacities account settings if you have a paid account.
• The MCP Link Generator tool: https://mcp-link.vercel.app/

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Setup 1: Claude Desktop (with Node.js Bridge)

This method uses the included capacities-claude-bridge.js script to act as a translator between Claude Desktop (which needs simple tool names) and the MCP adapter (which creates complex names).

Step 1.1: Install Node.js and Download Files

1. Install Node.js: Go to the official Node.js website and download and install the LTS version for your operating system.

2. Download the Bridge Code: Open a terminal (like Git Bash, Command Prompt, or PowerShell) and run the following commands:

   # Clone the repository to a permanent location
   git clone https://github.com/natkitten/capacities-mcp-bridge-unofficial.git
   
   # Navigate into the project folder
   cd capacities-mcp-bridge-unofficial
   

3. Install Dependencies: While inside the capacities-mcp-bridge-unofficial folder, run:

   npm install
   

Step 1.2: Generate the Server URL for the Bridge

1. Go to mcp-link.vercel.app.
2. Fill in the form:
   • OpenAPI Specification URL: Use this specific URL for the Claude bridge setup. It uses snake_case operationIds.

     https://gist.githubusercontent.com/natkitten/e6ce1335c2cdad87a9237156c5cda315/raw/capacities_openapi_2.json
     

   • API Base URL: https://api.capacities.io
   • HTTP Headers: Enter your Authorization header:

     Authorization: Bearer YOUR_CAPACITIES_API_TOKEN
     

   • Path Filters: Leave this field completely empty.
   • Encoding Options: Select "Base64 (JSON Encoded)".
3. Click "Generate MCP Link" and copy the resulting URL.

Step 1.3: Configure the Bridge Script

1. Open the capacities-claude-bridge.js file (located in the folder you just downloaded) in a text editor.
2. Paste the URL you just copied, replacing the placeholder text for the SSE_URL constant.

   const SSE_URL = 'https://mcp-openapi-to-mcp-adapter.onrender.com/sse?code=...'; // YOUR URL HERE
   

3. Save the file.

Step 1.4: Configure Claude Desktop (Windows)

1. Open File Explorer and navigate to your Claude Desktop config file by pasting this path into the address bar: %APPDATA%\Claude Desktop\claude_desktop_config.json
2. Open the file and add the mcp_bridges section as shown below.

   {
     "mcpServers": {
       "capacities": {
         "command": "node",
         "args": ["C:\\path\\to\\your\\capacities-mcp-bridge-unofficial\\capacities-claude-bridge.js"]
       }
     }
   }
   

   CRUCIAL: Replace C:\\path\\to\\your\\capacities-mcp-bridge-unofficial with the actual, absolute path to the folder where you cloned the repository. Remember to use double backslashes \\.
3. Save the claude_desktop_config.json file and restart Claude Desktop.

Capacities API at a glance

Endpoint	What it does	Typical use-case
GET /spaces	Lists all Capacities spaces the token can access	Show a picker or verify the token
GET /space-info	Returns structures, collections & property definitions of a space	Needed once at startup to map IDs to human labels
GET /search	Full-text or title search across one or many spaces	Let the LLM find existing notes before it creates new ones
POST /save-weblink	Saves an external URL (and optional tags/markdown) into a space	Quick bookmarking from chat
POST /save-to-daily-note	Appends Markdown to today’s daily note in a space	Fast journaling / meeting-note dump

Current rate-limits (per user / 60 s window):

• /spaces & /space-info: 5 requests
• /search: 120 requests
• /save-weblink: 10 requests
• /save-to-daily-note: 5 requests

For everything else (errors, structures, OpenAPI spec), see the official docs ➜ https://api.capacities.io/docs/.

https://github.com/user-attachments/assets/257aada5-5f65-4aec-b7da-4766452e3cb5

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Setup 2: Simple SSE for IDEs (Cline/RooCode in VS Code)

This method is for MCP plugins that can handle the mcplink_... tool names directly. No bridge script is needed.

