MCP Coverage Lens


An MCP (Model Context Protocol) server that reads test coverage reports and provides coverage data to AI assistants like Claude.

How It Works

1. The server reads Clover XML coverage reports using stream parsing for greater efficiency
2. Retrieving only data about the specified file, without loading the entire coverage report into the context window.
3. When you ask about a specific file's coverage, it extracts and returns the relevant tag
4. The AI assistant can then interpret the coverage data (line hits, branch coverage, etc.)

Features

- Reads Clover XML coverage reports (commonly generated by Istanbul/nyc, PHPUnit, and other testing tools)
- Provides file-specific coverage data on demand
- Integrates seamlessly with MCP-compatible AI clients
- Lightweight and fast with streaming XML parsing

Installation

$3

The easiest way to add Coverage Lens to Claude Code:

``bash
claude mcp add coverage-lens -- npx -y coverage-lens
`

$3

Add the following to your MCP configuration file:

`json
{
"mcpServers": {
"coverage-lens": {
"command": "npx",
"args": ["-y", "coverage-lens"]
}
}
}
`

$3

| Variable | Description | Default |
| --------------------------- | -------------------------------------------- | ----------------------- |
| COVERAGE_REPORT_FILE_PATH | Optional custom path to your clover.xml file | ./coverage/clover.xml |

Available Tools

$3

Returns coverage data for a specific file from the test report.

Parameters:

- targetFile (string, required): File name or partial path to search for

Example usage in Claude:

`
What is the test coverage for the file "UserService.ts"?

or without extension file

What is the test coverage for the file "UserController"?
`

Generating Coverage Reports

Coverage Lens reads Clover XML format. Here's how to generate compatible reports:

$3

`json
// package.json
{
"scripts": {
"test:coverage": "jest --coverage"
}
}
`

Jest generates clover.xml by default in the coverage/ directory.

Development

`bash


Clone the repository

git clone https://github.com/denisonamaral/mcp-coverage-lens.git
cd mcp-coverage-lens

Install dependencies

npm install

Build the project

npm run build

The compiled output will be in the build/ directory

`

$3

`
mcp-coverage-lens/
├── src/
│ └── index.ts # Main MCP server implementation
├── build/ # Compiled JavaScript output
├── package.json
├── tsconfig.json
└── README.md
``

$3

- TypeScript (ES2022)
- MCP SDK for server implementation
- Zod for input validation

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

License

MIT License - see LICENSE for details.