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When you install a Connection from Highlight’s registry, we take care of Connection setup for you. However, if you are developing a custom connection, your custom MCP server is not in our registry or a connection not coded in JavaScript, you can use ‘Custom Command’ to setup your connection in Highlight.

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Prerequisites

  • A basic understanding of your development environment and the command line.
  • Environment variables and arguments to pass to the connection.

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Setup

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Step 1: Preflight Checks

Before we get started, Highlight can check if your environment is ready for connection development. Go to connections page in Highlight app, and click ‘Installed connections’ tab. You will see a list of connections installed on your machine and a button to ‘Check Compatibility’.
Connections Page
Click ‘Check Compatibility’ and Highlight will check if your environment is ready for connection development.
Connection Compatibility Check
If you see a green checkmark, your environment is ready for connection development. If you see a red X, your environment is not ready for connection development. Here are some missing dependencies you need to install:
  • Node.js
  • Python
  • npm
  • uv

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Node.js

Node.js is a JavaScript runtime that allows you to run JavaScript code outside of the browser. You can download it from Node.js website.

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Python

Python is a programming language that allows you to work quickly and integrate systems more effectively. You can download it from Python website.

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npm

npm is a package manager for JavaScript and the world’s largest software registry. You can download it from npm website.

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uv

uv is a faster package manager for JavaScript and the world’s largest software registry. You can download it from uv website. If you don’t see a green checkmark, but you have all the prerequisites installed, you can click ‘Retry’ to check again. If you are still having issues, contact us on Discord.

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Step 2: Add a custom connection

Now with your environment ready, you can add a custom connection to Highlight. Go to connections page in Highlight app, and click ‘Custom connection’ button.
connections Page
After clicking ‘Custom connection’ button, you will be asked to choose a connection type.
connection Types
You can choose between ‘SSE’ or ‘stdio’ connection types. SSE means Server-Sent Events and stdio means Standard Input Output. For more information on the difference between the two, please refer to the Understanding Connections page. After choosing a connection type, based on your connection type, you will be asked to provide a command to run your connection.

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SSE connection Setup

For SSE connections, you will be asked to provide a URL to run your connection. This URL will be run when you connect your connection to Highlight.
SSE connection Setup
After providing the URL and the connection name you can start using your connection in Highlight.

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stdio connection Setup

For stdio connections, you will be asked to provide a command to run your connection.
stdio connection Setup
Provide a connection Name and let’s follow an MCP server example to setup your connection. In this example, we will use example filesystem server from MCP Server Examples as our MCP server. Scroll down on the page till you find the NPX setup section. Here is the command in JSON format like Claude Desktop uses; 
{
  "mcpServers": {
    "filesystem": {
      "command": "npx",
      "args": [
        "-y",
        "@modelcontextprotocol/server-filesystem",
        "/Users/username/Desktop",
        "/path/to/other/allowed/dir"
      ]
    }
  }
}
So let’s start by filling in the command and args in our connection setup modal, like this;
Filled Setup Example
After filling in the command and args, you can start using your connection in Highlight.
stdio connection Setup Successful
You can now start using your connection in Highlight by mentioning it in your messages.
Filesystem MCP Server Call Floaty
Congratulations! You have successfully setup a custom connection in Highlight. Now let’s answer some frequently asked questions.

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Frequently Asked Questions

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How do I update my connection?

If you are using custom connection setup, you can update your connection by turning off the connection and then turning it on again. This will trigger a new connection setup process and you will be able to update the connection command and args.

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How do I delete my connection?

If you are using custom connection setup, you can delete your connection from the Installed connections page. Click on the connection you want to delete you will see a ‘Delete connection’ button on the bottom right corner of the connection card.
Delete connection Button
Click on the ‘Delete connection’ button and you will be asked to confirm the deletion.

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MCP Error -32000: Connection Closed Error

If you see an error like this from your custom connection;
MCP Error -32000: Connection Closed
It means your connection didn’t start correctly. Please check your connection command, args and Environment Variables to make sure they are correct. If you are still having issues please contact us on Discord. We will be happy to help you.

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Understanding the connection Path Field

The connection Path field specifies the location of your connection’s executable or entry point file. This field works in conjunction with the command to properly launch your connection. For example:
  • For a JavaScript connection: Use node as the command and /path/to/my_connection.js as the connection Path
  • For a Python script: Use python3 as the command and /path/to/connection.py as the connection Path
While this field appears in the setup form, it’s actually optional in many cases. If your connection is accessible through a package manager or if you’ve specified the full path in your command or arguments, you can leave this field empty. It’s provided as a convenience to simplify connection configuration, especially for local development.
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