1. Follow Step 1.2 above to generate your unique Server URL from mcp-link.vercel.app, using the capacities_openapi_2.json and leaving "Path Filters" empty.
2. Find the MCP configuration file for your IDE. It's often located at YOUR_HOME_DIRECTORY/.mcp/servers.json.
3. Add the following entry, replacing the placeholder with your generated URL:

   {
     "servers": {
       "capacities": {
         "url": "PASTE_YOUR_GENERATED_URL_HERE"
       }
     }
   }
   

4. Restart your IDE. The tools should appear with their full mcplink_... names.

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Setup 3: Advanced Self-Hosted Server for Genspark

This is the most reliable method. It runs the MCP server on your own VPS. This setup requires a slightly different OpenAPI spec to work around a parser bug in the self-hosted server package.

Step 3.1: VPS and Node.js Setup

1. Connect to your VPS via SSH (ssh root@YOUR_VPS_IP).
2. Install nvm (Node Version Manager):

   curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.39.7/install.sh | bash
   

3. Activate nvm:

   export NVM_DIR="$HOME/.nvm"
   [ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh"
   

4. Add nvm to your shell profile so it loads automatically on every login:

   echo 'export NVM_DIR="$HOME/.nvm"' >> ~/.bashrc
   echo '[ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh"' >> ~/.bashrc
   

5. Install Node.js (LTS version):

   nvm install --lts
   

Step 3.2: Create and Configure the Server

1. Create a project directory on your VPS and navigate into it:

   mkdir capacities-mcp-server
   cd capacities-mcp-server
   

2. Initialize a Node.js project: This creates the package.json file.

   npm init -y
   

3. Set the project type to "module": Open the package.json with nano package.json and add "type": "module", after the "main": "index.js", line.
4. Install pm2 and the server package locally: We install them here to keep the project self-contained.

   npm install pm2 @ivotoby/openapi-mcp-server
   

Step 3.3: Create the Server Configuration

1. Create an ecosystem.config.cjs file for pm2. The .cjs extension is important.

   nano ecosystem.config.cjs
   

2. Paste the following configuration into the file. This uses the locally installed pm2 and server script.

   module.exports = {
     apps : [{
       name   : 'capacities-mcp',
       script : './node_modules/@ivotoby/openapi-mcp-server/dist/cli.js',
       args   : [
         '--openapi-spec',
         'https://gist.githubusercontent.com/natkitten/37e88b5dab4195b0f4d650f31f5505bf/raw/capacities_openapi_3.json',
         '--api-base-url',
         'https://api.capacities.io',
         '--headers',
         'Authorization:Bearer YOUR_CAPACITIES_API_TOKEN',
         '--toolNameFormat',
         '**',
         '--transport',
         'http',
         '--host',
         '0.0.0.0',
         '--port',
         '8448' // Or your preferred port
       ]
     }]
   }
   

   Replace YOUR_CAPACITIES_API_TOKEN with your actual token.

3. Save and exit (CTRL + X, Y, Enter).

Step 3.4: Run the Server

1. Start the server using the local pm2:

   ./node_modules/pm2/bin/pm2 start ecosystem.config.cjs
   

2. Check logs to confirm it's listening on your port: pm2 logs capacities-mcp
3. Save the configuration for reboots: pm2 save
4. Enable pm2 on startup: Run pm2 startup and follow the on-screen instructions.

Step 3.5: Configure Firewall, Caddy, and Genspark

1. Firewall: Open your chosen port (8448 in this example) on both your VPS firewall (sudo ufw allow 8448) and your cloud provider's firewall (in the Hostinger dashboard).
2. Caddy: For a secure HTTPS URL, set up a reverse proxy in your Caddyfile.

   mcp.yourdomain.com {
       reverse_proxy localhost:8448
   }
   

   Reload Caddy to apply the changes (sudo systemctl reload caddy).
3. Genspark:
   • Server Type: StreamableHttp
   • Server URL: https://mcp.yourdomain.com/mcp (using the /mcp path).
   • Request Header:

     {"Content-Type": "application/json"}
     

4. Add the server and test it.

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Licensed under the MIT License — see LICENSE for details