What is Deno Mcp

The Deno Model Context Protocol (MCP) server is a tool that facilitates interaction between AI assistants, such as Cursor, and Deno projects, allowing for functionalities like running tests and viewing code coverage directly in the development environment.

Use cases

Use cases for Deno MCP include executing tests for specific files or entire projects, collecting code coverage data, and integrating AI tools to streamline the development workflow.

How to use

To use the Deno MCP server, add the required configuration to your workspace’s ‘.cursor/mcp.json’ file. After configuring, restart the MCP tool in Cursor settings to apply the changes.

Key features

Key features include running Deno tests with various options (like coverage, documentation evaluation, snapshot updates, and resource leak tracing) and viewing detailed code coverage reports generated by ‘deno coverage’.

Where to use

Deno MCP can be used in software development environments where Deno is employed, particularly in projects that require integration with AI assistants for enhanced testing and code analysis.

Deno MCP Server

The Deno Model Context Protocol (MCP) server provides a bridge for AI
assistants, like Cursor, to interact with your Deno projects. It enables
functionalities such as running tests and viewing code coverage directly within
your development environment.

Features

• Run Deno Tests: Execute tests for specific files, directories, or your
  entire project.
  • Supports standard Deno test options:
    • --coverage: Collect coverage profile data.
    • --doc: Evaluate code blocks in JSDoc and Markdown.
    • --update: Update snapshot files for test cases.
    • --trace-leaks: Enable tracing of resource leaks.
• View Code Coverage: Display detailed coverage reports generated by
  deno coverage.

Getting Started

To integrate the Deno MCP server with Cursor, add the following configuration to
your workspace’s .cursor/mcp.json file:

{
  "mcpServers": {
    "deno": {
      "command": "deno",
      "args": ["run", "-A", "jsr:@udibo/deno-mcp", "-A"]
    }
  }
}

After adding this configuration, restart the MCP tool in your Cursor settings to
apply the changes.

Important Note on Arguments: Any arguments provided in the args array
after the script path (e.g., jsr:@udibo/deno-mcp or ./custom-server.ts)
will be automatically passed to the deno test command when the test tool is
executed. For instance, the trailing -A in the example configurations above
will be included in all test tool invocations, effectively running tests with
all permissions by default.

Example Usage

Here’s an example of Cursor interacting with the Deno MCP server to run tests:

Extending the Server

You can extend the base Deno MCP server with your own custom tools. This allows
you to tailor its functionality to your specific project needs.

Example: Adding an echo tool

1. Create a new TypeScript file (e.g., custom-server.ts):

   import { server, StdioServerTransport } from "jsr:@udibo/deno-mcp"; // Or your local path if developing
   import { z } from "https://deno.land/x/[email protected]/mod.ts"; // Or your preferred way to import Zod
   
   server.tool(
     "echo",
     {
       message: z.string().describe("The message to echo."),
     },
     {
       "title": "Echo Message",
       "description": "A simple tool that echoes back the provided message.",
     },
     ({ message }) => {
       return Promise.resolve({
         content: [{
           type: "text",
           text: `Echo: ${message}`,
         }],
       });
     },
   );
   
   if (import.meta.main) {
     const transport = new StdioServerTransport();
     await server.connect(transport);
   }
   

2. Update your .cursor/mcp.json to use your custom server script:

   {
     "mcpServers": {
       "deno": {
         "command": "deno",
         "args": ["run", "-A", "./custom-server.ts", "-A"]
       }
     }
   }
   

3. Important: Restart the MCP tool in your Cursor settings for the changes
   to take effect. Remember the note above about arguments: the trailing -A
   here will also be passed to deno test.

Contributing

Contributions are welcome! Please feel free to open an issue or submit a pull
request.

License

This project is licensed under the MIT License. See the LICENSE
file for details.